CN115483241A - Micro display device and manufacturing method thereof - Google Patents
Micro display device and manufacturing method thereof Download PDFInfo
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- CN115483241A CN115483241A CN202110602090.1A CN202110602090A CN115483241A CN 115483241 A CN115483241 A CN 115483241A CN 202110602090 A CN202110602090 A CN 202110602090A CN 115483241 A CN115483241 A CN 115483241A
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- 239000002184 metal Substances 0.000 claims abstract description 70
- 239000000463 material Substances 0.000 claims abstract description 5
- 239000000758 substrate Substances 0.000 claims description 58
- 238000005530 etching Methods 0.000 claims description 9
- 238000004806 packaging method and process Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 12
- 230000010354 integration Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 230000003190 augmentative effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000008447 perception Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 210000001525 retina Anatomy 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/15—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission
- H01L27/153—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission in a repetitive configuration, e.g. LED bars
- H01L27/156—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission in a repetitive configuration, e.g. LED bars two-dimensional arrays
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0033—Processes relating to semiconductor body packages
- H01L2933/0066—Processes relating to semiconductor body packages relating to arrangements for conducting electric current to or from the semiconductor body
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Abstract
The invention relates to a micro-display device and a manufacturing method thereof.A bonding metal pad is pre-buried on one of a light-emitting chip or a driving chip, the bonding metal pad is connected with a bonding surface through a metal lead, and after the light-emitting chip is bonded with the driving chip, the material on the back surface of the bonding metal pad is removed to expose the bonding metal pad outside the chip to form the bonding pad. Through the combination process, the integration level of the driving chip can be improved, the area of the chip is reduced, the yield is improved, and the cost is reduced.
Description
Technical Field
The invention belongs to the technical field of micro-display, and particularly relates to a micro-display device and a manufacturing method thereof.
Background
With the rapid development of the VR/AR (virtual reality/augmented reality) industry, there has been a high growth in the number of displays suitable for VR/AR. Since VR/AR systems are currently implemented in head-mounted devices, the display suitable for these devices must be a micro-display chip, typically with a diagonal dimension of up to 1 inch, most often 0.6-0.7 inches. Display devices in the field of current microdisplays are often used to produce high-brightness microdisplay images, which are projected through an optical system for perception by an observer, and the projection target may be the retina (virtual image) or a projection screen (real phase). The conventional micro display screen is not used for direct visual observation, and has a small Pixel size and a high Pixel density Pixel Per Inch (PPI). The traditional Micro display technology comprises LCoS (Liquid Crystal on Silicon) and DLP (Digital Light Processing), and the emerging technology is mainly Micro-LED, and the principle is that an LED epitaxial wafer is etched into independent pixels (the process and the product are called MESA) in a high-precision pattern exposure, development and etching mode, and the size of the pixels is usually in the micrometer scale (0.1-50 mu m).
The micro display chip is formed by bonding an LED light-emitting chip and a driving chip, but after the LED light-emitting chip and the driving chip are bonded, the LED light-emitting chip and the driving chip are electrically interconnected with an external circuit. A larger chip area is often required to be reserved in a general electrical interconnection manner, and the bonding pad is designed in a region where the driving chip exceeds the light emitting chip and is also a non-light-emitting region of the micro display device, as shown in fig. 1 and 2. This leads to the reduction of the integration level of the chip, and is limited by the subsequent bonding process capability, the precision requirements on the bonding pad and the light-emitting chip are high, the process difficulty is high, and further the cutting rate of the driving chip on the wafer is reduced, which leads to the reduction of the yield of the chip, and the increase of the cost of a single chip.
Disclosure of Invention
In order to solve the above-mentioned problems, an object of the present invention is to provide a micro display device with a smaller chip area, higher integration, and lower cost, and a method for manufacturing the same.
In order to achieve the purpose of the invention, the invention adopts the following technical scheme: a micro display device comprises a first chip and a second chip which are mutually bonded, wherein one of the first chip and the second chip is a light emitting chip, the other chip is a driving chip, the light emitting chip is provided with a plurality of LED light emitting units, the driving chip comprises a substrate and a driving circuit which provides driving signals for the LED light emitting units, a plurality of bonding metal pads are pre-embedded on the first chip, a bonding surface of the second chip is provided with a plurality of metal electrodes, one side of each bonding metal pad is electrically interconnected with the plurality of metal electrodes through metal outgoing lines, and the other side of each bonding metal pad is exposed on the surface of the first chip to form a plurality of bonding pads.
In an embodiment of the present application, the first chip is a light emitting chip, and the second chip is a driving chip.
In an embodiment of the present application, the light emitting chip has a display area and a non-display area, the non-display area is distributed at the periphery of the display area, and the plurality of bonding pads are distributed in the non-display area of the light emitting chip.
