WO2021008457A1

WO2021008457A1 - High-voltage flip-chip led light source, large-area led light source packaging structure and packaging method

Info

Publication number: WO2021008457A1
Application number: PCT/CN2020/101342
Authority: WO
Inventors: 唐文婷; 蔡勇
Original assignee: 中国科学院苏州纳米技术与纳米仿生研究所
Priority date: 2019-07-15
Filing date: 2020-07-10
Publication date: 2021-01-21

Abstract

A high-voltage flip-chip LED light source, a large-area LED light source packaging structure and packaging method, wherein the large-area LED light source packaging structure comprises a first substrate (10), a first LED chip (20) and a heat conductive connecting structure (30) arranged between the first LED chip (20) and the first substrate (10), the heat conductive connecting structure (30) comprises a plurality of insulating heat conductors (31) arranged at intervals. The high-voltage flip-chip LED light source comprises a second substrate (1) and a second LED chip (2), wherein a third surface (201) of the second LED chip (2) is provided with an electrode, a fourth surface (202) is a light emitting surface, at least one boss (11) is formed on the surface of the second substrate (1), and the third surface (201) of the at least one second LED chip (2) is connected with the top end surface of the boss (11) through an insulating heat conductive connecting adhesive (3). The large-area LED light source packaging structure solves the problem of uneven heat dissipation caused by warping of the first LED chip (20) in a large area; the second LED chip (2) in the high-voltage flip-chip LED light source can be seamlessly combined with the second substrate (1), and can avoid the problem that the insulating heat conductive connecting adhesive (3) overflows to the conductive electrode.

Description

High-voltage flip-chip LED light source, large-area LED light source packaging structure and packaging method

This application is based on and requires that the application number submitted on July 15, 2019 is 2019106347032, the Chinese patent named high-voltage flip-chip LED light source, and the application number submitted on September 9, 2019 is 201910866077X, the name is large area LED Priority of the Chinese patent for light source packaging structure and packaging method.

Technical field

The application relates to an LED light source packaging structure, in particular to a high-voltage flip-chip LED light source, a large-area LED light source packaging structure and packaging method, and belongs to the field of semiconductor technology.

Background technique

As the fourth-generation electric light source, high-power LED is called "green lighting source". It has the advantages of small size, safe low voltage, long life, high electro-optical conversion efficiency, fast response speed, energy saving, and environmental protection, and has a wide application prospect. However, if the traditional LED packaging technology is used to encapsulate high-power LED light sources, a series of problems such as heat conduction and insulation will often occur, which will affect the performance of the final product. But for these problems, the industry has not been able to explore effective solutions.

Application content

The main purpose of this application is to provide a high-voltage flip-chip LED light source, a large-area LED light source packaging structure and a packaging method to overcome the deficiencies in the prior art.

In order to achieve the purpose of the aforementioned application, the technical solutions adopted in this application include:

The embodiment of the present application provides a large-area LED light source packaging structure, which includes a first substrate, a first LED chip, and a thermally conductive connection structure disposed between the first LED chip and the first substrate. The thermally conductive connection structure includes each other A plurality of insulating thermal conductors are arranged at intervals. One end of the insulating thermal conductor is bonded to the first LED chip through an insulating and thermally conductive connecting glue, and the other end is thermally connected to the first substrate through a thermally conductive solder, so that the first substrate and the first A plurality of insulating and heat conducting channels are formed between the LED chips.

The embodiment of the present application also provides a method for packaging a large area LED light source, which includes:

Bonding one end of a plurality of insulating thermal conductors spaced apart from each other to the first LED chip via an insulating and thermally conductive connecting glue, so that the distribution form of the plurality of insulating thermal conductors matches the overall structure of the first LED chip; and

The other ends of the plurality of insulating thermal conductors are thermally connected to the first substrate via a thermally conductive solder, thereby forming a plurality of insulating and thermally conductive channels between the first substrate and the first LED chip.

An embodiment of the present application provides a high-voltage flip-chip LED light source, including a second substrate and a second LED chip, wherein the second substrate is a thermally conductive substrate, and the second LED chip is a high-voltage flip-chip LED chip;

The third surface of the second LED chip has electrodes, the fourth surface is a light-emitting surface, the third surface is opposite to the fourth surface, and at least one boss is formed on the surface of the second substrate, at least one of which is The third surface of the second LED chip is connected to the top surface of a boss through an insulating and thermally conductive connecting glue.

In the large-area LED light source packaging structure provided by the embodiments of the present application, a plurality of insulating heat conductors are arranged between the first substrate and the first LED chip of high voltage, high power and large size. The warping structure of an LED chip is matched, and one end of the insulating heat conductor is pasted on the first substrate with a heat conductive solder, thereby forming a good insulating and heat conducting channel, which solves the problem of warping of the first LED chip with a large area. The problem of uneven heat dissipation; and, because the contact area between the single insulating heat conductor and the first LED chip is small, the thermal expansion stress can be reduced and the reliability of the device can be improved;

In the high-voltage flip-chip LED light source provided by the embodiments of the present application, the second chip can be seamlessly combined with the second substrate, and the problem of overflow of the connecting glue to the conductive electrode can be avoided, thereby ensuring the effectiveness of electrical connection. It can also enhance the heat dissipation uniformity of the LED flip chip. At the same time, the second LED chip used is a monolithic integrated high-power high-voltage flip-chip LED chip, which has the characteristics of good stability and high failure resistance. The special position design of the electrode area and the light-emitting area can effectively increase the chip area The utilization rate maximizes the area of the light-emitting area, and also ensures that the thermally conductive insulating layer material does not overflow to the electrode surface during packaging, and that the solder does not overflow into the light-emitting area to cause a short circuit.

