CN112466858A

CN112466858A - Large-area LED light source packaging structure and packaging method

Info

Publication number: CN112466858A
Application number: CN201910866077.XA
Authority: CN
Inventors: 唐文婷; 蔡勇
Original assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Current assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Priority date: 2019-09-09
Filing date: 2019-09-09
Publication date: 2021-03-09
Anticipated expiration: 2039-09-09
Also published as: CN112466858B

Abstract

The invention discloses a large-area LED light source packaging structure and a packaging method. The large-area LED light source packaging structure includes a substrate, an LED chip, and a thermally conductive connection structure disposed between the LED chip and the substrate. The thermally conductive connection structure includes a plurality of insulating thermal conductors spaced from each other, and one end of the insulating thermal conductor is The insulating and heat-conducting connecting glue is bonded to the LED chip, and the other end is heat-conductively connected to the substrate through the heat-conducting solder, thereby forming a plurality of insulating and heat-conducting channels between the substrate and the LED chip. In the large-area LED light source package structure provided by the present invention, the distribution shape of the plurality of insulating heat-conducting bodies matches the warping structure of the LED chip, and one end of the insulating heat-conducting body is pasted on the substrate by the heat-conducting solder, thereby forming a good insulating and heat-conducting channel. The problem of uneven heat dissipation caused by the warpage of the large-area LED chip is solved; because the contact area between a single insulating thermal conductor and the LED chip is small, the thermal expansion stress can be reduced, and the reliability of the device can be improved.

Description

Large-area LED light source packaging structure and packaging method

Technical Field

The invention relates to an LED light source packaging structure, in particular to a large-area LED light source packaging structure and a packaging method, and belongs to the technical field of semiconductors.

Background

Along with the increase of the area of the LED chip, the warping degree of the chip is increased, and the distances between each part of the chip and the substrate are different, so that the thermal resistance of each part is different, the heat dissipation is uneven, and the performance of a device is affected.

Disclosure of Invention

The invention mainly aims to provide a large-area LED light source packaging structure and a packaging method, so as to overcome the defects in the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

the embodiment of the invention provides a large-area LED light source packaging structure which comprises a substrate, an LED chip and a heat conduction connecting structure arranged between the LED chip and the substrate, wherein the heat conduction connecting structure comprises a plurality of insulating heat conductors arranged at intervals, one end of each insulating heat conductor is bonded with the LED chip through insulating heat conduction connecting glue, and the other end of each insulating heat conductor is in heat conduction connection with the substrate through heat conduction welding flux, so that a plurality of insulating heat conduction channels are formed between the substrate and the LED chip.

Furthermore, the heat-conducting connecting structure further comprises a plurality of metal heat conductors which are electrically isolated from each other and arranged at one end of at least one insulating heat conductor, and one end of the insulating heat conductor is in heat-conducting connection with the LED chip through the plurality of metal heat conductors which are electrically isolated from each other.

Further, the metal heat conductor is island-shaped.

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

In some specific embodiments, the LED chip is a flip chip, the first surface of the flip chip having the electrode is connected to the substrate through a heat-conducting connection structure, the second surface of the flip chip is a light-emitting surface, and the first surface and the second surface are disposed opposite to each other.

Further, an insulating layer is arranged on the surface of the substrate, a conducting layer is arranged on the insulating layer, and the electrode of the LED chip is electrically connected with the conducting layer through a hard conducting material or a conducting lead.

In some specific embodiments, the LED chip is a flip chip, one end of the insulating heat conductor is connected to the LED chip through a plurality of metal heat conductors electrically isolated from each other in a heat conducting manner, a distance c between two adjacent metal heat conductors is greater than or equal to 1 μm, at least one pair of P-electrode and N-electrode of the LED chip is connected to the front surface of the substrate through the plurality of metal heat conductors arranged at intervals in a heat conducting manner, a maximum dimension a of any one metal heat conductor in a direction parallel to a side surface of the LED chip having the electrode is smaller than a minimum distance d between the P-electrode and the N-electrode, and d > a is greater than or equal to 2 μm.

In some specific embodiments, the LED chip is a front-mounted chip, the second surface of the front-mounted chip is connected to the substrate through a heat-conducting connection structure, the first surface of the front-mounted chip is a light-emitting surface and has an electrode, and the first surface and the second surface are disposed opposite to each other.

Furthermore, the whole LED chip is of a warping structure, and the distribution form of the plurality of insulating heat conductors is matched with the warping structure.

The embodiment of the invention also provides a large-area LED light source packaging method, which comprises the following steps:

bonding one ends of a plurality of insulated heat conductors which are arranged at intervals with each other with an LED chip through insulated heat conduction connecting glue, so that the distribution form of the plurality of insulated heat conductors is matched with the integral structure of the LED chip; and

and connecting the other ends of the plurality of insulating heat conductors with the substrate in a heat conduction manner through heat conduction welding materials, so that a plurality of insulating heat conduction channels are formed between the substrate and the LED chip.