In an embodiment of the present application, the bonding pad is located on a light emitting surface side of the light emitting chip.
In one embodiment of the present application, the first chip and the second chip have the same area and shape, so that the first chip covers all metal electrodes on the second chip.
In an embodiment of the present application, the first chip and the second chip may have different area sizes and shapes, respectively.
In an embodiment of the present application, to further increase the light emitting area, the area of the light emitting chip is larger than the area of the driving chip.
Another embodiment of the present invention provides a method for manufacturing the above-mentioned micro-display device, comprising: a method of fabricating a micro-display device, comprising the steps of:
s1, providing a first substrate, wherein the first substrate is provided with a first substrate and a first device layer formed on the front surface of the first substrate;
s2, etching a deep pit on the first device layer;
s3, embedding a bonding metal pad in the deep pit;
s4, forming an insulating dielectric layer, etching the insulating dielectric layer to form a groove communicated with the bonding metal pad, filling metal in the groove, and forming a metal outgoing line connected with the front surface of the bonding metal pad;
s5, providing a second substrate, wherein the second substrate is provided with a second substrate, a second device layer and a plurality of metal electrodes, and the second device layer is formed on the second substrate;
s6, bonding the first substrate and the second substrate to enable the plurality of metal electrodes to be electrically interconnected with the metal outgoing lines respectively;
s7, removing the first substrate;
s8, removing partial materials on the back surface of the first substrate to expose the back surface of the bonding metal pad to form a bonding pad;
the LED light-emitting device comprises a first device layer, a second device layer, a plurality of LED light-emitting units and a driving circuit, wherein the plurality of LED light-emitting units are processed on one of the first device layer and the second device layer in advance, and the driving circuit is processed on the other one of the first device layer and the second device layer in advance.
In an embodiment of the present application, one of Die-Die bonding, die-Wafer bonding, and Wafer-Wafer bonding is adopted in the step S6.
In an embodiment of the present application, the first substrate is a light emitting chip, the second substrate is a driving chip, and the package pins are formed in a non-display area of the light emitting chip.
In one embodiment of the present application, the first substrate and the second substrate have the same area and shape.
Compared with the prior art, the invention has the following beneficial effects: the bonding pad metal is pre-buried on the light-emitting chip or the driving chip, and then the bonding pad on the light-emitting chip is interconnected with the driving chip through a chip bonding process, so that the effects of improving the integration level of the driving chip, reducing the chip area, improving the yield and reducing the cost are achieved.
Drawings
FIG. 1 is a wafer carrying a plurality of micro-display devices;
FIG. 2 is a top view of a microdisplay device before modification;
FIG. 3 is a side view of a microdisplay device before modification;
FIG. 4 is a top view of a microdisplay device of the present application;
FIG. 5 is a side view of a microdisplay device of the present application;
FIGS. 6-10 are schematic views illustrating the manufacturing process of the micro-display device of the present application;
wherein: 100. a micro display device; 101. a light emitting chip; 102. a driver chip;
10. a first chip; 11. a first substrate; 12. a first device layer; 121. a first layer; 122. a second layer; 13. deep pit; 14. a bond metal pad; 15. a metal lead-out wire; 16. an insulating dielectric layer; 17. a dielectric layer; 20. a second chip; 21. a second substrate; 22. a second device layer; 23. a metal electrode; 30. and a bonding pad.
Detailed Description
For the purpose of explaining the technical content, the structural features, the achieved objects and the effects of the invention in detail, the following description is made in conjunction with the embodiments and the accompanying drawings, wherein the "up" and "down" positional relationships in the present specification correspond to the up and down directions in fig. 6, respectively.
The present application discloses a micro display device 100 including a first chip 10 and a second chip 20 bonded to each other. The method is applied to wearable devices such as AR, VR, HUD and watch, or electronic devices such as a display screen. One of the first chip 10 and the second chip 20 is a light emitting chip, and the other is a driving chip. The light emitting chip can be one of semiconductor light emitting devices such as Micro-LED, mini-LED or OLED. The driving chip can be a COMS, TFT or other driving circuits.
The bonding metal pad is pre-buried on one of a light-emitting chip or a driving chip, the bonding metal pad is connected with a bonding surface through a metal lead, and after the light-emitting chip and the driving chip are bonded, material on the back surface of the bonding metal pad is removed to be exposed outside the chip to form the bonding pad.
The present application will be described in detail below, taking the formation of bond pads on a light emitting chip as an example.
Referring to fig. 10, a micro display device 100 of the present application includes a first chip 10 and a second chip 20 bonded to each other. The first chip 10 is a Micro-LED light emitting chip, and the second chip 20 is a driving chip. The light emitting chip is provided with a plurality of LED light emitting units (not shown in the figure), and the driving chip includes a substrate and a driving circuit for providing driving signals for the LED light emitting units. According to the spirit of the present application, it is understood that the first chip may be a driving chip and the second chip may be a light emitting chip as a variation of the present application.