Description of the drawings

Figure 1a is a schematic structural diagram of an existing flip-chip LED light source;

Figure 1b is a schematic diagram of an existing flip-chip LED light source;

2 is a schematic diagram of the principle structure of a large-area LED light source packaging structure in a typical implementation case of the present application;

3 is a schematic structural diagram of a large-area LED light source packaging structure in Embodiment 1 of the present application;

4 is a schematic structural diagram of a large-area LED light source packaging structure in Embodiment 2 of the present application;

5 is a schematic structural diagram of a large-area LED light source packaging structure in Embodiment 3 of the present application;

6 is a schematic structural diagram of a large-area LED light source packaging structure in Embodiment 4 of the present application;

FIG. 7 is a schematic structural diagram of the connecting portion between the chip and the metal heat conductor in a large-area LED light source packaging structure in

Embodiment

3 or 4 of the present application;

8 is a schematic diagram of a high-voltage flip-chip LED light source in Embodiment 5 of the present application;

9 is a schematic structural diagram of a second LED chip in Embodiment 5 of the present application;

10 is a schematic diagram of a high-voltage flip-chip LED light source in Embodiment 6 of the present application;

11 is a schematic diagram of a high-voltage flip-chip LED light source in Embodiment 7 of the present application;

12 is a schematic diagram of a high-voltage flip-chip LED light source in Embodiment 8 of the present application;

13 is a schematic diagram of a high-voltage flip-chip LED light source in Embodiment 9 of the present application;

FIG. 14 is a schematic structural diagram of a second LED chip in an embodiment of the present application;

15 is a schematic structural diagram of a second LED chip in another embodiment of the present application;

FIG. 16 is a schematic structural diagram of a second LED chip in another embodiment of the present application.

Detailed ways

In view of the shortcomings in the existing technology, the applicant in this case was able to propose the technical solution of the application after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

Obviously, the drawings in the following description are only some of the embodiments described in this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Furthermore, it should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these There is any such actual relationship or sequence between entities or operations. Moreover, the terms "include", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also includes Other elements of, or also include elements inherent to this process, method, article or equipment. If there are no more restrictions, the element defined by the sentence "including at least one..." does not exclude the existence of other same elements in the process, method, article, or equipment including the element.

For high-power LED chips, as the area of the LED chip increases, the warpage of the chip will increase, so that during packaging, the distance between the chip and the substrate is different, which causes the thermal resistance of each place to be different, which leads to poor heat dissipation. Both affect device performance.

In view of the problems existing in the prior art, one aspect of the embodiments of the present application provides a large-area LED light source packaging structure, which includes a first substrate, a first LED chip, and a package disposed between the first LED chip and the first substrate. A thermally conductive connection structure, the thermally conductive connection structure includes a plurality of insulating thermal conductors spaced apart from each other, one end of the insulating thermal conductor is bonded to the first LED chip through an insulating and thermally conductive connecting glue, and the other end is thermally connected to the first substrate through a thermally conductive solder , Thereby forming a plurality of insulating and thermally conductive channels between the first substrate and the first LED chip.

Further, the heat conduction connection structure further includes a plurality of metal heat conductors electrically isolated from each other arranged at one end of the at least one insulating heat conductor, and one end of the insulating heat conductor is electrically isolated from each other by the plurality of metal heat conductors and the first heat conductor. The LED chip is thermally connected.

Further, the metal heat conductor has an island shape.

Further, the shape of the insulating heat conductor includes a rectangular parallelepiped shape or a cylindrical shape.

In some more specific implementations, the first LED chip is a flip chip, the first surface of the flip chip having electrodes is thermally connected to the first substrate through a thermally conductive connection structure, and the second flip chip The surface is a light-emitting surface, and the first surface and the second surface are arranged opposite to each other.

Further, an insulating layer is provided on the surface of the first substrate, a conductive layer is provided on the insulating layer, and the electrode of the first LED chip is electrically connected to the conductive layer via a hard conductive material or a conductive lead.

In some more specific implementations, the first LED chip is a flip chip, and one end of the insulating heat conductor is thermally connected to the first LED chip through a plurality of metal heat conductors that are electrically isolated from each other. The distance between the thermal conductors is c≥1μm, and at least a pair of P and N electrodes of the first LED chip are thermally connected to the front surface of the first substrate through the plurality of spaced metal thermal conductors, and any metal thermal conductor is in parallel The maximum dimension a in the direction of the side surface of the first LED chip with the electrode is smaller than the minimum distance d between the P electrode and the N electrode, and d>a≧2 μm.

In some more specific implementations, the first LED chip is a front-mounted chip, the second surface of the front-mounted chip is thermally connected to the first substrate through a thermally conductive connection structure, and the first surface of the front-mounted chip is a light-emitting surface and There is an electrode, and the first surface and the second surface are arranged opposite to each other.

