CN209804710U

CN209804710U - Fan-out type LED packaging structure and electronic display screen

Info

Publication number: CN209804710U
Application number: CN201920354044.2U
Authority: CN
Inventors: 陈彦亨; 林正忠
Original assignee: Zhongxin Changdian Semiconductor (jiangyin) Co Ltd
Current assignee: SJ Semiconductor Jiangyin Corp
Priority date: 2019-03-20
Filing date: 2019-03-20
Publication date: 2019-12-17
Anticipated expiration: 2029-03-20

Abstract

The utility model provides a fan-out type LED's packaging structure and electronic display screen, the structure includes: a rewiring layer including a first surface and a second surface; the LED chip is provided with a metal lead post on an electrode and packaged by a first packaging layer, and the metal lead post is exposed out of the first packaging layer and connected with the rewiring layer; the second packaging layer wraps the side face of the LED chip, and the light-emitting surface of the LED chip is exposed out of the second packaging layer; and a metal bump formed on the first surface of the rewiring layer. The utility model discloses a make rewiring layer and metal convex block on the LED chip after the encapsulation, realize the fan-out encapsulation of LED chip, the utility model discloses an encapsulation structure and packaging method can satisfy Micro LED ultrahigh resolution ratio encapsulation demand, realize the LED encapsulation of little line width encapsulation and satisfy system formula.

Description

Fan-out type LED packaging structure and electronic display screen

Technical Field

The utility model belongs to the semiconductor package field especially relates to a fan-out type LED's packaging structure and packaging method.

Background

The LED technology is rapidly developed, the RGB LED packaging size is smaller and smaller, the arrangement distance of LED particles is effectively reduced, and the resolution of an electronic display screen is promoted to be improved upwards. In large-size display products, compared with liquid crystal LED panels, the liquid crystal LED panels employ blue LEDs, which are only used as backlight sources and have no color mixing effect, and the electronic display panels directly mix colors through RGB LEDs, so that the electronic display panels have better color display effect compared with liquid crystal LED panels. However, in the past, the RGB LED packages have too large size, and in addition to heat dissipation considerations, the arrangement pitch between the packages is large and the density is low, so that the resolution of the electronic display screen is relatively low, and the electronic display screen is suitable for remote viewing.

The main application field of electronic display screen is mostly outdoor, like advertisement bill-board, gymnasium outer wall etc. and some indoor squares also have the use, like railway station, TV studio, lecture hall etc.. With the increasing resolution of electronic display screens, users can view and admire at a closer distance, so for the indoor commercial market, the liquid crystal LED panels are spliced into a large screen, and a gap is left between the two panels, which is not considered to lead in the electronic display screen, and the electronic display screen has more cost competitiveness in large-size display products.

The packaging mode of the LED electronic display screen device mainly comprises a dot matrix module, a direct insertion type, a sub-surface paste, a surface paste three-in-one, a COB (chip on board), a Micro LED and the like, and different packaging modes respectively have advantages and disadvantages and are suitable for different LED electronic display screen device application fields. Accordingly, LED electronic displays have also undergone an evolution from single color (e.g., single red, single green, single yellow, etc.), dual color, and the current mainstream RGB full color, from early use primarily outdoors to the current small pitch indoors, from low resolution toward wide color gamut, high resolution. These different packaging methods not only promote the progress of LED electronic displays, but also are a process of continuous self-innovation.

The key to improving the resolution of the LED electronic display screen is the rgbd packaging size, and how to reduce the rgbd packaging size is a technical difficulty faced in the art.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a fan-out LED package structure and method to realize a novel LED package structure and method, which can satisfy the requirement of Micro LED ultra-high resolution package, realize small line width package and satisfy the system type LED package.

To achieve the above and other related objects, the present invention provides a package structure of fan-out LED, comprising: a rewiring layer including a first side and an opposing second side; the LED chip is positioned on the second surface of the rewiring layer, a metal lead post is arranged on an electrode of the LED chip and is packaged by a first packaging layer, and the metal lead post is exposed out of the first packaging layer and is connected with the rewiring layer; the second packaging layer wraps the side face of the LED chip, and the light-emitting surface of the LED chip is exposed out of the second packaging layer; and the metal bump is formed on the first surface of the rewiring layer so as to realize the electrical leading-out of the LED chip through the rewiring layer.

Optionally, the LED chip comprises an RGB three primary color LED chip.

Optionally, the LED chips are arranged in an array on the second surface of the redistribution layer.

Optionally, the material of the metal lead post comprises one of copper, gold and silver.

Optionally, the material of the second encapsulation layer includes one of polyimide, silicone, and epoxy resin.

Optionally, the metal bump comprises one of a tin solder, a silver solder, and a gold-tin alloy solder.