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

Compared with the prior art, the large-area LED light source packaging structure provided by the embodiment of the invention is characterized in that a plurality of insulating heat conductors are arranged between the substrate and the high-voltage, high-power and large-size LED chip, wherein the distribution form of the plurality of insulating heat conductors is matched with the warping structure of the LED chip, one end of each insulating heat conductor is stuck on the substrate by the heat-conducting solder, so that a good insulating heat-conducting channel is formed, and the problem of uneven heat dissipation caused by warping of the large-area LED chip is well solved; in addition, the contact area of the single insulating heat conductor and the LED chip is small, so that the thermal expansion stress can be reduced, and the reliability of the device is improved.

Drawings

FIG. 1 is a schematic structural diagram of a large-area LED light source package structure according to an exemplary embodiment of the present invention;

fig. 2 is a schematic structural diagram of a large-area LED light source package structure in embodiment 1 of the present invention;

fig. 3 is a schematic structural diagram of a large-area LED light source package structure in embodiment 2 of the present invention;

fig. 4 is a schematic structural diagram of a large-area LED light source package structure in embodiment 3 of the present invention;

fig. 5 is a schematic structural diagram of a large-area LED light source package structure in embodiment 4 of the present invention;

fig. 6 is a schematic structural diagram of a connection portion between a chip and a metal heat conductor in a large-area LED light source package structure in embodiment 3 or 4 of the present invention.

Detailed Description

In view of the deficiencies in the prior art, the inventors of the present invention have made extensive studies and extensive practices to provide technical solutions of the present invention. The technical solution, its implementation and principles, etc. will be further explained as follows.

Example 1

Referring to fig. 1 and 2, a large-area LED light source package structure includes a substrate 10, an LED chip 20, and a heat conducting connection structure 30 disposed between the substrate 10 and the LED chip 20, wherein the heat conducting connection structure 30 includes a plurality of insulating heat conductors 31 disposed at intervals, one end of each insulating heat conductor 31 is bonded to the LED chip 20 through an insulating heat conducting connection glue 40, and the other end is connected to the substrate 10 through a heat conducting solder 50, so as to form a plurality of insulating heat conducting channels between the substrate 10 and the LED chip 20; the whole LED chip is of a warping structure, the distribution form of the plurality of insulating heat conductors 31 is matched with the warping structure, namely one end of each of the plurality of insulating heat conductors 31 forms an arc surface matched with the surface of the LED chip; and an electrode lead-out structure is further arranged on the substrate 10, and the electrode of the LED chip is electrically connected with the electrode lead-out structure.

Specifically, the LED chip 20 is a flip chip, the LED chip 20 has a first surface and a second surface opposite to each other, an electrode is disposed on the first surface of the LED chip 20, the LED chip 20 is connected and bonded to the insulating heat conductor 31 through the first surface having the electrode, the electrode lead structure includes a solder 63 and a pad 65, the solder 63 and the pad 65 are electrically connected through the conductive layer 51, and the solder 63 is electrically connected to the electrode of the LED chip through a hard conductive material (e.g., a conductive metal sheet) 64; an insulating layer 62 is provided between the electrode lead-out structure and the substrate 10, and an insulating layer 61 is further provided on the upper surface of the conductive layer 51.

Specifically, the structure or shape of the insulating heat conductor 31 is a rectangular parallelepiped, a square, a cylinder, a truncated cone, or a prism, and the insulating heat conductors 31 may have different lengths.

Specifically, the combination manner of the insulating heat conductor 31 and the LED chip 20 may be insulating connection adhesive bonding, self-aligned isolation technology, or the like; the insulating heat conductor 31 and the substrate 10 may be bonded by reflow soldering, silver paste, soldering, or the like.

The substrate 10 may be a metal substrate or a non-metal substrate, the metal substrate may be made of metal with good thermal conductivity such as aluminum or copper, and the non-metal substrate may be made of ceramic.

More specifically, one end of the insulating heat conductor 31 is adhered to the surface of the high-voltage, high-power and large-size LED chip in a self-adaptive manner, one end of each of the insulating heat conductors 31 forms a curved surface adapted to the surface of the LED chip, and then the other end of each of the insulating heat conductors 31 is adhered to the substrate through the heat-conducting solder, so that a good insulating heat-conducting channel is formed, and the problem of uneven heat dissipation caused by the warping of the large-area LED chip is well solved; in addition, the contact area of the single insulating heat conductor and the LED chip is small, so that the thermal expansion stress can be reduced, and the reliability of the device is improved.