Further, the first LED chip has a warped structure as a whole, and the distribution form of the plurality of insulating thermal conductors matches the warped structure.

Further, the first substrate is a metal first substrate or a non-metal first substrate, the material of the metal first substrate includes aluminum or copper, and the material of the non-metal first substrate includes ceramic, but is not limited to this.

Compared with the formal chip, the flip chip has the advantages of lower thermal resistance, better light extraction, no gold wire, better integration and simpler production. At present, due to technical limitations, in order to ensure the yield of the chip, the industrial level of flip-chip LED chips generally have the characteristics of small power, small area and low integration. This feature largely limits the flip-chip LED The application of this makes the flip-chip LED market appear blank. To fill this gap and expand the application range of flip-chip LEDs, it is urgent to obtain high-power and high-voltage integrated flip-chip LED chips that can be used for industrialization. However, at present, high-power and high-voltage integrated flip-chips are faced with a number of technical problems during packaging, such as the problem of overflow of insulating bonding glue that affects the conductivity of the electrodes; and the problem of heat conduction and insulation between the light-emitting area of the chip and the substrate. In view of the problems existing in the prior art, another aspect of the embodiments of the present application provides a high-voltage flip-chip LED light source, which includes a second substrate and a second LED chip, wherein the second substrate is a thermally conductive substrate, and the The second LED chip is a high-voltage flip-chip LED chip;

Further, the top surface of the boss is also covered with a thermally conductive insulating layer, and the third surface of the second LED chip is connected to the thermally conductive insulating layer through an insulating and thermally conductive connecting glue.

Wherein, the thermally conductive insulating layer is formed of a thermally conductive insulating material. In addition, the thermally conductive insulating layer is transferred from the outside, or the thermally conductive insulating layer is at least integrally formed on the top surface of the boss.

Further, the material of the second substrate includes an electrically and thermally conductive metal material, and the electrically and thermally conductive metal material includes copper or aluminum, and is not limited thereto.

Further, the thermally conductive insulating layer is a dense thermally conductive insulating passivation layer formed by chemically treating the surface of the second substrate.

Further, the entire second substrate or the boss is formed of a thermally conductive insulating material.

Further, the thermally conductive insulating material includes any one of oxide, nitride, and carbide, and is not limited thereto.

For example, the oxide includes aluminum oxide or copper oxide, etc., the nitride includes aluminum nitride, silicon nitride, or beryllium nitride, and the carbide includes silicon carbide, but not limited thereto.

Further, the second LED chip is a monolithic integrated high-power high-voltage flip-chip LED chip, the second LED chip includes an electrode area and a light-emitting area, the electrode area is spaced apart from the light-emitting area, and the light-emitting area includes multiple A unit cell capable of independently emitting light, the multiple unit cells are arranged in series and/or in parallel, and the multiple unit cells are electrically connected to the electrode area.

Further, a gas storage space is also distributed in the second LED chip, and the gas storage space includes a groove-shaped structure formed between the unit cells.

Further, the second LED chip has more than one set of electrode regions, and each set of electrode regions includes two symmetrically arranged electrode regions, and the electrode regions have a triangular structure or a linear structure.

Preferably, the second LED chip has a set of electrode areas, and the set of electrode areas is two symmetrically arranged triangular electrode areas.

Further, the electrode area of the second LED chip is combined with a hard conductive material (such as a metal sheet, a metal wire, etc., but not limited thereto), and the hard conductive material is connected to the substrate through silver paste or electrical welding material. The conductive lines on the electrical connection.

Further, the distance between the light-emitting area and the electrode area satisfies the following condition: in the process of connecting the third surface of the second LED chip to the top surface of the boss through an insulating and thermally conductive connecting glue, there is no insulation The thermally conductive connecting glue overflows to the surface of the electrode area.

Example 1

2 and 3, a large-area LED light source packaging structure includes a first substrate 10, a first LED chip 20, and a thermally conductive connection structure 30 disposed between the first substrate 10 and the first LED chip 20, The connecting structure 30 includes a plurality of insulating thermal conductors 31 spaced apart from each other. One end of the insulating thermal conductor 31 is bonded to the first LED chip 20 through an insulating and thermally conductive connecting glue 40, and the other end is thermally connected to the first substrate 10 through a thermally conductive solder 50, thereby A plurality of insulating and heat-conducting channels are formed between the first substrate 10 and the first LED chip 20; the first LED chip has a warped structure as a whole, and the distribution form of the plurality of insulating heat conductors 31 matches the warped structure, that is, a plurality of One end of the insulating thermal conductor 31 forms an arc surface matching the surface of the first LED chip; and an electrode lead-out structure is also provided on the first substrate 10, and the electrode of the first LED chip is electrically connected to the electrode lead-out structure.