The utility model also provides an electronic display screen, electronic display screen contains as above fan-out type LED's packaging structure.

Optionally, the dot pitch of the electronic display screen is not greater than 0.5 mm.

The utility model also provides a wafer level fan-out type LED's packaging method, packaging method includes the step: 1) providing an LED wafer, wherein the first surface of the LED wafer is provided with an electrode, and a metal lead post is formed on the electrode; 2) packaging the metal lead posts by using a first packaging layer, and exposing the metal lead posts to the first packaging layer; 3) cutting the LED wafer to obtain independent LED chips; 4) providing a supporting substrate, and forming a separation layer on the supporting substrate; 5) fixing the LED chip on the separation layer, wherein the metal lead column of the LED chip faces away from the separation layer; 6) packaging the LED chip by using a second packaging layer, and exposing the metal lead post on the second packaging layer; 7) manufacturing a rewiring layer on the second packaging layer, wherein a first surface of the rewiring layer is connected with the metal lead post; 8) forming a metal bump on the second surface of the rewiring layer to realize the electrical leading-out of the LED chip; 9) and peeling the LED chip and the support substrate based on the separation layer to expose the second packaging layer and the LED chip.

Optionally, the LED chip comprises an RGB three primary color LED chip.

Optionally, the LED chips in step 5) are arranged and fixed on the separation layer in an array.

Optionally, the support base comprises one of a glass substrate, a metal substrate, a semiconductor substrate, a polymer substrate, and a ceramic substrate.

Optionally, in the step 1), the metal lead post is formed on the electrode of the LED wafer by using a wire bonding process.

optionally, the separation layer includes a light-to-heat conversion layer, and step 9) irradiates the light-to-heat conversion layer with laser light to separate the light-to-heat conversion layer from the second encapsulation layer and the supporting substrate, thereby peeling the rewiring layer and the supporting substrate.

Optionally, the method for encapsulating the LED chip with the second encapsulation layer includes one of compression molding, transfer molding, liquid encapsulation molding, vacuum lamination, and spin coating, and the material of the second encapsulation layer includes one of polyimide, silicone, and epoxy resin.

Optionally, a step of cutting is further included to obtain a package structure of the individual fan-out LEDs.

As described above, the utility model discloses a fan-out type LED's packaging structure and encapsulation method has following beneficial effect:

The utility model provides a novel packaging structure and packaging method of LED of wafer level fan-out type, through make rewiring layer and metal convex block on the LED chip after the encapsulation, realize the fan-out encapsulation of LED chip, the utility model discloses a packaging structure and packaging method can satisfy Micro LED ultrahigh resolution encapsulation demand, realize the encapsulation of small-width and satisfy the LED encapsulation of system formula.

The utility model discloses a metal pin direct preparation on the electrode of LED wafer, the alignment that can be convenient for metal pin and electrode on the one hand is connected, can be convenient for follow-up and rewiring layer's being connected through this metal pin simultaneously, and on the other hand can avoid the pollution of electrode, guarantees the LED chip is connected with rewiring layer's good.

drawings

Fig. 1 to fig. 14 are schematic structural diagrams of steps of the packaging method of the fan-out LED of the present invention, wherein fig. 14 is a schematic diagram of the packaging structure of the fan-out LED of the present invention.

description of the element reference numerals

101 supporting substrate

102 separating layers

103 second encapsulation layer

20 LED wafer

22 LED chip

201 red light emitting unit

202 green light-emitting unit

203 blue light emitting unit

204 electrode

205 metal lead post

206 first encapsulation layer

40 rewiring layer

401 dielectric layer

402 metal wiring layer

501 metal bump

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can also be implemented or applied through other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structure are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

in the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and only the components related to the present invention are shown in the drawings rather than being drawn according to the number, shape and size of the components in actual implementation, and the form, amount and ratio of the components in actual implementation may be changed at will, and the layout of the components may be more complicated.

As shown in fig. 1 to 14, the present embodiment provides a method for packaging a wafer-level fan-out LED, the method comprising:

As shown in fig. 1-2, step 1) is performed first to provide an LED wafer, where a first surface of the LED wafer has an electrode, and a metal lead post is formed on the electrode.

For example, a wire bonding process may be used to form the metal lead posts 205 on the electrodes of the LED wafer 20. The metal lead post 205 may be made of one of copper, gold, and silver. The utility model discloses a metal pin direct preparation on the electrode of LED wafer, the alignment that can be convenient for metal pin and electrode on the one hand is connected, can be convenient for follow-up and rewiring layer's being connected through this metal pin simultaneously, and on the other hand can avoid the pollution of electrode, guarantees the LED chip is connected with rewiring layer's good.