The first chip 10 has a first device layer 12, a plurality of bonding metal pads 14 are embedded in the first device layer 12, the front surfaces of the bonding metal pads 14 are connected to the bonding surface of the first chip 10 through metal outgoing lines 15, and the back surfaces of the bonding metal pads 14 are exposed or partially exposed on the surface of the first chip to form a plurality of bonding pads 30 for connecting with an external circuit.
The second chip 20 has a second substrate 21 and a second device layer 22 formed on the second substrate 21, the second device layer 22 has a plurality of metal electrodes 23 electrically connected to the driving circuit, and the metal electrodes 23 form pads on the bonding surface of the second chip, which are electrically connected to the metal lead-out wires 15 on the first chip 10.
For a light emitting chip, it has a display area and a non-display area. Referring to fig. 4 and 5, in the present embodiment, the first chip 10 is a light emitting chip, and the second chip 20 is a driving chip. The bonding pads 30 are distributed in the non-display area of the light emitting chip, and the non-display area is distributed at the periphery of the display area. In particular, a plurality of bonding pads 30 are arranged in two rows on both sides of the display area.
In one embodiment, the bonding pad 30 is disposed on a light emitting surface side of the light emitting chip. In other embodiments, the bonding pad 30 may also be located on a side of the light emitting chip other than the light emitting surface.
In the preferred embodiment of the present application, the first chip 10 has the same area and shape as the second chip 20, i.e. the first chip 10 can cover all the metal electrodes on the second chip 20. The structure has the advantages that the light-emitting area of the first chip can be enlarged, the integration level of the driving chip is improved, the area of the chip can be reduced by 5 percent in prediction, the yield is improved by 6-7 percent, and the overall cost is reduced by about 10 percent.
In other embodiments of the present application, the first chip 10 and the second chip 20 may have different areas or different shapes, as long as the bonding pads of the two chips are in one-to-one correspondence, and finally, the electrical connection can be formed. In order to obtain a larger display area, the area of the light emitting chip can be increased to be larger than that of the driving chip, so that a more display effect is obtained.
The present application further discloses a method for manufacturing the above-mentioned micro-display device, which comprises the following steps:
s1, as shown in fig. 6, providing a first substrate, where the first substrate has a first substrate 11 and a first device layer 12 formed on a front surface of the first substrate 11, and the first device layer 12 includes a first layer 121 and a second layer 122;
s2, etching a deep pit 13 on the first device layer 12;
s3, embedding bonding pad metal in the deep pit 13 to form a bonding metal pad 14, wherein the area of the bonding metal pad 14 is smaller than that of the bottom of the deep pit 13, namely, a gap is reserved between the bonding metal pad 14 and the edge of the deep pit 13;
s4, referring to fig. 8, carrying out planarization treatment on the first substrate, forming an insulating dielectric layer 16 on the first device layer 12, etching the insulating dielectric layer 16 to form a groove communicated with the bonding pad metal, filling metal in the groove to form a metal outgoing line 15 connected with the front surface of the bonding metal pad 14, wherein the bonding metal pad 14 and the metal outgoing line 15 are wrapped by the insulating dielectric layer 16 and insulated from other devices of the first device layer 12;
s5, providing a second base plate, wherein the second base plate is provided with a second substrate 21, a second device layer 22 formed on the second substrate 21 and a plurality of metal electrodes 23;
s6, bonding the first substrate and the second substrate to enable a plurality of metal electrodes 23 on the second substrate to be electrically connected with the metal outgoing lines 15 on the first substrate respectively, and referring to fig. 9;
s7, removing the first substrate 11, and forming a protective medium layer 17 on the back of the first substrate 11;
and S8, removing partial materials on the back surface of the first substrate to expose the back surface of the bonding metal pad 14, so as to form a packaging bonding pad 30, as shown in FIG. 10.
As described above, in the embodiment of the present application, the bonding metal pad may be pre-embedded on the light emitting chip, and may also be pre-embedded on the driving chip. In the specific scheme provided in this embodiment, the first device layer 12 has a plurality of LED light emitting units, and the second device layer 22 has a driving circuit processed thereon. The first substrate is a light emitting chip, the second substrate is a driving chip, and the bonding pad 30 is formed in a non-display region of the light emitting chip.
In one embodiment, step S3 further includes film formation, photolithography, and etching processes, so as to finally pre-embed the bonding pad metal in the deep pit 13.
In a preferred embodiment, the area and the shape of the light emitting chip and the driving chip are completely the same, and the light emitting chip and the driving chip can form an attractive and neat appearance after being combined. In other embodiments, to further increase the light emitting area, it is also conceivable to make the light emitting chip slightly larger than the driving chip.
In the step S6, the bonding between the first substrate and the second substrate may be any one of Die-Die bonding, die-Wafer bonding, or Wafer-Wafer bonding. Wherein Die-Die refers to chip-to-chip bonding, die-Wafer refers to chip-to-Wafer bonding, and Wafer-to-Wafer refers to Wafer-to-Wafer bonding.
In step S8, the back surface of the first substrate is exposed by back surface thinning, polishing, photolithography, and etching processes.
After the bonding pad 30 is formed, the micro display device and the outside can be electrically connected through the bonding pad 30 by a Wire Bond or Flip Chip bonding process.
The integration level of the driving chip can be improved by measuring and calculating, the area of the chip can be reduced by about 5 percent, the yield can be improved by 6 to 7 percent, and the overall cost can be reduced by about 10 percent.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the foregoing description only for the purpose of illustrating the principles of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims, specification, and equivalents thereof.
Claims (10)
1. A micro display device comprises a first chip and a second chip which are mutually bonded, wherein one of the first chip and the second chip is a light emitting chip, the other chip is a driving chip, a plurality of LED light emitting units are arranged on the light emitting chip, the driving chip comprises a substrate and a driving circuit for providing driving signals for the LED light emitting units, and the micro display device is characterized in that: the chip comprises a first chip, a second chip and a plurality of bonding metal pads, wherein the first chip is embedded with the plurality of bonding metal pads, the bonding surface of the second chip is provided with the plurality of metal electrodes, one side of each bonding metal pad is electrically interconnected with the plurality of metal electrodes through a metal outgoing line, and the other side of each bonding metal pad is exposed on the surface of the first chip to form the plurality of bonding pads.
2. A microdisplay device according to claim 1 wherein: the first chip is a light-emitting chip, and the second chip is a driving chip.
3. A microdisplay device as in claim 2 wherein: the light-emitting chip is provided with a display area and a non-display area, the non-display area is distributed on the periphery of the display area, and the bonding pads are distributed in the non-display area of the light-emitting chip.
4. A microdisplay device as in claim 2 wherein: the bonding pad is positioned on one side of the light-emitting surface of the light-emitting chip.
5. A microdisplay device as in claim 1 wherein: the first chip and the second chip have the same area and shape, so that the first chip covers all the metal electrodes on the second chip.
6. A microdisplay device as in claim 1 wherein: the area of the light-emitting chip is larger than that of the driving chip.
7. A method of manufacturing a microdisplay device comprising the steps of:
s1, providing a first substrate, wherein the first substrate is provided with a first substrate and a first device layer formed on the front surface of the first substrate;
s2, etching a deep pit on the first device layer;
s3, embedding a bonding metal pad in the deep pit;
s4, forming an insulating dielectric layer, etching the insulating dielectric layer to form a groove communicated with the bonding metal pad, filling metal in the groove, and forming a metal outgoing line connected with the front surface of the bonding metal pad;
s5, providing a second substrate, wherein the second substrate is provided with a second substrate, a second device layer and a plurality of metal electrodes, and the second device layer is formed on the second substrate;
s6, bonding the first substrate and the second substrate to enable the plurality of metal electrodes to be electrically interconnected with the metal outgoing lines respectively;
s7, removing the first substrate;
s8, removing partial materials on the back surface of the first substrate to expose the back surface of the bonding metal pad to form a bonding pad;
the LED light-emitting device comprises a first device layer, a second device layer, a plurality of LED light-emitting units and a driving circuit, wherein the plurality of LED light-emitting units are processed on one of the first device layer and the second device layer in advance, and the driving circuit is processed on the other one of the first device layer and the second device layer in advance.
8. The manufacturing method according to claim 7, characterized in that: in the step S6, one of Die-Die bonding, die-Wafer bonding or Wafer-Wafer bonding is adopted.
9. The manufacturing method according to claim 7, characterized in that: the first substrate is a light-emitting chip, the second substrate is a driving chip, and the packaging pins are formed in a non-display area of the light-emitting chip.
10. The manufacturing method according to claim 7, characterized in that: the first substrate and the second substrate have the same area and shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110602090.1A CN115483241A (en) | 2021-05-31 | 2021-05-31 | Micro display device and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110602090.1A CN115483241A (en) | 2021-05-31 | 2021-05-31 | Micro display device and manufacturing method thereof |
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| Publication Number | Publication Date |
|---|---|
| CN115483241A true CN115483241A (en) | 2022-12-16 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202110602090.1A Pending CN115483241A (en) | 2021-05-31 | 2021-05-31 | Micro display device and manufacturing method thereof |
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| CN (1) | CN115483241A (en) |
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- 2021-05-31 CN CN202110602090.1A patent/CN115483241A/en active Pending
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