Specifically, the first LED chip 20 is a flip chip. The first LED chip 20 has a first side and a second side opposite to each other. An electrode is provided on the first side of the first LED chip 20. The first LED The chip 20 is connected and combined with the insulating thermal conductor 31 by a first surface with electrodes. The electrode lead structure includes solder 63 and a pad 65. The solder 63 and the pad 65 are electrically connected via a conductive layer 51, and the solder 63 is passed through a hard conductive material. (For example, a conductive metal sheet) 64 is electrically connected to the electrode of the first LED chip; wherein an insulating layer 62 is provided between the electrode extraction structure and the first substrate 10, and an insulating layer is also provided on the upper surface of the conductive layer 51 61.

Specifically, the structure or shape of the insulating thermal conductor 31 is a rectangular parallelepiped, a cube, a cylindrical shape, a truncated cone, or a prismatic shape, etc., and the plurality of insulating thermal conductors 31 are of length, or may be of unequal length.

Specifically, the method of combining the insulating thermal conductor 31 and the first LED chip 20 may be insulating bonding glue, self-aligning isolation technology, etc.; the method of combining the insulating thermal conductor 31 and the first substrate 10 may be reflow soldering, silver paste , Soldering and other methods.

The first substrate 10 may be a metallic first substrate or a non-metallic first substrate. The material of the metallic first substrate may be a metal with good thermal conductivity such as aluminum or copper, and the material of the non-metallic first substrate includes ceramics.

More specifically, first, one end of the insulating thermal conductor 31 is self-adaptively pasted on the surface of the first LED chip with high voltage, high power and large size, and one end of the plurality of insulating thermal conductors 31 forms a curved surface adapted to the surface of the first LED chip. After that, the other end of the insulating thermal conductor 31 is pasted on the first substrate via a thermally conductive solder to form a good insulating and thermally conductive channel, which solves the uneven heat dissipation caused by the large area of the first LED chip warping. The problem; and, because the contact area between the single insulating heat conductor and the first LED chip is small, the thermal expansion stress can be reduced and the reliability of the device can be improved.

Example 2

2 and 4, the structure of the large-area LED light source packaging structure in this embodiment is basically the same as the structure of the large-area LED light source packaging structure in Embodiment 1, except that: the first LED in this embodiment The chip 20 is a front-mounted chip, and the insulating heat conductor 31 is connected to the second surface of the first LED chip 20, and the electrodes of the first LED chip and the solder 63 are electrically connected by soft conductive connecting wires.

Example 3

Please refer to FIG. 5, a large-area LED light source packaging structure, including a first substrate 10, a first LED chip 20, and a thermally conductive connection structure 30 disposed between the first substrate 10 and the first LED chip 20, the thermally conductive connection structure 30 It includes a plurality of insulating heat conductors 31 spaced apart from each other. A plurality of metal heat conductors 32 that are electrically isolated from each other are provided at one end of the insulating heat conductor 31. One end of the metal heat conductor 32 is welded to the first LED chip 20, and the insulating heat conductor 31 The other end is thermally connected to the first substrate 10 through the thermally conductive solder 50, thereby forming a plurality of insulated and thermally conductive channels between the first substrate 10 and the first LED chip 20 (each insulated and thermally conductive channel in this embodiment is mainly composed of an insulating A heat conductor and a plurality of metal heat conductors arranged at one end of the insulating heat conductor); the first LED chip has a warped structure as a whole, and the distribution of the plurality of insulating heat conductors 31 and metal heat conductors 32 matches the warped structure And, an electrode lead-out structure is also provided on the first substrate 10, and the electrode of the first LED chip is electrically connected to the electrode lead-out structure.

Specifically, the first LED chip in this embodiment is a flip chip, the first LED chip 20 has a first side and a second side opposite to each other, and electrodes are provided on the first side of the first LED chip 20, The electrode lead-out structure includes solder 63 and a pad 65. The solder 63 and the pad 65 are electrically connected via a conductive layer 51, and the solder 63 is electrically connected to the electrode of the first LED chip via a hard conductive material (conductive metal sheet) 64; wherein, An insulating layer 62 is provided between the electrode extraction structure and the first substrate 10, and an insulating layer 61 is also provided on the upper surface of the conductive layer 51.

More specifically, please refer to FIG. 7. The first LED chip 20 includes an insulating layer 25, a P-type GaN layer 24, an active layer 23, an N-type GaN layer 22, and a substrate 21 that are sequentially stacked on the insulating layer 25. A P electrode 26 and an N electrode 27 are arranged at intervals. The part of the P electrode 26 penetrates the insulating layer 25 and is connected to the P-type GaN layer 24, and the part of the N electrode 27 continuously penetrates the insulating layer 25, the P-type GaN layer 24, and the active layer. 23 and arranged in the N-type GaN layer 22, the distance between the P electrode 26 and the N electrode 27 is d, the P electrode 26 and the N electrode 27 are thermally connected to at least one metal heat conductor 32, and at least the P electrode 26 and the N electrode The electrode 27 is also electrically connected to the electrode extraction structure.

Specifically, the metal heat conductor 32 may be a rectangular parallelepiped structure, with a width a, a height b, and a distance between two adjacent metal heat conductors 32 as c, where a≥2μm, c≥1μm, and the P electrode 26 The distance d between the N electrode 27 and the N electrode 27>the width a of the metal heat conductor 32.

