KR20180105803A - method for fabricating LED module - Google Patents

Abstract

The present invention relates to a method for manufacturing an LED module, which comprises: a chip-on carrier manufacturing process of manufacturing a chip-on carrier including a chip holding unit having a horizontal adhesive surface and a plurality of LED chips having electrode pads attached to the adhesive surface of the chip holding unit; and a transfer printing process of transferring the LED chips at a predetermined array to a substrate placed in a different position from the chip holding unit. The transfer printing process includes: a first UV exposure step of regionally exposing a transfer tape to UV light weakening adhesive force of the transfer tape to form adhesive regions in the transfer tape at predetermined intervals; and a chip pickup step of pressing the transfer tape to the LED chips on the chip holding unit to attach each of the LED chips to each of the adhesive regions of the transfer tape, and also, separating the electrode pads of the LED chips from the chip holding unit.

Description

[0001] The present invention relates to a method for fabricating LED module,

The present invention relates to a method of manufacturing an LED module using transfer printing and flip bonding.

A full-color LED display device has been proposed in which each of LEDs emitting different wavelengths is grouped to constitute a pixel instead of a display device in which the LED is used as a backlight source. At this time, each pixel is composed of a red LED, a green LED, and a blue LED, or a red LED, a green LED, a blue LED, and a white LED. In such an LED display device, each of red LED, green LED, and blue LED is packaged and mounted on a substrate. In this case, it is difficult to obtain a high quality resolution because the LEDs constituting each pixel are separated from each other. When pixels are formed by package-type LEDs, it has been difficult to apply them to a micro-LED display device which has recently been attracting attention. Also, conventionally, an LED pixel unit in which a red LED, a green LED, and a blue LED that constitute one pixel are mounted in one package has been proposed. In this case, the spacing between the LEDs in one pixel, i.e., the spacing between sub-pixels, is reduced, but it is difficult to reduce the spacing between pixels. Further, interference of light may occur between the red LED, the green LED, and the blue LED.

Accordingly, the inventors of the present invention have attempted to implement an LED display module by arraying groups including a red LED chip, a green LED chip, and a blue LED chip on a PCB substrate in a matrix array in order to reduce a space between pixels. However, it has been difficult to mount LED chips having micrometer-scale fine size on a substrate so as to have a constant height and a constant interval. The difference in height and spacing of the LED chips mounted on the substrate deteriorates the color reproducibility. In addition, wire bonding was required for electrical connection between the electrode pads on the substrate and the LED chip. Because of such wire bonding, it takes at least several tens to several hundreds of hours to manufacture one product. Particularly, in the process of mounting several tens to several hundred LED chips on a substrate, the LED chip is not accurately positioned at a desired position, and a target luminescent pattern can not be realized at the time of designing, and severe color deviation occurs. In particular, recently, a technique of manufacturing an LED module for display by arraying micro LEDs having a size of several to several hundreds of micrometers on an AM matrix substrate has been used, but it has been difficult to manufacture a precise and high quality display module by the conventional chip mounting method.

On the other hand, a technique of transferring LED chips arrayed at arbitrary positions onto other substrates by using total transfer printing can be a solution to the problems of the prior art. However, even if the LED chips having the electrode pads on the upper side are transferred to the substrate by transfer printing and arrayed, if there is a separate additional process such as wire bonding, the number of processes increases and the production cost increases. It will be bad. Therefore, when the flip-bonding type LED chips arranged with the electrode pads facing downward are transferred and printed onto the substrate, a separate additional process such as wire bonding is not required and the additional process prevents the arrangement from being disturbed . In addition, it is necessary to select LED chips having a desired size of several to several hundreds of micrometers in a desired arrangement and array them by transfer printing.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method and apparatus for transferring and printing a plurality of LED chips onto a substrate from a chip holding unit that holds a plurality of LED chips unrestrictedly, The selected LED chip can be transferred and printed onto the substrate by locally reducing the adhesive force of the transfer tape used for transferring the LED chip from the chip holding part to the substrate side by UV light, in particular, UV-A light. And a method for manufacturing the LED module.

