CN110783366A

CN110783366A - Full-color display chip and manufacturing process of semiconductor chip

Info

Publication number: CN110783366A
Application number: CN201911236461.8A
Authority: CN
Inventors: 朱涛
Original assignee: Suzhou Aoshi Micro Technology Co Ltd
Current assignee: Suzhou Aoshi Micro Technology Co Ltd
Priority date: 2019-12-05
Filing date: 2019-12-05
Publication date: 2020-02-11

Abstract

The invention discloses a full-color display chip and a manufacturing process of a semiconductor chip, which comprises the following steps: the array substrate comprises a substrate and a plurality of pairs of anode contact points and cathode contact points, wherein the substrate supports an array of pixel drivers, and a plurality of pairs of anode contact points and cathode contact points of the pixel drivers are arranged on the substrate; two or more layers stacked on top of said substrate and pixel driver, each layer containing a micro LED light emitting structure, each layer having a cathode electrode in communication with said anode contact and an anode electrode in communication with said cathode contact; the method is characterized in that: the LED light-emitting structures between adjacent layers are stacked up and down. The full-color display chip has the advantages of low pixel density and large light-emitting area, and the manufacturing process has the advantages of high interconnection density and low equipment investment.

Description

Full-color display chip and manufacturing process of semiconductor chip

Technical Field

The invention relates to the technical field of semiconductor component manufacturing, in particular to a full-color display chip; and also relates to a process for manufacturing a semiconductor chip capable of manufacturing the full-color display chip.

Background

The display portion (light emitting element) and the driving portion of the micro LED display are generally completed by a bonding process, and conventionally completed by a Flip-chip method, but in order to realize full color, three color (RGB) light emitting elements are required. Conventional bonding processes are only suitable for monochrome display manufacturing.

Chinese patent application publication No. CN110462850A discloses a micro LED display chip and a method for manufacturing a micro LED display chip, the display chip comprising a substrate, two or more layers with a flat interface between adjacent layers, each layer containing an array of micro LEDs.

In the structure, three single-color LEDs of red, green and blue which are arranged side by side in the horizontal direction form a pixel of the micro LED display screen, and the area of each single-color LED is smaller than 1/3 of the area of the pixel. The advantage of this arrangement is that the bonding process is relatively simple, and the chip assembly is completed by a single bond, but the disadvantages are: the pixel density increase of the process is limited by the limit of the single-layer process, that is, the resolution of the display screen can only reach one third of the limit of the single-layer process of the device.

Disclosure of Invention

In order to solve the above-mentioned technical problems, a first object of the present invention is to provide a full-color display chip capable of reducing the pixel density and increasing the light-emitting area under the condition of the same resolution; a second object of the present invention is to provide a manufacturing process of a semiconductor chip with less requirement for equipment.

In order to achieve the first object of the invention, the invention adopts the following technical scheme: a full-color display chip comprising:

the array substrate comprises a substrate and a plurality of pairs of anode contact points and cathode contact points, wherein the substrate supports an array of pixel drivers, and a plurality of pairs of anode contact points and cathode contact points of the pixel drivers are arranged on the substrate;

two or more layers stacked on top of said substrate and pixel driver, each layer containing a micro LED light emitting structure, each layer having a cathode electrode in communication with said anode contact and an anode electrode in communication with said cathode contact;

the LED light-emitting structures between adjacent layers are stacked up and down.

In the above technical solution, preferably, each of the layers includes a light-transmitting insulating layer located on the light-emitting side of the LED light-emitting structure.

In the above technical solution, preferably, a lens is further disposed on the insulating layer at the outermost layer.

In the above technical solution, it is preferable that projections of the LED light emitting structures of the respective vertically stacked layers on a plane on which the substrate is located partially overlap, and projections of the cathode electrodes and the anode electrodes of the LED light emitting structures of the respective layers on the plane on which the substrate is located are staggered from each other.

In the above technical solution, preferably, the LED light emitting structures of different layers generate light with different wavelengths.

In the above technical solution, preferably, the full-color display chip includes three layers, and the LED light emitting structures of the three layers are configured to provide red light, green light, and blue light, respectively.

In the above technical solution, preferably, the full-color display chip includes two layers, and the two layers are respectively configured to provide red light and green light, or the two layers are respectively configured to provide red light and blue light.

In the above technical solution, preferably, the LED light emitting structure is one of a III-V nitride epitaxial structure, a III-V arsenide epitaxial structure, a III-V phosphide epitaxial structure, and a III-V antimonide epitaxial structure.

In the above technical solution, preferably, each of the layers further includes a filling material, and the filling material is one or more selected from silicon oxide, aluminum oxide, silicon nitride, and organic transparent adhesive.

In order to achieve the second object of the invention, the invention adopts the following technical scheme: a process for manufacturing a semiconductor chip, comprising the steps of:

s0, providing a substrate for supporting the pixel driver array, wherein the substrate is provided with a first bonding surface and a plurality of pairs of anode contact points and cathode contact points which are exposed on the first bonding surface and electrically connected with the pixel driver array;

s1, providing a plurality of stacked layers, wherein each stacked layer comprises a substrate, an LED light-emitting structure formed on the substrate, and a cathode electrode and an anode electrode which are connected with the LED light-emitting structure;

s2, bonding a bottom layer, namely inversely bonding the stacked layer at the bottom layer on the substrate to ensure that an anode electrode and a cathode electrode of the LED light-emitting structure are respectively in conductive connection with a pair of anode contact points and a pair of cathode contact points on the substrate;

s3, punching holes in the bonded stacked layers to form holes penetrating through the stacked layers, and filling metal into the holes to form a plurality of electrode metal conductors;

s4, flip-chip bonding another stacked layer on the bottom stacked layer, so that the LED light emitting structure on the another stacked layer is stacked directly above the LED light emitting structure on the bottom stacked layer, and connecting the anode electrode and the cathode electrode of the LED light emitting structure on the another stacked layer with a plurality of the electrode metal conductors, respectively, filling and planarizing the another stacked layer;

and repeating the steps S3 and S4 until all the stacked layer bonding is completed.

In the above technical solution, preferably, the stacked layer is formed by:

s11, forming an LED epitaxial layer on a substrate;

s12, etching to form an island-shaped platform, and reserving an anode lead-out point and a cathode lead-out point at the outer edge of the island-shaped platform;

s13, respectively manufacturing metal electrodes on the anode leading-out point and the cathode leading-out point;

s14, filling a layer of filling material;

and S15, grinding the surface to be flat, so that the anode leading-out point and the cathode leading-out point are exposed to form a second bonding surface.

In the above technical solution, preferably, after each bonding, the substrate on the stacked layer is removed, and a light-transmitting insulating layer is formed on the surface of the substrate.

In the above technical solution, preferably, after bonding all the stacked layers, an optical lens is formed on the surface of the stacked layer of the surface layer.

In the above technical solution, preferably, a plurality of the stacked LED light emitting structures respectively generate light with different wavelengths.

In the above technical solution, preferably, the method bonds three stacked layers, and the three stacked layers have a red LED light emitting structure, a green LED light emitting structure, and a blue LED light emitting structure in sequence from the bottom layer to the top.

In the foregoing technical solution, preferably, the plurality of pairs of anode contacts and cathode contacts on the substrate are circumferentially disposed outside each of the LED light emitting structures. .

According to the full-color display chip, the LED light-emitting structures between the adjacent layers are stacked up and down, so that compared with the existing horizontal parallel arrangement mode, the pixel density can be reduced, the light-emitting area is increased, and the full-color display chip is suitable for the application of AR/VR and other full-color screen display devices; the improvement on the production process is correspondingly brought by the structural improvement, and compared with the existing production process that the display chip is bonded firstly and then etched, the manufacturing process of the semiconductor chip is suitable for industrially manufacturing the full-color display chip by etching firstly and then bonding.

Drawings

FIGS. 1-18 b are schematic flow charts illustrating a process for fabricating a semiconductor chip according to the present invention;

wherein: 100R, stacked layers (red); 100B, stacked layers (blue light); 100G, stack (green); 11. a P-type semiconductor; 12. a light emitting layer; 13. an N-type semiconductor; 10. an LED light emitting structure; 14b, an anode leading-out point; 14A, a cathode electrode; 14B, an anode electrode; 15. a filler material; 16. a second bonding surface; 17. a light-transmitting insulating layer; 170. a lens; 18. a metal filler; 18C, 18D, 18E and 18F are metal electrodes; 19. a substrate; 200. a pixel driver; 20. a substrate; 22. a first bonding surface; A. b, C, D, E, F are anode/cathode contact points.