It should be noted that the aforementioned "distance d between the P electrode 26 and the N electrode 27> the width a of the metal heat conductor 32", it can be understood that the distance between the P electrode and the N electrode is the same as the width of the metal heat conductor. The spacing in the reference direction may be the width direction of the metal heat conductor; when the metal heat conductor is a cylinder or a truncated cone structure, the predetermined direction may be a direction parallel to the side surface of the first LED chip with electrodes.

Due to the electrical isolation between the metal heat conductors, and the width of the metal heat conductors is smaller than the distance between the P and N electrodes, there will be no short circuit problem, which reduces the requirements for the accuracy of the equipment alignment. The alignment error is less than P, N The electrode area is half the size, which reduces the cost; among them, the contact area of a single metal heat conductor and the P electrode or the N electrode is small, the thermal stress of the contact surface is greatly reduced, and the reliability of the device is increased.

Specifically, the structure or shape of the insulating heat conductor 31 is a rectangular parallelepiped, a cube, a cylinder, a truncated cone or a prismatic shape, etc., and the plurality of insulating heat conductors 31 may be of equal length.

Specifically, the combination of the metal thermal conductor 32 and the first LED chip 20 can be soldering, insulating adhesive bonding, self-aligned isolation technology, etc.; the combination of the insulating thermal conductor 31 and the first substrate 10 can be reflow soldering, Silver paste, solder and other methods. Self-aligned isolation technology: Since the first substrate is provided with metal islands (ie, island-shaped metal heat conductors) that are electrically isolated and smaller than the chip electrode spacing, when the flip chip is welded to the first substrate, the chip electrodes and the metal island are not required Precise alignment can realize chip self-aligned welding without short circuit between electrodes. The first substrate 10 may be a metallic first substrate or a non-metallic first substrate. The material of the metallic first substrate may be a metal with good thermal conductivity such as aluminum or copper, and the material of the non-metallic first substrate includes ceramics.

More specifically, a plurality of metal heat conductors 32 can be pre-arranged at one end of each insulating heat conductor 31, and then the hot end of the metal conductor can be adaptively bonded to the surface of the first LED chip with high voltage, high power and large size. One end of the thermal conductor 32 forms a curved surface that is compatible with the surface of the first LED chip, and then the other end of the insulating thermal conductor 31 is pasted on the first substrate through a thermally conductive solder to form a good insulating and thermal conduction channel, which is a good solution The problem of uneven heat dissipation caused by the warpage of the large-area first LED chip is solved; and, since the contact area between the single insulating heat conductor and the first LED chip is small, the thermal expansion stress can be reduced and the reliability of the device can be improved.

Example 4

Referring to FIG. 6, the structure of the large-area LED light source packaging structure in this embodiment is basically the same as the structure of the large-area LED light source packaging structure in Embodiment 3. The difference is that the first LED chip 20 in this embodiment is When the chip is mounted, one end of the metal heat conductor 32 is connected to the second surface of the first LED chip 20 without electrodes, and the electrode of the first LED chip 20 and the solder 63 are electrically connected by a soft conductive connecting wire.

In addition, it should be noted that the plurality of insulated conductors 31 used in Examples 1-4 are all insulating heat conductors of equal length; in some more specific embodiments, insulating heat conductors of unequal length can also be used. Connect one end of a plurality of insulating heat conductors 31 to the first substrate, and the other end of the plurality of insulating heat conductors 31 (when a metal heat conductor is provided, it should be the end of the metal heat conductor here) where the surface is and The surface of the chip matches the curved surface, and then the chip is connected and combined with the insulating heat conductor 31 (when a metal heat conductor is provided, it should be a metal heat conductor here).

Or, in some other more specific embodiments, a first substrate with the same warped structure that matches the warped structure of the first LED chip can also be used, and the first LED chip and the first substrate are connected to each other. The insulating heat conductor or the insulating heat conductor and the metal heat conductor form a heat conduction channel, thereby solving the problem of uneven heat dissipation caused by the warping of the large-area first LED chip.

It should be noted that the material of the insulating thermal conductor in the embodiment of the present invention may be a material with good thermal conductivity, such as ceramics.

In the large-area LED light source packaging structure provided by the above embodiments of the present application, a plurality of insulating heat conductors are arranged between the first substrate and the first LED chip of high voltage, high power and large size, and the distribution of the plurality of insulating heat conductors is consistent with The warping structure of the first LED chip is matched, and one end of the insulating heat conductor is pasted on the first substrate with heat conductive solder, thereby forming a good insulating and heat conducting channel, which solves the problem of the large area of the first LED chip warping The problem of uneven heat dissipation; and, because the contact area between the single insulating heat conductor and the first LED chip is small, the thermal expansion stress can be reduced, and the reliability of the device can be improved.

Example 5

Please refer to FIG. 8, a high-voltage flip-chip LED light source, which includes a second substrate 1 (hereinafter also referred to as "substrate") and a second LED chip 2 (hereinafter also referred to as "chip" or "LED chip"). The second substrate is a thermally conductive substrate, the second LED chip is a high-voltage flip-chip LED chip; the third surface 201 of the second LED chip has electrodes, the fourth surface 202 is a light-emitting surface, the third surface and the fourth surface Oppositely arranged, one or more bosses 11 are formed on the surface of the second substrate, and the third surface of one of the second LED chips is connected to an insulating and thermally conductive connecting glue 3 (hereinafter referred to as “connecting glue”). The top surface of the boss is connected.