Example 2

Referring to fig. 1 and fig. 3, the structure of the large-area LED light source package structure in the present embodiment is substantially the same as that of the large-area LED light source package structure in embodiment 1, except that: the LED chip 20 in this embodiment is a front-mounted chip, the insulating heat conductor 31 is connected to the second surface of the LED chip 20, and the electrodes of the LED chip are electrically connected to the solder 63 by using soft conductive connecting wires.

Example 3

Referring to fig. 4, a large-area LED light source package structure includes a substrate 10, an LED chip 20, and a heat conducting connection structure 30 disposed between the substrate 10 and the LED chip 20, where the heat conducting connection structure 30 includes a plurality of insulating heat conductors 31 disposed at intervals, one end of the insulating heat conductor 31 is disposed with a plurality of metal heat conductors 32 electrically isolated from each other, one end of the metal heat conductor 32 is welded to the LED chip 20, and the other end of the insulating heat conductor 31 is connected to the substrate 10 through a heat conducting solder 50 in a heat conducting manner, so as to form a plurality of insulating heat conducting channels between the substrate 10 and the LED chip 20 (each insulating heat conducting channel in this embodiment mainly includes an insulating heat conductor and a plurality of metal heat conductors disposed at one end of the insulating heat conductor); the whole LED chip is of a warping structure, and the distribution forms of the plurality of insulating heat conductors 31 and the plurality of metal heat conductors 32 are matched with the warping structure; and an electrode lead-out structure is further arranged on the substrate 10, and the electrode of the LED chip is electrically connected with the electrode lead-out structure.

Specifically, the LED chip in this embodiment is a flip chip, the LED chip 20 has a first surface and a second surface which are oppositely arranged, an electrode is arranged on the first surface of the LED chip 20, the electrode lead-out structure includes a solder 63 and a pad 65, the solder 63 and the pad 65 are electrically connected through a conductive layer 51, and the solder 63 is electrically connected with the electrode of the LED chip through a hard conductive material (conductive metal sheet) 64; an insulating layer 62 is provided between the electrode lead-out structure and the substrate 10, and an insulating layer 61 is further provided on the upper surface of the conductive layer 51.

More specifically, referring to fig. 6, the 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, which are sequentially stacked, wherein a P electrode 26 and an N electrode 27 are disposed on the insulating layer 25 at an interval, a portion of the P electrode 26 penetrates through the insulating layer 25 and is connected to the P-type GaN layer 24, a portion of the N electrode 27 continuously penetrates through the insulating layer 25, the P-type GaN layer 24, and the active layer 23 and is disposed in the N-type GaN layer 22, a distance between the P electrode 26 and the N electrode 27 is d, the P electrode 26 and the N electrode 27 are respectively connected to at least one metal heat conductor 32 in a heat conduction manner, and at least the P electrode 26 and the N electrode 27 are further electrically connected to an electrode lead-out structure.

Specifically, the metal heat conductors 32 may be rectangular parallelepiped structures, the width of each metal heat conductor is a, the height of each metal heat conductor is b, the distance between two adjacent metal heat conductors 32 is c, wherein a is greater than or equal to 2 μm, c is greater than or equal to 1 μm, and the distance d between the P electrode 26 and the N electrode 27 is greater than the width a of the metal heat conductors 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 is understood that the distance between the P electrode and the N electrode and the width of the metal heat conductor are the same distance in the reference direction, which may be the width direction of the metal heat conductor; when the metal heat conductor is in a cylindrical or circular truncated cone structure, the predetermined direction may be a direction parallel to a side surface of the LED chip having the electrode.

Because the metal heat conductors are electrically isolated and the width of the metal heat conductors is smaller than the distance between the P, N electrodes, the short circuit problem cannot be caused, the requirement on the alignment precision of equipment is further reduced, the alignment error is half of the area of the P, N electrodes, and the cost is reduced; the contact area of the 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 improved.

Specifically, the structure or shape of the insulating heat conductor 31 is a rectangular parallelepiped, a square, a cylinder, a truncated cone, or a prism, and the plurality of insulating heat conductors 31 may have the same length.

Specifically, the metal heat conductor 32 and the LED chip 20 may be bonded by soldering, adhesive bonding, self-aligned isolation technique, etc.; the insulating heat conductor 31 and the substrate 10 may be bonded by reflow soldering, silver paste, soldering, or the like. Self-aligned isolation technique: because the metal islands (namely the island-shaped metal heat conductors) which are electrically isolated and have the size smaller than the electrode spacing of the chip are arranged on the substrate, when the flip chip is welded with the substrate, the chip electrode and the metal islands can realize self-alignment welding of the chip without accurate alignment, and no short circuit exists between the electrodes. The substrate 10 may be a metal substrate or a non-metal substrate, the metal substrate may be made of metal with good thermal conductivity such as aluminum or copper, and the non-metal substrate may be made of ceramic.