Detailed Description

For the purpose of illustrating the technical content, the constructional features, the achieved objects and the effects of the invention in detail, reference will be made to the following detailed description of the embodiments in conjunction with the accompanying drawings. In this specification, the "bottom layer" corresponds to the lower side in fig. 18a, the "top layer" corresponds to the upper side in fig. 18a, the "outer side" corresponds to the outer side in fig. 18b, and the center in fig. 18b corresponds to the "inner side".

The invention mainly discloses a full-color Micro-LED chip which can be used for display screens of electronic equipment such as AR, VR and the like, but the invention is not limited to the specific application mentioned in the embodiment.

Fig. 18a is a cross-sectional view of a full-color display chip of the present invention in an exemplary embodiment, and fig. 18b is a top view of the full-color display chip, which has a 3-layer structure. In another exemplary application of the present invention, the chip may also be implemented by a 2-layer stack structure.

As can be seen from fig. 18b, the full-color display chip includes:

a substrate 20 for supporting the pixel driver 200, wherein the substrate 20 can be a silicon-based substrate, a sapphire substrate, a glass substrate, etc., the pixel driver can drive the LED light-emitting structure 10 array to emit light according to a set rule, thereby displaying a display image, the pixel driver has a plurality of pairs of anode contacts and cathode contacts for connecting with the LED light-emitting structure array, the full-color display chip shown in fig. 18a has 3 layers of LED light-emitting structures, 3 anode contacts and 3 cathode contacts are arranged on the corresponding substrate, wherein a-B are connected with two electrodes of the bottom layer of LED light-emitting structure, C-D are connected with two electrodes of the second layer of LED light-emitting structure, and E-F are connected with two electrodes of the surface layer of LED light-emitting structure. The surface layer of the substrate has a first bonding surface 22, the first bonding surface is made of a metal material, and the metal material is selected from one of Cu, Al, Au and the like;

3

stacked layers

100R, 100G, 100B stacked on top of the substrate 20 and the pixel driver 200, each stacked layer including a micro LED light emitting structure 10, each LED light emitting structure 10 having an anode electrode in conduction with the anode contact and a cathode electrode in conduction with the cathode contact; and the LED light-emitting structures 10 between adjacent layers are vertically stacked up and down, the structures of all the stacked layers are the same, the stacked layers are welded layer by layer through flip-chip welding, and the light-emitting side of the LED light-emitting structure 10 on the uppermost stacked layer is provided with a lens.

Because the LED light-emitting structure is transparent, the light-emitting of the LED is not influenced when a plurality of LED light-emitting structures are vertically stacked, and the area of each monochromatic pixel can be the same as that of the pixel unit when the LED light-emitting structures are vertically stacked, so that the pixel area can be maximized, and the pixel area of a full-color display chip is equal to the light-emitting area of the monochromatic LED light-emitting structure. Correspondingly, the structure of the full-color display chip has lower requirements on manufacturing equipment, can reduce the process difficulty of single-layer etching, simultaneously reduces the edge leakage effect of small pixels, and improves the luminous efficiency of an LED. If the full-color display chip is processed by the same equipment, the full-color display chip can obtain higher resolution.

Wherein, each stacked layer comprises a light-transmitting insulating layer 17 positioned at the light-emitting side of the LED light-emitting structure, and the material of the insulating layer is selected from one of silicon oxide, aluminum oxide, silicon nitride, organic transparent adhesive (such as Benzocyclobutene), and the like. Each of the stacked layers further includes a filling material, and the filling material is a material which is neither conductive nor transparent, such as a simple compound material of silicon dioxide, silicon nitride, or the like, or a material made by mixing a plurality of compounds.

The LED light-emitting structure can be any one of a III-V nitride epitaxial structure, a III-V arsenide epitaxial structure, a III-V phosphide epitaxial structure and a III-V antimonide epitaxial structure. Accordingly, the LED light emitting structures in the plurality of stacked layers respectively emit visible light with different wavelengths, and in the embodiment shown in fig. 18a, the plurality of LED light emitting structures respectively provide red light, green light, and blue light, which are sequentially arranged in the order of red, green, and blue from top to bottom. In other embodiments, the full-color display chip may alternatively have two stacked layers, with 2 LED light emitting structures providing red and green light, or red and blue light, respectively.

As shown in fig. 18b, projections of the LED light emitting structures in the plurality of stacked layers on the plane where the pixel driver is located partially overlap, the LED light emitting structures may be in a circular shape, a trapezoidal shape, or other regular or irregular shapes, and a plurality of pairs of anode contact points and cathode contact points on the substrate, and anode electrodes and cathode electrodes of the LED light emitting structures are respectively distributed on the periphery of the overlapping portion, so that projections of the cathode electrodes and the anode electrodes of the LED light emitting structures in the respective stacked layers on the plane where the pixel driver is located are mutually staggered. The cross-section of the LED light emitting structure may be of any shape, and is not necessarily limited to the circular shape in the present embodiment.

Fig. 1 to 18b are flow charts showing the manufacturing process of the full-color display chip. The process comprises the following steps of,

s0, manufacturing of the substrate: fabricating a pixel driver array 200 on a silicon-based substrate 20, which has a first bonding surface 22 and 3 pairs of anode and cathode contact points A, B, C, D, E, F exposed on the first bonding surface 22 and electrically connected to the pixel driver array, for example, a red, green and blue three-primary-color display chip in this embodiment, see fig. 6b where the pairs of anode and cathode contact points are distributed along the circumference;

s1, manufacturing of stacked layer 100:

s11, forming a GaN-LED epitaxial layer on the sapphire substrate 19, wherein the LED epitaxial layer includes an N-type semiconductor layer 13, a light emitting layer 12, and a P-type semiconductor layer 11, as shown in fig. 1;

s12, etching to form an island-shaped platform, and reserving an anode lead-out point 14B and a cathode lead-out point at the outer edge of the island-shaped platform, wherein in fig. 2a and 2B, the point 14B is the anode lead-out point, fig. 2B is a schematic top view of the stacked layers and is only used for showing the cross-sectional position, and fig. 2a is a cross-sectional view of a broken line along the point B in fig. 2B;

s13, forming metal electrodes on the anode lead-out point 14B and the cathode lead-out point respectively to form an anode electrode 14B and a cathode electrode 14A, as shown in fig. 3;

s14, filling a layer of filling material 15, as shown in FIG. 4A, FIG. 4A is a cross-sectional view taken along line 14A-14B in FIG. 4B;

s15, polishing the semiconductor surface by CMP to expose the anode electrode 14B and the cathode electrode 14A, thereby forming a second bonding surface 16, as shown in fig. 5.

The stack layer 100R of the LED light emitting structure with red light, the stack layer 100G of the LED light emitting structure with green light, and the stack layer 100B of the LED light emitting structure with blue light are respectively fabricated according to the above-described method for standby.

S2, bonding:

s21, flip-chip bonding the bottom stacked layer 100B on the substrate, and soldering the first bonding surface 22 and the second bonding surface 16 together, so that the anode electrode 14B and the cathode electrode 14A of the bottom LED light-emitting structure are electrically connected to the anode contact B and the cathode contact a on the substrate, respectively, as shown in fig. 6a and 6B, to form the semiconductor structure shown in fig. 7;

s22, laser lift-off sapphire substrate 19 on stack 100B, see fig. 8;

s23, dry etching, removing a portion of the GaN material, and recessing a portion of the epitaxial layer relative to the filling material 15 to form the structure shown in fig. 9;

s24, forming a transparent insulating layer 17 on the surface, as shown in fig. 10a and 10 b;

s3, punching:

s31, punching holes on the bottom layer stack layer by TSV process to form holes penetrating the bottom layer stack layer to all the other anode contacts and cathode contacts, where fig. 11a and 11b respectively show a cross-sectional structure along C-D, and the cross-section taken along the line E-F in fig. 11b is the same as the cross-sectional structure in fig. 11 a;

s32, filling the hole with metal filler 18, see fig. 12;

s34, performing surface smoothing by CMP process to expose the light-transmitting insulating layer 17 and the

metal electrodes

18C and 18D, as shown in fig. 13a and 13 b;

s4, repeated bonding:

s41, flip-chip bonding the green light stack layer 100G on the blue light stack layer 100B, so that the anode electrode and the cathode electrode of the LED light-emitting structure 10 on the green light stack layer 100G are respectively connected to the

metal electrodes

18C and 18D penetrating through the blue light stack layer 100B, and respectively form conductive connections with the anode/cathode contacts C and D on the substrate, as shown in fig. 14a and 14B;

repeating the above steps S31-S34, punching holes on the green light stack layer 100G to form through holes E, F penetrating through the green light stack layer 100G, see fig. 15a, 15 b; filling metal electrode material at the punched holes, as shown in fig. 16a and 16 b;

repeating step S41, flip-chip bonding the red light stack 100R on the green light stack 100G, so that the

electrodes

18E and 18F of the LED light emitting structure on the red light stack 100R are conductively connected with the electrode contacts E and F on the substrate, respectively, see fig. 17a and 17 b.

Finally, after the red light stack layer 100R is bonded, an optical lens 170 protruding from the surface insulating layer is formed on the surface of the red light stack layer 100R, see fig. 18a and 18 b.

The invention can provide a manufacturing process of a full-color micro-display chip, has good color display effect, and can realize the effects of reducing the pixel density and improving the light-emitting area by a multi-time bonding method.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A full-color display chip comprising:

two or more layers stacked on top of said substrate and pixel driver, each layer containing a micro LED light emitting structure, each layer having a cathode electrode in communication with said anode contact and an anode electrode in communication with said cathode contact; the method is characterized in that:

2. A full-color display chip according to claim 1, wherein: each layer comprises a light-transmitting insulating layer positioned on the light-emitting side of the LED light-emitting structure.

3. A full-color display chip according to claim 2, wherein: and a lens is also arranged on the insulating layer on the outermost layer.

4. A full-color display chip according to claim 1, wherein: the projections of the LED light-emitting structures of the layers stacked up and down on the plane of the substrate are partially overlapped, and the projections of the cathode electrodes and the anode electrodes of the LED light-emitting structures of the layers on the plane of the substrate are mutually staggered.

5. A full-color display chip according to claim 1, wherein: wherein the LED light emitting structures of different layers generate light with different wavelengths.

6. The full-color display chip according to claim 5, wherein: the full-color display chip comprises three layers, and the LED light-emitting structures of the three layers are respectively configured to provide red light, green light and blue light.

7. The full-color display chip according to claim 5, wherein: the full-color display chip comprises two layers, wherein the two layers are respectively configured to provide red light and green light, or the two layers are respectively configured to provide red light and blue light.

8. A full-color display chip according to claim 1, wherein: the LED light-emitting structure is one of a III-V nitride epitaxial structure, a III-V arsenide epitaxial structure, a III-V phosphide epitaxial structure and a III-V antimonide epitaxial structure.

9. A full-color display chip according to claim 1, wherein: each layer also comprises a filling material, and the filling material is selected from one or more of silicon oxide, aluminum oxide, silicon nitride and organic transparent adhesive.

10. A manufacturing process of a semiconductor chip is characterized by comprising the following steps:

11. The manufacturing process of a semiconductor chip according to claim 10, wherein: the stack of layers is formed by the steps of,

s11, forming an LED epitaxial layer on a substrate;

s14, filling a layer of filling material;

12. A process for manufacturing a semiconductor chip according to claim 11, wherein: and after each bonding is finished, removing the substrate on the stacked layer, and forming a light-transmitting insulating layer on the surface of the substrate.

13. The manufacturing process of a semiconductor chip according to claim 10, wherein: and forming an optical lens on the surface of the stacked layers of the surface layer after bonding of all the stacked layers is completed.

14. The manufacturing process of a semiconductor chip according to claim 10, wherein: the LED light emitting structures of a plurality of stacked layers respectively generate light with different wavelengths.

15. The manufacturing process of a semiconductor chip according to claim 10, wherein: and the three stacked layers are bonded together, and the blue light LED light-emitting structure, the green light LED light-emitting structure and the red light LED light-emitting structure are sequentially arranged on the three stacked layers from the bottom layer to the top.

16. The manufacturing process of a semiconductor chip according to claim 10, wherein: and a plurality of pairs of anode contact points and cathode contact points on the substrate are arranged on the outer side of each LED light-emitting structure along the circumferential direction.