Further, the aforementioned boss should match the size of the light-emitting area of the second LED chip and have a certain height.

Further, the aforementioned second LED chip 2 is a monolithic integrated high-power high-voltage flip-chip LED chip. The second LED chip 2 includes an electrode area and a light-emitting area. The electrode area is spaced apart from the light-emitting area, and the light-emitting area includes A plurality of unit cells capable of independently emitting light are arranged in series and/or in parallel, and the plurality of unit cells are electrically connected to the electrode area.

Please refer to FIG. 9, in the aforementioned second LED chip 2, each unit cell can be electrically connected through the interconnection metal layer 26 formed on the third surface of the second LED chip 2, in order to ensure the reliability of the electrical connection. An insulating dielectric layer 25 may also be provided on the third surface of the second LED chip 2. A typical second LED chip 2 may include a substrate 21 (such as a sapphire substrate) and an epitaxial structure formed on the substrate. The epitaxial structure may include an N-type GaN layer 22, a light-emitting region 23, and a P-type GaN layer 24 and so on.

The aforementioned unit cell is an independent and complete functional device unit formed by processing in the epitaxial structure, and the conductive semiconductor layers of any two unit cells are isolated to make any unit cell electrically independent; Each unit cell is electrically connected to form the monolithic integrated high-power high-voltage flip-chip LED chip.

Preferably, the substrate may be "wafer level", that is, the diameter of the substrate is more than 2 inches. Correspondingly, the monolithic integrated high-power high-voltage flip-chip LED chip can also be regarded as a wafer-level device.

The material of the aforementioned second substrate 1 includes aluminum nitride, silicon nitride, beryllium nitride, aluminum oxide, silicon carbide, etc., and is not limited thereto.

Preferably, the light-emitting surface of the aforementioned second LED chip 2 can also be covered with a phosphor layer 27 to realize the conversion of the light-emitting wavelength of the chip, for example, to realize a white light LED chip.

There are also conductive structures 12 formed by solder or silver paste distributed on the surface of the aforementioned second substrate 1 for electrical connection with the electrodes of the aforementioned chip 2. These conductive structures 12 can be electrically connected to an external power source via leads 13, and the same is To ensure the reliability of the electrical connection, an insulating layer 14 may also be provided on the surface of the second substrate 1.

When the aforementioned high-voltage flip-chip LED light source is manufactured, the aforementioned second LED chip can be attached to the second substrate 1. In order to ensure that there is no gap between the second LED chip 2 and the second substrate 1, it is necessary to make the connection glue slightly Overflow, but if the connecting glue flows to the conductive electrode, it will affect the electrical connection. In the existing LED packaging structure, it is generally considered to make a groove on the second substrate 1, but because the air in the groove cannot be discharged during the chip bonding, a large number of bubbles will be generated which seriously affects the heat dissipation uniformity of the chip. Therefore, the method of storing glue on the boss is adopted. When the chip is attached to the substrate, the gas is discharged to the surroundings, and the excess connecting glue flows down the side of the boss and gathers around the boss under the action of force, and at the same time, does not affect the electrical connection.

Further, please refer to FIG. 9 again. The groove-like structure formed between the unit cells in the second LED chip can also be used as a gas storage space. In this way, the second LED chip 2 is connected to the second LED chip 2 with a connecting glue. When the substrate 1 is connected, the gas in the connecting glue can be discharged into the gas storage space, reducing or eliminating bubbles that may exist therein, thereby further enhancing the reliability of the connection between the chip and the substrate.

For comparison, please refer to Figure 1b. In an existing flip-chip LED light source, the light-emitting surface of the chip 2'is a continuous plane, that is, there is no gas storage space for the second LED chip shown in Figure 9 Therefore, in its packaging structure, the gas in the connecting glue 3'cannot be released, and is distributed in the connecting glue in the form of bubbles 31'. This will affect the bonding strength of the chip and the substrate. The heat dissipation efficiency is greatly reduced.

Example 6

Please refer to FIG. 10, a high-voltage flip-chip LED light source, which has a structure similar to that of the foregoing embodiment 5. The difference is that: the foregoing second substrate 1 can be made of a thermally conductive metal material such as copper and aluminum. In the example, an additional layer of thermally conductive insulating ceramic is added as the thermally conductive insulating layer 4 on the boss. In this way, the choice of the second substrate 1 can be made more free, and thermal conductivity can be given priority, and the insulation of the connecting glue is not required to be considered, so that the thickness of the connecting glue is reduced, which is beneficial to heat conduction. The thermally conductive insulating ceramic may include aluminum nitride and the like, and is not limited thereto.