As shown in fig. 3, step 2) is then performed to package the metal lead studs with a first package layer, and expose the metal lead studs on the first package layer.

As an example, the method for encapsulating the metal lead post 205 with the first encapsulation layer 206 includes one of compression molding, transfer molding, liquid encapsulation, vacuum lamination, and spin coating, and the material of the first encapsulation layer 206 includes one of polyimide, silicone, and epoxy.

Then, the method further includes the step of thinning the first package layer 206 and exposing the metal lead post 205 to the first package layer 206.

As shown in fig. 4, step 3) is then performed to cut the LED wafer to obtain individual LED chips.

In this embodiment, the LED wafer 20 includes an RGB three-primary-color LED wafer 20, the LED wafer surface has electrodes, the RGB three-primary-color LED wafer 20 includes a plurality of RGB three-primary-color LED chips 21, and the plurality of independent LED chips 21 are obtained by performing a cutting process, such as laser cutting or mechanical cutting, on the LED wafer 21.

The RGB three-primary-color LED chip 21 includes a red light emitting unit 201, a green light emitting unit 202, and a blue light emitting unit 203, the RGB three-primary-color LED chip 21 has an electrode 204, the electrode 204 is electrically connected to the red light emitting unit 201, the green light emitting unit 202, and the blue light emitting unit 203, the red light emitting unit 201, the green light emitting unit 202, and the blue light emitting unit 203 emit light by applying a suitable voltage to the electrode 204, and the red light emitting unit 201, the green light emitting unit 202, and the blue light emitting unit 203 may emit light simultaneously or selectively.

As shown in fig. 5 to 6, step 4) is performed to provide a supporting substrate 101, and a separation layer 102 is formed on the supporting substrate 101.

The support base 101 includes one of a glass substrate, a metal substrate, a semiconductor substrate, a polymer substrate, and a ceramic substrate, as an example. In this embodiment, the supporting substrate 101 is a glass substrate, which has a low cost, is easy to form the separation layer 102 on the surface thereof, and can reduce the difficulty of the subsequent stripping process.

As an example, the separation layer 102 includes a light-to-heat conversion Layer (LTHC), and is formed on the supporting substrate 101 by a spin coating process and then cured by a curing process. The light-heat conversion Layer (LTHC) has stable performance and smooth surface, is beneficial to obtaining flatness subsequently, and has lower stripping difficulty in the subsequent stripping process.

As shown in fig. 7, step 5) is then performed to fix the LED chip 21 to the separation layer 102, with the electrode 204 of the LED chip 21 facing away from the separation layer 102.

The RGB three-primary-color LED chips 21 are fixed on the separation layer 102 in an array, the array may be a rectangular array, a triangular array, etc., and an appropriate arrangement may be selected according to the requirement of the light emitting lattice, which is not limited to the examples listed here.

As shown in fig. 8 to 9, step 6) is performed next, the LED chip 21 is packaged by using the second packaging layer 103, and the metal lead stud 205 is exposed from the second packaging layer 103.

As an example, the method for encapsulating the LED chip 21 with the second encapsulation layer 103 includes one of compression molding, transfer molding, liquid encapsulation molding, vacuum lamination, and spin coating, and the material of the second encapsulation layer 103 includes one of polyimide, silicone, and epoxy. The material of the second packaging layer 103 may be the same as or different from the first packaging layer 206, and may be selected according to actual requirements.

Then, the method further includes the step of thinning the second package layer 103 and exposing the metal lead post 205 to the second package layer 103.

As shown in fig. 10, step 7) is performed next, so as to fabricate a redistribution layer 40 on the second package layer 103, where a first surface of the redistribution layer 40 is connected to the metal lead post 205.

The redistribution layer 40 includes a plurality of dielectric layers 401 and a plurality of metal wiring layers 402 arranged according to a pattern requirement, and two adjacent metal wiring layers 402 are connected by a conductive plug. By the rewiring layer 40, system-in-package of the LED chips 21 can be realized, the pitch of the LED chips 21 can be made very small, and the resolution is improved. The material of the dielectric layer 401 includes one or a combination of more than two of epoxy resin, silica gel, PI, PBO, BCB, silicon oxide, phosphorosilicate glass and fluorine-containing glass. The material of the dielectric layer 401 may be PI (polyimide), so as to further reduce the process difficulty and the process cost. The material of the metal wiring layer 402 includes one or a combination of two or more of copper, aluminum, nickel, gold, silver, and titanium. In this embodiment, the metal wiring layer 402 is made of copper.

As shown in fig. 11, step 8) is then performed to form a metal bump 501 on the second surface of the redistribution layer 40, so as to electrically extract the LED chip 21 through the redistribution layer 40.

For example, the metal bump 501 may be one of a solder, a silver solder, and a gold-tin alloy solder.

As shown in fig. 12, step 9) is performed next, the LED chip 21, the second encapsulating layer 103, and the supporting substrate 101 are peeled off from the separation layer 102, and the second encapsulating layer 103 and the LED chip 21 are exposed.

Specifically, the separation layer 102 is selected as a light-to-heat conversion layer, and laser is used to irradiate the light-to-heat conversion layer, so that the light-to-heat conversion layer is separated from the second encapsulation layer 103, the LED chip 21, and the supporting substrate 101, and the LED chip 21 and the supporting substrate 101 are peeled off.

Finally, as shown in fig. 13 and 14, a dicing step is performed to obtain an individual fan-out LED package structure.

As shown in fig. 14, this embodiment further provides a package structure of a fan-out LED, where the package structure includes: a re-routing layer 40, the re-routing layer 40 including a first side and an opposing second side; an LED chip 21 located on the second surface of the redistribution layer 40, wherein a metal lead column 205 is disposed on an electrode 204 of the LED chip 21, the metal lead column is encapsulated by a first encapsulation layer 206, and the metal lead column 205 is exposed from the first encapsulation layer 206 and connected to the redistribution layer 40; the second packaging layer 103 wraps the side face of the LED chip 21, and a light emitting surface of the LED chip 21 is exposed out of the second packaging layer 103; and a metal bump 501 formed on a first surface of the redistribution layer 40 to electrically extract the LED chip 21 through the redistribution layer 40.

The material of the first encapsulation layer 206 includes one of polyimide, silicone, and epoxy. The material of the metal lead post 205 includes one of copper, gold, and silver.

The LED chip 21 includes an RGB three primary color LED chip 21. In this embodiment, the LED chip 21 includes an RGB three-primary-color LED chip 21, as shown in fig. 4, the RGB three-primary-color LED chip 21 includes a red light emitting unit 201, a green light emitting unit 202, and a blue light emitting unit 203, the RGB three-primary-color LED chip 21 has an electrode 204, the electrode 204 is electrically connected to the red light emitting unit 201, the green light emitting unit 202, and the blue light emitting unit 203, and the red light emitting unit 201, the green light emitting unit 202, and the blue light emitting unit 203 can emit light simultaneously or selectively by applying a suitable voltage to the electrode 204.

The LED chip 21 has a metal lead column 205 on an electrode 204, the metal lead column is encapsulated by a first encapsulation layer 206, and the metal lead column 205 is exposed from the first encapsulation layer 206 and connected to the redistribution layer 40. The LED chips 21 are fixed on the second surface of the redistribution layer 40 in an array, which may be a rectangular array, a triangular array, etc., and the arrangement may be selected according to the requirement of the light emitting lattice, which is not limited to the examples listed herein.

By way of example, the material of the second encapsulation layer 103 includes one of polyimide, silicone, and epoxy. The material of the second packaging layer 103 may be the same as or different from the first packaging layer 206, and may be selected according to actual requirements. The first metal bump 501 includes one of tin solder, silver solder, and gold-tin alloy solder.

The embodiment also provides an electronic display screen, which comprises the package structure of the fan-out type LED. Wherein the dot pitch of the electronic display screen is not more than 0.5 mm.

Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A package structure of a fan-out LED, the package structure comprising:

A rewiring layer including a first side and an opposing second side;

The LED chip is positioned on the second surface of the rewiring layer, a metal lead post is arranged on an electrode of the LED chip and is packaged by a first packaging layer, and the metal lead post is exposed out of the first packaging layer and is connected with the rewiring layer;

The second packaging layer wraps the side face of the LED chip, and the light-emitting surface of the LED chip is exposed out of the second packaging layer;

and the metal bump is formed on the first surface of the rewiring layer so as to realize the electrical leading-out of the LED chip through the rewiring layer.

2. The package structure of the fan-out LED of claim 1, wherein: the LED chip comprises an RGB three-primary-color LED chip.

3. The package structure of the fan-out LED of claim 1, wherein: the LED chips are arranged on the second surface of the rewiring layer in an array mode.

4. The package structure of the fan-out LED of claim 1, wherein: the metal lead post is made of one of copper, gold and silver.

5. The package structure of the fan-out LED of claim 1, wherein: the material of the second packaging layer comprises one of polyimide, silica gel and epoxy resin.

6. The package structure of the fan-out LED of claim 1, wherein: the metal bump comprises one of tin solder, silver solder and gold-tin alloy solder.

7. An electronic display screen, characterized in that the electronic display screen comprises the package structure of the fan-out LED as claimed in any one of claims 1 to 6.

8. The electronic display of claim 7, wherein: the dot pitch of the electronic display screen is not more than 0.5 mm.