KR-20260064500-A - VERTICALLY STACKED RED-GREEN-BLUE FULL-COLOR CHIP-ON-CARRIER FOR MICROLED DISPLAY PANELS AND METHOD OF MANUFACTURING THE SAME

KR20260064500AKR 20260064500 AKR20260064500 AKR 20260064500AKR-20260064500-A

Abstract

The present invention relates to a vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, comprising a temporary wafer; and a light-emitting part stacked vertically through a bonding layer, each comprising a plurality of LED stacks aligned on the temporary wafer, wherein each of the plurality of LED stacks has a short passage formed in a portion of the region so that current is passed to the light-emitting part where the short passage is not formed, thereby emitting only a specific color, and the short passage comprises a first short passage formed to correspond to the width of the light-emitting part and a second short passage formed to penetrate the light-emitting part. According to the present invention, a chip-on-carrier is formed in a state in which a plurality of LED stacks are vertically stacked with a plurality of light-emitting parts on a temporary wafer, and since a short passage is already formed in each of the plurality of LED stacks, a company receiving the chip-on-carrier can easily manufacture a microLED display panel by only a bonding process with a silicon (Si) CMOS or glass TFT backplane wafer without the need to perform a separate epitaxial growth or stacking process. Accordingly, the manufacturing process is simplified, the burden on manufacturing equipment and infrastructure is reduced, the process time is shortened, and the manufacturing yield is improved.

Inventors

송준오
문지형
김태경
윤형선

Assignees

웨이브로드 주식회사

Dates

Publication Date: 20260507
Application Date: 20250902
Priority Date: 20241030

Claims (10)

Temporary wafer; and Each includes a light-emitting part stacked vertically through a bonding layer, and includes a plurality of LED stacks aligned on the temporary wafer. Each of the plurality of the above LED stacks is, By forming a short passage in some areas, current is passed to the light-emitting part where the short passage is not formed, thereby emitting only a specific color, and The above short passage is, A vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, comprising a first short passage formed to correspond to the width of the light-emitting portion and a second short passage formed to penetrate the light-emitting portion.
In claim 1, A plurality of the above LED stacks, A vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, comprising a first LED stack including a first light-emitting part emitting a first color, a second LED stack including a second light-emitting part emitting a second color, and a third LED stack including a third light-emitting part emitting a third color.
In claim 2, The above-mentioned first LED laminate is, It includes the first short passage formed in the third light-emitting part, and the second short passage formed to penetrate the second light-emitting part. The above second LED laminate is, It includes the first short passage formed in the third light-emitting part and the first short passage formed in the first light-emitting part, The above third LED laminate is, A vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, comprising the second short passage formed to penetrate the second light-emitting part and the first short passage formed in the first light-emitting part portion.
In claim 1, On the upper or lower part of a plurality of the above-mentioned LED stacks, Vertical stacked red-green-blue full-color chip-on-carrier for microLED display panels, in which a common electrode is formed.
In claim 1, On the above temporary wafer, Vertical stacked red-green-blue full-color chip-on-carrier for microLED display panels, in which a sacrificial separation layer is formed.
A preparation step for preparing a plurality of front wafers including a support wafer and a light-emitting part; A stacking step of forming a stack in which a plurality of light-emitting parts are vertically stacked on a support wafer by repeatedly bonding another front wafer onto a front wafer through a bonding layer and then removing the support wafer of the other front wafer; A first processing step of forming a short passage on one surface of the above laminate; A second processing step of bonding a temporary wafer to one side of the laminate, removing the support wafer, and forming the shot passage on the other side of the laminate; and The method includes an etching step in which a plurality of LED stacks are aligned on a temporary wafer by etching the stack to separate them into preset units. Each of the plurality of the above LED stacks is, By forming a short passage in some areas, current is passed to the light-emitting part where the short passage is not formed, thereby emitting only a specific color, and The above short passage is, A vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, comprising a first short passage formed to correspond to the width of the light-emitting portion and a second short passage formed to penetrate the light-emitting portion.
In claim 6, A plurality of the above LED stacks, A method for manufacturing a vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, comprising a first LED stack including a first light-emitting part emitting a first color, a second LED stack including a second light-emitting part emitting a second color, and a third LED stack including a third light-emitting part emitting a third color.
In claim 7, The above-mentioned first LED laminate is, It includes the first short passage formed in the third light-emitting part, and the second short passage formed to penetrate the second light-emitting part. The above second LED laminate is, It includes the first short passage formed in the third light-emitting part and the first short passage formed in the first light-emitting part, The above third LED laminate is, A method for manufacturing a vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, comprising the second short passage formed to penetrate the second light-emitting part and the first short passage formed in the first light-emitting part portion.
In claim 6, On the upper or lower part of a plurality of the above-mentioned LED stacks, A method for manufacturing a vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel in which a common electrode is formed.
In claim 6, On the above temporary wafer, A method for manufacturing a vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel, wherein a sacrificial separation layer is formed.

Description

VERTICALLY STACKED RED-GREEN-BLUE FULL-COLOR CHIP-ON-CARRIER FOR MICROLED DISPLAY PANELS AND METHOD OF MANUFACTURING THE SAME The present invention relates to a vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel and a method for manufacturing the same. More specifically, it relates to a vertically stacked red-green-blue full-color chip-on-carrier for a microLED display panel and a method for manufacturing the same, which utilizes an engineering monolithic epitaxy wafer method and eliminates the need for a color filter by causing each LED stack to emit only a specific color. The types of implementation for the recently trending Metaverse are classified into four forms: VR (virtual reality), AR (augmented reality), MR (mixed reality), and XR (extended reality). Among these, the future Metaverse ecosystem is expected to develop around XR, a reality that integrates VR, AR, and MR. To effectively implement this, devices (such as smart glasses and head-mounted displays) containing microdisplays with a diagonal length of less than one inch as core components are required, along with software for next-generation computing platforms capable of providing innovative user experiences. In particular, the development of high-performance microdisplay panel technology is absolutely necessary to provide XR users with the greatest sense of immersion, visibility, and convenience while minimizing dizziness. As illustrated in FIG. 1, the conventional microdisplay panel (10) is a technology that combines a Si CMOS semiconductor wafer process with a high-resolution, high-brightness ultra-small display process. The conventional microdisplay panel (10) may have a structure in which a Si CMOS wafer (11) having a crystal plane of 4" or larger (100) equipped with a plurality of CMOS electrode pads (12), a microLED electrode pad (14), and a transparent wafer (13) having a plurality of microLED chips (15) are bonded through a conductive bond (16). Meanwhile, the types of microdisplay panels expected to be applied to XR devices include liquid crystal (LC) based LCoS (LC on Si), OLED (organic light-emitting diode) based OLEDoS (OLED on Si), and ultra-small microLED based LEDoS (LED on Si) having a pixel size of less than 5㎛. In the case of VR with a low pixel density display, development and mass production are centered on LCoS and OLEDoS. However, with the advancement of metaverse implementation technology, there is an increasing need for lightweight AR, MR, and XR devices equipped with high pixel density microdisplay panels. In response to this need, there is an urgent need to develop LEDoS technology (which adopts a microLED pixel light source composed of red, green, and blue subpixels of less than 5㎛), which is attracting attention as a theoretically ideal solution based on the superior properties of inorganic materials, but a microdisplay panel platform for this has not yet been established. When applied to XR devices, microLED-based LEDoS with pixel sizes of less than 5㎛ offers the advantages of excellent power-to-performance ratio and short response speed. Additionally, it has a long lifespan due to its inorganic composition and allows for efficient power usage, which helps mitigate heat and enables long battery life. In particular, since XR devices have a very short distance between the display and the eyes, even a slight delay in image conversion can easily cause discomfort such as dizziness. Therefore, LEDoS, which has a nanosecond response speed, is considered the most suitable for XR devices compared to LCoS and OLEDoS, which have microsecond response speeds. Furthermore, it is assessed that the biggest reason LEDoS is attracting attention in AR, MR, and XR devices, unlike VR, is due to its brightness and luminous efficiency. Given the nature of smart glasses that can be worn regardless of location, high brightness is an essential condition to ensure normal operation even in outdoor environments such as sunlight. Theoretically, microLEDs support brightness levels of tens to millions of nits, and since microLEDs are inorganic rather than organic, they also have the advantage of high luminous efficiency. However, despite the aforementioned advantages, the biggest reason why ultra-small microLED-based LEDoS with pixel sizes of less than 5㎛ has not established itself as a key component of XR devices is the difficulty of mass production. In other words, since LEDoS requires fixing millions of ultra-small microLEDs onto a Si CMOS wafer, the process difficulty is high and the yield is very low, leading to increased manufacturing costs and high component prices. This is reflected in the end consumer price, resulting in high-priced XR devices, making it difficult to meet market demand. Meanwhile, referring to Figure 2, until recently, the development of LEDoS with microLED light sources of group 3-5 compounds (GaN, GaP, etc.) has been carried out through traditional approaches such as ① monolithic