Example 7

Please refer to FIG. 11, a high-voltage flip-chip LED light source, which has a structure similar to that of the foregoing embodiment 5. The difference is that: the foregoing second substrate 1 can be made of thermally conductive metal materials such as copper and aluminum. For example, a dense thermally conductive insulating passivation layer 5 can be directly produced on the boss of the second substrate 1 as a thermally conductive insulating layer through a chemical reaction. The chemical reaction can be an oxidation reaction, etc., and is not limited to this. In this way, the choice of the second substrate can be more free, and thermal conductivity can be given priority. At the same time, there is no need to consider the insulation of the connecting glue, so that the thickness of the connecting glue is large. The reduction is beneficial to heat conduction, and the thickness of the passivation layer 5 can reach several microns, which can well meet the requirements of heat conduction and insulation. Of course, the aforementioned passivation layer can also be deposited on the surface of the second substrate by other chemical deposition, physical deposition, such as CVD, PECVD, PVD, ALD, etc. The material can include aluminum nitride, silicon nitride, beryllium nitride, Aluminum oxide, silicon carbide, etc. are not limited thereto.

Example 8

In the foregoing Embodiments 5 to 7, the light-emitting surface of the second LED chip 2 is pre-covered with a phosphor layer, so it can be regarded as a chip-type phosphor layer packaging structure. In this embodiment, another optimized solution can be adopted, that is, referring to FIG. 12, the second LED chip can be fabricated first; then the second chip 2 is pasted on the second substrate 1 with reference to the foregoing embodiment. The second chip 2 is electrically connected to the second substrate 1, and then a phosphor layer 28 is coated on the surface of the second chip, and then the leads are connected. So as to realize the so-called "substrate-type phosphor layer packaging structure." The advantages of this packaging method are: simple process and low cost.

Example 9

In this embodiment, another optimized solution can also be used, that is, as shown in FIG. 13, a hard conductive material 6 (metal sheet or metal wire) is added to the electrode area of the second chip 2, which is equivalent to the electrode , And then use silver paste or electrical welding material 7 to connect the hard conductive material 6 and the second substrate 1. The advantage of this method is to ensure the electrical connection between the second chip and the second substrate. When pasting the chip, there is no need to consider the problem of insulation between the chip and the substrate caused by the overflow of the connecting glue, and the distance between the electrode area of the chip and the light-emitting area is reduced, and the distance between Chip area utilization.

The aforementioned second LED chip 2 may have the structure shown in FIG. 14, in which the light-emitting area 203 and the electrode area 204 have a certain distance to ensure that the thermally conductive insulating layer material does not overflow to the electrode surface during packaging, causing the electrode to be disconnected, while ensuring that the solder does not overflow to emit light The light-emitting area 203 is composed of a number of the aforementioned unit cells, and the unit cells can adopt a parallel-series structure as shown in the figure. The feature of this structure is: if a single cell is short-circuited, the parallel stage will fail. Because the LED is driven by a constant current, the other stages of the chip work normally. If a single cell breaks, the remaining cells in the parallel stage will share the excess Current, this level works normally, so the chip as a whole can still work normally, this structure helps to improve the chip's anti-failure efficiency. In addition, in the structure shown in FIG. 14, the electrode area is a triangular structure, which is beneficial to increase the area of the light-emitting area and improve the utilization rate of the chip. The chip adopts monolithic integration technology without splitting and gold wire technology, which saves cost and improves Area utilization.

The aforementioned second LED chip 2 may also have the structure shown in Fig. 15 and Fig. 16; of course, the structure shown in Fig. 14 is the best, because the electrode area is designed as a triangle, which can effectively improve the area utilization of the chip and reduce the light emission. Maximize area area.

In the high-voltage flip-chip LED light source provided by the above embodiments of the present application, the second chip can be seamlessly combined with the second substrate, and the problem of overflow of the connecting glue to the conductive electrode can be avoided, thereby ensuring the effectiveness of the electrical connection , Can also enhance the uniformity of heat dissipation of the LED flip chip. At the same time, the second LED chip used is a monolithic integrated high-power high-voltage flip-chip LED chip, which has the characteristics of good stability and high failure resistance. The special position design of the electrode area and the light-emitting area can effectively increase the chip area The utilization rate maximizes the area of the light-emitting area, and also ensures that the thermally conductive insulating layer material does not overflow to the electrode surface during packaging, and that the solder does not overflow into the light-emitting area to cause a short circuit.

It should be understood that the above-mentioned embodiments only illustrate the technical ideas and features of the application, and their purpose is to enable those familiar with the technology to understand the content of the application and implement them accordingly, and cannot limit the protection scope of the application. All equivalent changes or modifications made according to the spirit and essence of this application shall be covered by the protection scope of this application.