More specifically, a plurality of metal heat conductors 32 may be arranged at one end of each insulating heat conductor 31 in advance, then one end of each metal heat conductor is combined with the surface of the high-voltage, high-power and large-size LED chip in a self-adaptive manner, one end of each metal heat conductor 32 forms a curved surface adapted to the surface of the LED chip, and then the other end of each insulating heat conductor 31 is adhered to the substrate through a heat-conducting solder, so as to form a good insulating heat-conducting channel, thereby well solving the problem of uneven heat dissipation caused by the warping of the large-area LED chip; in addition, the contact area of the single insulating heat conductor and the LED chip is small, so that the thermal expansion stress can be reduced, and the reliability of the device is improved.

Example 4

Referring to fig. 5, the structure of the large-area LED light source package structure in the present embodiment is substantially the same as that of the large-area LED light source package structure in embodiment 3, except that: the LED chip 20 in this embodiment is a front-mounted chip, one end of the metal heat conductor 32 is connected and bonded to the second surface of the LED chip 20 without the electrode, and the electrode of the LED chip 20 is electrically connected to the solder 63 by a soft conductive connecting wire.

In addition, the insulated conductors 31 used in examples 1 to 4 are all insulated heat conductors of equal length; in some specific embodiments, an insulating heat conductor with unequal length may be used, in which one end of the insulating heat conductors 31 is first connected to the substrate, and the other end of the insulating heat conductors 31 (where a metal heat conductor is provided, one end of the metal heat conductor) is located on a curved surface matching the surface of the chip, and then the chip is connected to the insulating heat conductor 31 (where a metal heat conductor is provided, the metal heat conductor is provided).

Or, in other specific embodiments, a substrate having the same warping structure and matched with the warping structure of the LED chip may be further used, and an insulating heat conductor or an insulating heat conductor and a metal heat conductor are disposed and connected between the LED chip and the substrate to form a heat conducting channel, so as to solve the problem of uneven heat dissipation caused by warping of the large-area LED chip.

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

It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, which are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and therefore, the protection scope of the present invention is not limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. The large-area LED light source packaging structure is characterized by comprising a substrate, an LED chip and a heat conduction connecting structure arranged between the LED chip and the substrate, wherein the heat conduction connecting structure comprises a plurality of insulating heat conductors arranged at intervals, one end of each insulating heat conductor is bonded with the LED chip through insulating heat conduction connecting glue, the other end of each insulating heat conductor is in heat conduction connection with the substrate through heat conduction welding flux, and therefore a plurality of insulating heat conduction channels are formed between the substrate and the LED chip.

2. The large area LED light source package structure of claim 1, wherein: the heat conduction connecting structure further comprises a plurality of metal heat conductors which are electrically isolated from each other and arranged at one end of at least one insulating heat conductor, and one end of the insulating heat conductor is in heat conduction connection with the LED chip through the plurality of metal heat conductors which are electrically isolated from each other.

3. The large area LED light source package structure of claim 2, wherein: the metal heat conductor is in an island shape.

4. The large area LED light source package structure of any one of claims 1-3, wherein: the shape of the insulating heat conductor comprises a cuboid shape or a column shape.

5. The large area LED light source package structure of claim 1, wherein: the LED chip is the flip chip, the first surface that the flip chip has the electrode is connected with base plate heat conduction through heat conduction connection structure, the second surface of flip chip is for going out the plain noodles, first surface and second surface set up back to back.

6. The large area LED light source package structure of claim 5, wherein: the LED chip comprises a substrate and is characterized in that an insulating layer is arranged on the surface of the substrate, a conducting layer is arranged on the insulating layer, and an electrode of the LED chip is electrically connected with the conducting layer through a hard conducting material or a conducting lead.

7. The large area LED light source package structure of claim 1, wherein: the LED chip is a front-mounted chip, the second surface of the front-mounted chip is in heat conduction connection with the substrate through a heat conduction connection structure, the first surface of the front-mounted chip is a light-emitting surface and is provided with an electrode, and the first surface and the second surface are arranged back to back.

8. The large area LED light source package structure of claim 7, wherein: the LED chip comprises a substrate and is characterized in that an insulating layer is arranged on the surface of the substrate, a conducting layer is arranged on the insulating layer, and an electrode of the LED chip is electrically connected with the conducting layer through a hard conducting material or a conducting lead.

9. The large area LED light source package structure of claim 1, wherein: the whole LED chip is of a warping structure, and the distribution form of the plurality of insulating heat conductors is matched with the warping structure.

10. A method for packaging a large-area LED light source is characterized by comprising the following steps: