KR20240147152A - Display device using light emitting device - Google Patents

Abstract

The present invention is applicable to a technical field related to a display device, and relates to, for example, a display device using a micro LED (Light Emitting Diode). The present invention may be configured to include: a wiring substrate; a unit metal pad defining a unit subpixel area and arranged on the wiring substrate to form a unit subpixel; a light emitting element in which a first type electrode positioned on a semiconductor layer is electrically connected to the unit metal pad by first conductive particles; and a first pressure receiving layer positioned between the wiring substrate and the unit metal pad and increasing a contact area between the metal pad and the first conductive particle by pressure applied by the first conductive particle.

Description

Display device using light-emitting element {DISPLAY DEVICE USING LIGHT EMITTING DEVICE}

The present invention is applicable to the technical field related to display devices, and relates to, for example, a display device using a micro LED (Light Emitting Diode).

Recently, display devices with excellent characteristics such as thinness and flexibility are being developed in the field of display technology. The major displays currently commercialized are represented by LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diodes).

Meanwhile, a light-emitting diode (LED) is a semiconductor light-emitting device that is well known for converting electric current into light. Starting with the commercialization of a red LED using GaAsP compound semiconductors in 1962, it has been used as a light source for display images in electronic devices, including information and communication devices, along with green LEDs of the GaP:N series.

Recently, these light-emitting diodes (LEDs) have been gradually miniaturized and manufactured into micrometer-sized LEDs, which are used as pixels in display devices.

LEDs, which are high-brightness elements, are being used not only for lighting but also as pixels in signage display devices. One example of a method for mounting LEDs on PCBs in display devices is using soldering.

The soldering method has the advantage of being easy to pattern through screen printing and having good environmental reliability for electrical bonding. On the other hand, it is difficult to print precisely using screen printing, and if the gap between the LED electrode pad and the electrode pad of the wiring board becomes narrow, the possibility of an electrical short circuit increases, so it is usually used when the minimum gap between the pads is 50 ㎛ or more.

Accordingly, an electrical connection method is being used by printing a liquid material containing conductive particles such as anistropic conductive paste (ACP). This method enables electrical connection without major problems even when the gap between pads is narrow.

In cases where the device has a size of 50 ㎛ or less, such as a micro LED, electrical contact due to randomness, such as with ACP, is difficult, and a method of fixing conductive particles, such as ICP (immovable conductive paste), to a certain area can be used.

When electrical connection is made using conductive particles, since the conductive particles have a structure in which they are fixed by polymer resin, peeling between the interfaces of different materials may occur due to shrinkage and expansion during the subsequent high-temperature process.

Therefore, when a heat treatment process is performed at a temperature of approximately 260 degrees after an electrical connection is made using conductive particles, a situation may occur in which the conductive particles are separated from the electrode pad.

Therefore, a solution to solve these problems is required.

The technical problem to be solved by the present invention is to provide a display device using a light-emitting element capable of improving reliability against high-temperature thermal shock, etc., after forming an electrical connection between the light-emitting element and the electrode pad using conductive particles.

Specifically, the present invention aims to provide a display device using a light-emitting element capable of forming a reliable and stable electrical connection without causing the conductive particles to become separated from the electrode pad even when a heat treatment process is performed after forming an electrical connection using conductive particles.

Furthermore, those skilled in the art will understand from the entire scope of the specification and drawings that according to other embodiments of the present invention, there may be additional technical problems not mentioned herein.

As a first viewpoint for achieving the above technical task, the present invention may be configured to include: a wiring board; a unit metal pad defining a unit subpixel area and arranged on the wiring board to form a unit subpixel; a light emitting element in which a first type electrode positioned on a semiconductor layer is electrically connected to the unit metal pad by first conductive particles; and a first pressure receiving layer positioned between the wiring board and the unit metal pad and increasing a contact area between the metal pad and the first conductive particle by pressure applied by the first conductive particle.

As an exemplary embodiment, the first pressure-bearing layer may have a modulus lower than at least one of the metal pad and the wiring substrate.

As an exemplary embodiment, the first pressure-bearing layer may include second conductive particles having a smaller size than the first conductive particles.

As an exemplary embodiment, the first pressure-bearing layer may have a protrusion shape positioned between the individual first conductive particles.

As an exemplary embodiment, a second pressure-receiving layer may be positioned between the semiconductor layer of the light-emitting element and the first type electrode.

As an exemplary embodiment, the second pressure-bearing layer may be covered by the first type electrode.

As an exemplary embodiment, the second pressure-bearing layer may include third conductive particles that are smaller in size than the first conductive particles.

As an exemplary embodiment, the second pressure-bearing layer may have a protrusion shape positioned between individual conductive particles.

As a second viewpoint for achieving the above technical task, the present invention comprises: a wiring board; unit metal pads arranged on the wiring board; and a unit package electrically connected to the unit metal pads by first conductive particles, wherein the unit package comprises: at least one electrode pad; a pressure-receiving layer positioned on the electrode pad; a device structure positioned on the pressure-receiving layer; and a through electrode penetrating the pressure-receiving layer and connected to the electrode pads and the device structure, wherein the pressure-receiving layer can increase a contact area between the electrode pads and the first conductive particles by pressure applied by the first conductive particles.

As an exemplary embodiment, the element structure may include a connection pad connected to the through-hole electrode; and a light-emitting element connected to the connection pad.

As an exemplary embodiment, the electrode of the light-emitting element may be connected to the connecting pad by a second conductive particle.

As an exemplary embodiment, the device structure may include an integrated circuit chip connected to the through-hole electrode.

As an exemplary embodiment, the pressure-receiving layer may have a Young's modulus lower than at least one of the electrode pad and the wiring substrate.

First, according to an embodiment of the present invention, by forming an electrical connection between a light-emitting element and an electrode pad using conductive particles, reliability against high-temperature thermal shock, etc. can be improved.

That is, a reliable and stable electrical connection can be secured between the light-emitting element and the electrode pad.

Specifically, even when a heat treatment process is performed at a temperature of approximately 260 degrees after an electrical connection is made using conductive particles, the conductive particles do not become separated from the electrode pad, and a reliable and stable electrical connection can be made.

Furthermore, according to another embodiment of the present invention, there are additional technical effects not mentioned herein. Those skilled in the art can understand this through the entire purpose of the specification and drawings.

FIG. 1 is a cross-sectional view showing a unit pixel of a display device using a light-emitting element according to the first embodiment of the present invention.
Figure 2 is an enlarged view of part A of Figure 1.
FIG. 3 is an enlarged view showing a unit subpixel of a display device using a light-emitting element according to one embodiment of the present invention.
FIG. 4 is an enlarged view showing a unit subpixel of a display device using a light-emitting element according to another embodiment of the present invention.
FIGS. 5 and 6 are cross-sectional views showing unit pixels of a display device using a light-emitting element according to the second embodiment of the present invention.
FIG. 7 and FIG. 8 are cross-sectional views showing unit pixels of a display device using a light-emitting element according to a third embodiment of the present invention.
Fig. 9 is a cross-sectional view showing a unit pixel of a display device using a light-emitting element according to the fourth embodiment of the present invention.
FIG. 10 is a photograph showing a unit pixel of a display device using a light-emitting element according to the first embodiment of the present invention.

Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing symbols, identical or similar components will be given the same reference numerals and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not have distinct meanings or roles in themselves. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and that the technical ideas disclosed in this specification should not be construed as being limited by the attached drawings.

Furthermore, although each drawing is described for convenience of explanation, it is also within the scope of the present invention for a person skilled in the art to implement another embodiment by combining at least two or more drawings.

Additionally, when an element such as a layer, region or substrate is referred to as existing "on" another element, it will be understood that this may be directly on the other element, or that there may be intermediate elements in between.

The display device described in this specification is a concept that includes all display devices that display information as a unit pixel or a set of unit pixels. Therefore, it can be applied not only to finished products but also to components. For example, a panel corresponding to a component of a digital TV also independently corresponds to a display device in this specification. Finished products can include mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation, slate PCs, tablet PCs, Ultra Books, digital TVs, desktop computers, etc.

However, those skilled in the art will readily recognize that the configuration according to the embodiments described herein may be applied to devices capable of displaying, even if they are new product types developed in the future.

In addition, the semiconductor light-emitting device mentioned in the specification is a concept that includes LED, micro LED, etc., and can be used interchangeably.

Fig. 1 is a cross-sectional view showing a unit pixel of a display device using a light-emitting element according to the first embodiment of the present invention. In addition, Fig. 2 is an enlarged view of part A of Fig. 1.

Referring to FIG. 1, a display device (10) is illustrated in which light-emitting elements (310, 320, 330) forming a unit pixel (300) are installed on a wiring board (100). For example, the light-emitting elements (310, 320, 330) forming a unit pixel (300) may include a first light-emitting element (310), a second light-emitting element (320), and a third light-emitting element (330). For example, the first light-emitting element (310) may be a red light-emitting element (310) that emits red light, the second light-emitting element (320) may be a green light-emitting element (320) that emits green light, and further, the third light-emitting element (330) may be a blue light-emitting element (330) that emits blue light. An insulating layer (400) for planarization may be positioned between these light-emitting elements.

The wiring board (100) may have a plurality of wiring electrodes (not shown) positioned on the board (110). Here, the wiring electrodes may include data electrodes (pixel electrodes) and scan electrodes (common electrodes). These wiring electrodes may be connected to metal pads (121, 122), respectively. Accordingly, the metal pads (121, 122) and the wiring electrodes (121, 122) may be described using the same drawing symbols.

As described above, three light-emitting elements (310, 320, 330) can form a unit pixel (300). Although FIG. 1 shows one unit pixel (300), such unit pixels (300) can be repeatedly provided on a wiring board (100). At this time, one light-emitting element can form a unit sub-pixel. FIG. 1 shows a state in which light-emitting elements (310, 320, 330) are installed by flip-chip bonding.

On the substrate (110), metal pads (120; 121, 122) connected to the wiring electrodes may be positioned in pairs. In Fig. 1, the shapes of the metal pads (120; 121, 122) may be illustrated in a simplified manner. On these metal pads (121, 122), a first type electrode (332; see Fig. 2) of a light-emitting element (310, 320, 330) may be electrically connected by conductive particles (500; hereinafter, first conductive particles).

At this time, the unit metal pad (120) defines a unit subpixel area and can be arranged on the wiring board (100) to define a unit subpixel.

Here, the first conductive particle (500) may have a size in the unit of micrometers (㎛). Therefore, the first conductive particle (500) may also be called a micro conductive particle or a conductive ball. The first conductive particle (500) may form an electrical connection between the metal pad (121, 122) and the light-emitting element (310, 320, 330). For example, the conductive particle (500) is applied between the metal pad (121, 122) and the light-emitting element (310, 320, 330) before forming the connection, and is then deformed by the bonding process of the metal pad (121, 122) and the light-emitting element (310, 320, 330) to form the connection (B, C). That is, the conductive particles (500) are deformed by the bonding process of the metal pads (121, 122) and the light-emitting elements (310, 320, 330) and can electrically connect the metal pads (121, 122) and the light-emitting elements (310, 320, 330).

Referring to FIG. 2, in this way, when the first conductive particle (500) is applied on a metal pad (120; 121, 122) while not being conductive and a light-emitting element (for example, a third light-emitting element; 330) is positioned, pressure is applied so that the first conductive particle (500) is deformed and becomes conductive, thereby forming a connection portion (B, C).

At this time, a first pressure-receiving layer (200) that increases the contact area between the metal pad (120; 121, 122) and the first conductive particle (500) by the pressure applied by the first conductive particle (500) may be positioned between the wiring board (100, or board (110)) and the unit metal pad (120; 121, 122).

Meanwhile, as an exemplary embodiment, a second pressure receiving layer (331) may be positioned between the semiconductor layer of the light emitting element (310, 320, 330) and the first type electrode (332).

This second pressure-receiving layer (331) may be provided in at least two separate locations. The location of this separated second pressure-receiving layer (331) may correspond to the location of the first conductive particle (500).

The second pressure-receiving layer (331) may be positioned in a state in which it is covered by the first type electrode (332). Specifically, the second pressure-receiving layer (331) may be positioned in contact with the semiconductor layer (330), and the first type electrode (332) may be positioned in contact with the semiconductor layer (330; third light-emitting element) while covering the second pressure-receiving layer (331).

Referring to FIG. 2, it can be seen that a first pressure-receiving layer (200) is positioned between a substrate (110) and a metal pad (122), and a first conductive particle (500) is positioned between the metal pad (122) and a first type electrode (332) of a third light-emitting element (330) in a state of being deformed and having conductivity.

In addition, it can be seen that a second pressure-receiving layer (331) is positioned on the lower surface of the semiconductor layer (330; third light-emitting element), and that the first conductive particle (500) is positioned in a state of being deformed and having conductivity between the first type electrode (332) covering the second pressure-receiving layer (331) and the metal pad (122).

The first pressure-bearing layer (200) and the second pressure-bearing layer (331) may have a lower Young's modulus than at least one of the metal pad (120; 121, 122) and the wiring board (100, or board (110)).

Meanwhile, the metal pad (120; 121, 122) has a characteristic of relatively small thermal deformation and may have a thickness (t) of approximately 5 ㎛ or less. Due to this thin thickness, the shape may be deformed by pressure. In addition, due to the presence of the first pressure-receiving layer (200), the shape may change more significantly, thereby increasing the area in contact with the first conductive particle (500) (connection portion; C).

Additionally, the contact area between the first type electrode (332) and the first conductive particle (500) can increase due to the presence of the second pressure-receiving layer (331) (connection portion; B).

As such, referring to FIG. 2, the second pressure-receiving layer (331) may be covered by the first type electrode (332). In addition, the second pressure-receiving layer (331) may have a shape (connection portion; B) corresponding to the first conductive particle (500).

In this way, the first pressure-receiving layer (200) can receive the pressure applied during the electrical connection process using the first conductive particles (500) and the shape of the metal pad (120) can be deformed to increase the contact area between the first conductive particles (500). In addition, the second pressure-receiving layer (331) can receive the pressure applied during the electrical connection process using the first conductive particles (500) and the shape of the first type electrode (332) can be deformed to increase the contact area between the first conductive particles (500).

Accordingly, the first pressure-receiving layer (200) and the second pressure-receiving layer (331) may also be referred to as pressure relief layers. Hereinafter, the pressure-receiving layer may be described interchangeably with the pressure relief layer.

At least one of the first pressure-receiving layer (200) and the second pressure-receiving layer (331) may have a thickness of 300 nm or more. In addition, the first pressure-receiving layer (200) and the second pressure-receiving layer (331) may include a polymer-based material, such as epoxy, acryl, or PI (poly imide), which exhibits a large change due to pressure and thermal expansion compared to metal. For example, the first pressure-receiving layer (200) and the second pressure-receiving layer (331) may be formed of the polymer-based material as described above. In this case, the Young's modulus of the polymer-based material may be 1000 kg/cm ² or less.

The Young's modulus (stress-to-shape deformation ratio) of the first pressure-receiving layer (200) and the second pressure-receiving layer (331) may differ by at least 10 times compared to the metal pad (120; 121, 122) or the first type electrode (332). That is, the Young's modulus of the first pressure-receiving layer (200) may be 1/10 times or smaller than that of the metal pad (120; 121, 122). In addition, the Young's modulus of the second pressure-receiving layer (331) may be 1/10 times or smaller than that of the first type electrode (332).

Specific examples and effects of these pressure-bearing layers (200, 331) will be described in detail later.

FIG. 3 is an enlarged view showing a unit subpixel of a display device using a light-emitting element according to one embodiment of the present invention.

FIG. 3 shows a portion corresponding to FIG. 2, and shows a sub-pixel inside a unit pixel of a display device using a light-emitting element according to an embodiment of the present invention.

Referring to FIG. 3, in this way, when the first conductive particle (500) is applied on the metal pad (122) in a non-conductive state and a light-emitting element (e.g., a third light-emitting element; 330) is positioned, pressure is applied so that the first conductive particle (500) is deformed and becomes conductive, thereby forming a connection portion (B, C).

At this time, a first pressure-receiving layer (210) that increases the contact area between the metal pad (122) and the first conductive particle (500) by the pressure applied by the first conductive particle (500) may be positioned between the wiring board (100, or board (110)) and the unit metal pad (122).

As an exemplary embodiment, the first pressure-receiving layer (210) may include second conductive particles (211) smaller in size than the first conductive particles (500). The second conductive particles (211) may utilize at least one of metal particles or conductive polymer patterns. The first pressure-receiving layer (210) including the second conductive particles (211) may further increase the probability of electrical connection by the first conductive particles (500).

Meanwhile, as an exemplary embodiment, a second pressure receiving layer (333) may be positioned between the semiconductor layer of the light emitting element (310, 320, 330) and the first type electrode (332).

This second pressure-receiving layer (333) may be positioned so as to be covered by the first type electrode (334). Specifically, the second pressure-receiving layer (333) may be positioned in contact with the semiconductor layer (330), and the first type electrode (334) may be positioned so as to cover this second pressure-receiving layer (333).

According to the present embodiment, the second pressure-receiving layer (333) may include third conductive particles (333a) smaller in size than the first conductive particles (500). The third conductive particles (333a) may utilize at least one of metal particles or conductive polymer patterns. Due to the second pressure-receiving layer (333) including the third conductive particles (333a), the probability of electrical connection by the first conductive particles (500) may be further increased.

Referring to FIG. 3, it can be seen that a first pressure-receiving layer (210) is positioned between a substrate (110) and a metal pad (122), and a first conductive particle (500) is positioned between the metal pad (122) and a first type electrode (334) of a third light-emitting element (330) in a state of being deformed and having conductivity.

In addition, it can be seen that a second pressure-receiving layer (333) is positioned on the lower surface of the semiconductor layer (330; third light-emitting element), and that the first conductive particle (500) is positioned in a state of being deformed and having conductivity between the first type electrode (334) covering the second pressure-receiving layer (333) and the metal pad (122).

Other details may be the same as those described above with reference to Figures 1 and 2, and therefore, redundant descriptions are omitted.

FIG. 4 is an enlarged view showing a unit subpixel of a display device using a light-emitting element according to another embodiment of the present invention.

FIG. 4 shows a portion corresponding to FIG. 2, and shows a sub-pixel inside a unit pixel of a display device using a light-emitting element according to an embodiment of the present invention.

Referring to FIG. 4, in this way, when the first conductive particle (500) is applied on the metal pad (123) in a non-conductive state and a light-emitting element (e.g., a third light-emitting element; 330) is positioned, pressure is applied so that the first conductive particle (500) is deformed and becomes conductive, thereby forming a connection portion (D, E).

At this time, a first pressure-receiving layer (220) that increases the contact area between the metal pad (123) and the first conductive particle (500) by the pressure applied by the first conductive particle (500) may be positioned between the wiring board (100, or board (110)) and the unit metal pad (123).

As an exemplary embodiment, the first pressure-receiving layer (220) may have a protrusion shape positioned between individual conductive particles (500). In this way, the first pressure-receiving layer (220) having the protrusion shape may be divided and positioned on the substrate (110). When pressure is applied in this state, the first conductive particles (500) may be positioned between the first pressure-receiving layers (220) having the protrusion shape. Accordingly, a connection portion (E) shape may be formed.

Meanwhile, as an exemplary embodiment, a second pressure receiving layer (335) may be positioned between the semiconductor layer of the light emitting element (310, 320, 330) and the first type electrode (332).

This second pressure-receiving layer (335) may be positioned so as to be covered by the first type electrode (336). Specifically, the second pressure-receiving layer (335) may be positioned so as to be in contact with the semiconductor layer (330), and the first type electrode (336) may be positioned so as to be in contact with the semiconductor layer (330) while covering the second pressure-receiving layer (335).

According to the present embodiment, the second pressure-receiving layer (335) may have a protrusion shape positioned between individual conductive particles (500). In this way, the second pressure-receiving layer (335) having the protrusion shape may be positioned in a divided manner. When pressure is applied in this state, the first conductive particle (500) may be positioned between the second pressure-receiving layers (335) having the protrusion shape. Accordingly, a connection portion (D) shape may be formed.

The protrusion shape of the second pressure-receiving layer (335) can be positioned at a position corresponding to the protrusion shape of the first pressure-receiving layer (220). Accordingly, the position of the first conductive particle (500) can be defined.

Other details may be the same as those described above with reference to Figures 1 and 2, and therefore, redundant descriptions are omitted.

LEDs, which are high-brightness elements, are being used not only for lighting but also as pixels in signage display devices. One example of a method for mounting LEDs on PCBs in display devices is using soldering.

The soldering method has the advantage of being easy to pattern through screen printing and having good environmental reliability for electrical bonding. On the other hand, it is difficult to print precisely using screen printing, and if the gap between the LED electrode pad and the electrode pad of the wiring board becomes narrow, the possibility of an electrical short circuit increases, so it is usually used when the minimum gap between the pads is 50 ㎛ or more.

Accordingly, an electrical connection method is being used by printing a liquid material containing conductive particles such as ACP (anistropic conductive paste). This method enables electrical connection without major problems even when the gap between pads is narrow.

In cases where the device has a size of 50 ㎛ or less, such as a micro LED, electrical contact due to randomness, such as with ACP, is difficult, and a method of fixing conductive particles, such as ICP (immovable conductive paste), to a certain area can be used.

When electrical connection is made using conductive particles, since the conductive particles have a structure in which they are fixed by polymer resin, peeling between the interfaces of different materials may occur due to shrinkage and expansion during the subsequent high-temperature process.

Therefore, when a heat treatment process is performed at a temperature of approximately 260 degrees after an electrical connection is made using conductive particles, a situation may occur in which the conductive particles are separated from the electrode pad.

However, according to the embodiment of the present invention as described above, reliability against high-temperature thermal shock, etc. can be improved after forming an electrical connection between the light-emitting element and the electrode pad using conductive particles.

That is, a reliable and stable electrical connection can be secured between the light-emitting element and the electrode pad.

Specifically, even when a heat treatment process is performed at a temperature of approximately 260 degrees after an electrical connection is made using conductive particles, the conductive particles do not become separated from the electrode pad, and a reliable and stable electrical connection can be made.

In addition, this embodiment of the present invention can be effectively used in cases where the size of a micro LED is 50 ㎛ or less, and where the spacing between pads is 50 ㎛ or less.

FIGS. 5 and 6 are cross-sectional views showing unit pixels of a display device using a light-emitting element according to the second embodiment of the present invention.

Fig. 5 shows an example of a unit package (301) capable of implementing a unit pixel. This unit package (301) may correspond to a unit package (301) in which the first light-emitting element (310), the second light-emitting element (320), and the third light-emitting element (330) described above are implemented as a single chip.

Such a unit package (301) may include at least one electrode pad (350, 351), a pressure-receiving layer (337) positioned on the electrode pad (350, 351), a device structure (341, 342, 310, 320, 330) positioned on the pressure-receiving layer (337), and a through-electrode (343) penetrating the pressure-receiving layer (337) and connected to the electrode pad (350, 351) and the device structure (341, 342, 310, 320, 330).

At this time, the element structure may include a connection pad (341, 342) connected to a through electrode (343) and a light-emitting element (310, 320, 330) connected to the connection pad (341, 342).

As an exemplary embodiment, the electrodes of the light emitting elements (310, 320, 330) can be connected to the connection pads (341, 342) by the second conductive particles (510).

Additionally, the device structure may further include a transparent cover layer (370) on the light-emitting device (310, 320, 330).

Referring to FIG. 6, a unit package (301) having such a structure can be electrically connected to a wiring board (100) including a substrate (110) having unit metal pads (124, 125) by first conductive particles (500). An insulating layer (410) can be provided between the unit package (301) and the wiring board (100).

At this time, the pressure-receiving layer (337) can increase the contact area between the electrode pad (350, 351) and the first conductive particle (500) by the pressure applied by the first conductive particle (500).

By means of such a pressure-receiving layer (337), the shape of the connection portion (B, C, D, E) described above with reference to FIGS. 2 to 4 can be formed between the electrode pad (350, 351) and the first conductive particle (500), but is omitted in FIG. 6.

FIG. 7 and FIG. 8 are cross-sectional views showing unit pixels of a display device using a light-emitting element according to a third embodiment of the present invention.

Fig. 7 shows another example of a unit package (301) capable of implementing a unit pixel. This unit package (301) may correspond to a unit package (301) in which the first light-emitting element (310), the second light-emitting element (320), and the third light-emitting element (330) described above are implemented as one chip.

Such a unit package (301) may include at least one electrode pad (350, 351), a pressure-receiving layer (337) positioned on the electrode pad (350, 351), a device structure (341, 342, 310, 320, 330) positioned on the pressure-receiving layer (337), and a through-electrode (343) penetrating the pressure-receiving layer (337) and connected to the electrode pad (350, 351) and the device structure (341, 342, 310, 320, 330).

At this time, the element structure may include a connection pad (341, 342) connected to a through electrode (343) and a light-emitting element (310, 320, 330) connected to the connection pad (341, 342).

As an exemplary embodiment, the electrodes of the light emitting elements (310, 320, 330) can be connected to the connection pads (341, 342) by soldering.

Referring to FIG. 8, a unit package (301) having such a structure can be electrically connected to a wiring board (100) including a substrate (110) having unit metal pads (124, 125) by first conductive particles (500).

Any parts not described above may be identical to those of the embodiment described above with reference to FIGS. 5 and 6. Therefore, any duplicate description is omitted.

Fig. 9 is a cross-sectional view showing a unit pixel of a display device using a light-emitting element according to the fourth embodiment of the present invention.

Fig. 9 illustrates another example of a unit package (302) capable of implementing a unit pixel. This unit package (302) may correspond to a unit package (302) in which an integrated circuit chip (IC) (380) is implemented. For example, this integrated circuit chip (380) may correspond to a driving chip that drives the light-emitting element (310, 320, 330) described above or another unit package (301).

Such a unit package (302) may include at least one electrode pad (344), a pressure-receiving layer (338) positioned on the electrode pad (344), a device structure (380) positioned on the pressure-receiving layer (338), and a through-electrode (345) penetrating the pressure-receiving layer (338) and connected to the electrode pad (344) and the device structure (380).

That is, the device structure may include an integrated circuit chip (380) connected to a through electrode (345).

Referring to FIG. 9, a unit package (302) having such a structure can be electrically connected to a wiring board (100) including a substrate (110) having a unit metal pad (126) by first conductive particles (500).

Any parts not described above may be identical to those of the embodiments described above with reference to FIGS. 5 to 8. Therefore, any duplicate description is omitted.

FIG. 10 is a photograph showing a unit pixel of a display device using a light-emitting element according to the first embodiment of the present invention.

Referring to FIG. 10, it can be seen that the shape changes more significantly due to the presence of the first pressure-receiving layer (200), so that the contact area between the first conductive particle (500) and the metal pad (122) increases, thereby forming a curved connection portion (C).

Figure 10 shows the state after a heat treatment process is performed at a temperature of about 260 degrees after such electrical connection is made, and it can be confirmed that there is no change in the electrical connection state even after the high-temperature heat treatment.

The above description is merely an example of the technical idea of the present invention, and those skilled in the art will appreciate that various modifications and variations may be made without departing from the essential characteristics of the present invention.

Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to explain it, and the scope of the technical idea of the present invention is not limited by these embodiments.

The scope of protection of the present invention should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

100: Wiring board 110: Board
120, 121, 122: Metal pad 200, 210, 220: First pressure-receiving layer
300: Unit pixel 310, 320, 330: Light emitting element
331, 333, 335, 337: Second pressure receiving layer

Claims (13)

wiring board;
A unit metal pad defining a unit subpixel area and arranged on the wiring board to form a unit subpixel;
A light emitting element in which a first type electrode positioned on a semiconductor layer is electrically connected to the unit metal pad by first conductive particles; and
A display device using a light-emitting element, characterized in that it comprises a first pressure-receiving layer positioned between the wiring board and the unit metal pad, and which increases a contact area between the metal pad and the first conductive particle by pressure applied by the first conductive particle. A display device using a light-emitting element, characterized in that in the first paragraph, the first pressure-receiving layer has a Young's modulus smaller than at least one of the metal pad and the wiring substrate. A display device using a light-emitting element, characterized in that in claim 1, the first pressure-receiving layer includes second conductive particles having a smaller size than the first conductive particles. A display device using a light-emitting element, characterized in that in claim 1, the first pressure-receiving layer has a protrusion shape positioned between the individual first conductive particles. A display device using a light-emitting element, characterized in that in claim 1, a second pressure-receiving layer is positioned between the semiconductor layer of the light-emitting element and the first type electrode. A display device using a light-emitting element, characterized in that in claim 5, the second pressure-receiving layer is covered by the first type electrode. A display device using a light-emitting element, characterized in that in claim 5, the second pressure-receiving layer includes third conductive particles having a smaller size than the first conductive particles. A display device using a light-emitting element, characterized in that in claim 5, the second pressure-receiving layer has a protrusion shape positioned between individual conductive particles. wiring board;
Unit metal pads arranged on the above wiring board; and
A unit package comprising a unit metal pad and a first conductive particle electrically connected thereto;
The above unit package is,
At least one electrode pad;
A pressure-receiving layer positioned on the above electrode pad;
A device structure positioned on the pressure-receiving layer; and
A penetrating electrode is included that penetrates the pressure-receiving layer and is connected to the electrode pad and the element structure.
A display device using a light-emitting element, characterized in that the pressure-receiving layer increases the contact area between the electrode pad and the first conductive particle by the pressure applied by the first conductive particle. In the 9th paragraph, the element structure is,
a connection pad connected to the above penetrating electrode; and
A display device using a light-emitting element, characterized by including a light-emitting element connected to the above-mentioned connection pad. A display device using a light-emitting element, characterized in that in claim 9, the electrode of the light-emitting element is connected to the connecting pad by the second conductive particle. A display device using a light-emitting element, characterized in that in claim 9, the element structure includes an integrated circuit chip connected to the through-electrode. A display device using a light-emitting element, characterized in that in claim 9, the pressure-receiving layer has a Young's modulus smaller than at least one of the electrode pad and the wiring substrate.

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