Claims

A large-area LED light source structure, which is characterized by comprising a first substrate, a first LED chip, and a thermally conductive connection structure arranged between the first LED chip and the first substrate. The thermally conductive connection structure includes a plurality of An insulating thermal conductor, one end of the insulating thermal conductor is bonded to the first LED chip through an insulating and thermally conductive connecting glue, and the other end is thermally connected to the first substrate through a thermally conductive solder, thereby forming a gap between the first substrate and the first LED chip Multiple insulated and heat-conducting channels.
The large-area LED light source packaging structure according to claim 1, wherein the thermally conductive connection structure further comprises a plurality of metal thermal conductors that are electrically isolated from each other arranged at one end of at least one of the insulating thermal conductors, and the insulating thermal conductors One end of the body is thermally connected to the first LED chip through a plurality of metal heat conductors that are electrically isolated from each other.
The large-area LED light source packaging structure according to claim 2, wherein the metal heat conductor is island-shaped.
The large-area LED light source packaging structure according to any one of claims 1 to 3, wherein the shape of the insulating heat conductor includes a rectangular parallelepiped shape or a cylindrical shape.
The large-area LED light source packaging structure according to claim 1, wherein the first LED chip is a flip chip, and the first surface of the flip chip with electrodes is thermally connected to the first substrate via a thermally conductive connection structure , The second surface of the flip chip is a light-emitting surface, and the first surface and the second surface are arranged opposite to each other.
The large-area LED light source packaging structure according to claim 5, wherein an insulating layer is provided on the surface of the first substrate, a conductive layer is provided on the insulating layer, and the electrodes of the first LED chip are hardened The conductive material or conductive lead is electrically connected to the conductive layer.
The large-area LED light source packaging structure according to claim 1, wherein the first LED chip is a front-mounted chip, the second surface of the front-mounted chip is thermally connected to the first substrate through a thermally conductive connection structure, and the front-mounted The first surface of the chip is a light-emitting surface and has electrodes, and the first surface and the second surface are arranged opposite to each other.
The large-area LED light source packaging structure according to claim 7, wherein an insulating layer is provided on the surface of the first substrate, a conductive layer is provided on the insulating layer, and the electrodes of the first LED chip are hardened The conductive material or conductive lead is electrically connected to the conductive layer.
The large-area LED light source packaging structure according to claim 1, wherein the first LED chip has a warped structure as a whole, and the distribution form of the plurality of insulating thermal conductors matches the warped structure.
A method for packaging a large area LED light source, which is characterized in that it comprises:

Bonding one end of a plurality of insulating thermal conductors spaced apart from each other to the first LED chip via an insulating and thermally conductive connecting glue, so that the distribution form of the plurality of insulating thermal conductors matches the overall structure of the first LED chip; and

The other ends of the plurality of insulating thermal conductors are thermally connected to the first substrate via a thermally conductive solder, thereby forming a plurality of insulating and thermally conductive channels between the first substrate and the first LED chip.
A high-voltage flip-chip LED light source, characterized by comprising a second substrate and a second LED chip, wherein the second substrate is a thermally conductive substrate, and the second LED chip is a high-voltage flip-chip LED chip;

The third surface of the second LED chip has electrodes, the fourth surface is a light-emitting surface, the third surface is opposite to the fourth surface, and at least one boss is formed on the surface of the second substrate, at least one of which is The third surface of the second LED chip is connected to the top surface of a boss through an insulating and thermally conductive connecting glue.
The high-voltage flip-chip LED light source according to claim 11, wherein the top surface of the boss is further covered with a thermally conductive insulating layer, and the third surface of the second LED chip is connected to the The thermally conductive insulating layer is connected; wherein the thermally conductive insulating layer is formed of a thermally conductive insulating material, and the thermally conductive insulating layer is transferred from the outside, or the thermally conductive insulating layer is at least integrally formed on the top of the boss Surface.
The high-voltage flip-chip LED light source according to claim 12, wherein the material of the second substrate includes an electrically and thermally conductive metal material, and the electrically and thermally conductive metal material includes copper or aluminum.
The high-voltage flip-chip LED light source according to claim 12, wherein the thermally conductive insulating layer is a dense thermally conductive insulating passivation layer formed by chemically treating the surface of the second substrate.
The high-voltage flip-chip LED light source according to claim 11, wherein the entire second substrate or the boss is formed of a thermally conductive insulating material.
The high-voltage flip-chip LED light source according to claim 12 or 15, characterized in that: the thermally conductive insulating material includes any one of oxide, nitride, and carbide; the oxide includes aluminum oxide or copper oxide, The nitride includes aluminum nitride, silicon nitride, or beryllium nitride, and the carbide includes silicon carbide.
The high-voltage flip-chip LED light source according to claim 11, wherein the second LED chip is a monolithic integrated high-power high-voltage flip-chip LED chip, the second LED chip includes an electrode area and a light-emitting area, and The electrode area and the light-emitting area are arranged at intervals, and the light-emitting area includes a plurality of unit cells capable of independently emitting light, the plurality of unit cells are arranged in series and/or in parallel, and the plurality of unit cells are electrically connected to the electrode area.
The high-voltage flip-chip LED light source according to claim 17, wherein the second LED chip has more than one set of electrode areas, each set of electrode areas includes two symmetrically arranged electrode areas, and the electrode areas are triangular Structure or linear structure; and/or, a gas storage space is also distributed in the second LED chip, and the gas storage space includes a groove-shaped structure formed between unit cells; and/or, the second LED A hard conductive material is combined on the electrode area of the chip, and the hard conductive material is electrically connected to the conductive circuit on the substrate through silver paste or electrical welding material.
The high-voltage flip-chip LED light source according to claim 18, wherein the second LED chip has a set of electrode areas, and the set of electrode areas are two symmetrically arranged triangular electrode areas.
The high-voltage flip-chip LED light source according to claim 17, wherein the distance between the light-emitting area and the electrode area satisfies the following conditions: the third surface of the second LED chip is connected to the During the process of connecting the top surface of the boss, the non-insulating and thermally conductive connecting glue overflows to the surface of the electrode area.