An LED module according to one aspect of the present invention includes: a plurality of LED chips having an electrode pad on one side and a surface bonded to a transfer tape on the other side; And a substrate having a plurality of bumps flip-bonded to the electrode pad, wherein the transfer tape is divided into an exposed region and a non-exposed region by primary light emitted from the outside to the other side of the LED chip, The area is picked up by bonding the LED chip to the adhesive area.

According to one embodiment, the adhesive region is separated from the LED chip by the secondary light emitted from the outside to the other side of the LED chip.

According to an embodiment, the light radiated from the outside to the LED chip side weakens the adhesive force of the transfer tape with UV light.

According to one embodiment, the light radiated from the outside to the LED chip side weakens the adhesive force of the transfer tape with a laser.

According to one embodiment, the adhesion regions may be regions that are not exposed to the light emitted from the outside to the LED chip side using a photomask.

According to an embodiment, the pickup picks up the LED chip by rotating the transfer tape while pressing the transfer tape onto the LED chip using a roller.

According to one embodiment, the LED chip is aligned with the seating position on the substrate and then separated from the transfer tape through the pressure rotation of the roller.

According to an aspect of the present invention, there is provided a method of manufacturing a chip-on-carrier including a chip-holding portion having a horizontal bonding surface and a plurality of LED chips having electrode pads bonded to the bonding surface of the chip- And a transfer printing process for transferring the plurality of LED chips to a predetermined arrangement from the chip holding unit to a substrate at a different position from the chip holding unit, wherein the transfer printing process comprises: transferring the transfer tape onto the transfer tape, A first UV exposure step of exposing the transfer tape to the adhesive regions at predetermined intervals on the transfer tape; And the transfer tape is pressed against the LED chips on the chip holding part to attach each of the LED chips to each of the adhesive areas of the transfer tape while separating the electrode pads of the LED chip from the chip holding part , And a chip pickup step.

According to one embodiment, the primary UV exposure step locally irradiates the transfer tape with UV light at a wavelength of 320 to 380 nm.

According to one embodiment, the primary UV exposure step may include placing a photomask having a plurality of UV light transmission windows formed directly on or under the transfer tape, and exposing the UV light to the transfer tape through the UV light transmission window .

According to one embodiment, the method of fabricating the LED module further includes, after the chip picking step, a secondary UV exposure step of exposing the transfer tape with the LED chips attached thereto to UV light to weaken the adhesive force of the adhesive areas .

According to one embodiment, the method of fabricating the LED module further includes, after the chip pick-up step, exposing the transfer tape to which the LED chips are attached with UV light of 320 to 380 nm, And an exposure step.

According to another embodiment of the present invention, there is provided a method of manufacturing an LED module, the method comprising: after the chip picking step, weakening an adhesion force of the transfer tape to which the LED chips are attached, Lt; RTI ID = 0.0 > chip < / RTI >

According to one embodiment, the chip picking step presses the transfer tape onto each of the LED chips that are bonded onto the chip holding portion by a pick-up roller that rolls in one direction.

According to one embodiment, the transfer tape comprises a UV curable adhesive material on the adhesive side which is cured by UV light to weaken the adhesive strength.

According to another embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: after the chip picking step, weakening the adhesive force of the transfer tape to which the LED chips are attached as a whole; Down step includes pressing the LED chips attached to the transfer tape with aplacing roller onto the substrate so that electrode pads of the LED chips are electrically connected to bump pairs formed on the substrate in advance Respectively.

According to one embodiment, the adhesive force of the transfer tape in the flipping step is smaller than the adhesive force of the adhesive preliminarily applied to the bump pair.

According to one embodiment, the chip-on-carrier fabrication process comprises: preparing a chip holding portion having a horizontal bonding surface; Preparing a plurality of LED chips; And attaching the plurality of LED chips to the adhesive surface so as to form at least one LED chip array, wherein the step of preparing the plurality of LED chips comprises the steps of: forming an n-type electrode pad and a p- And the chip attaching step directly bonds the n-type electrode pad and the p-type electrode pad to the bonding surface.

According to an embodiment, the step of attaching chips may be performed such that the pitch in the LED chip array on the chip holding unit is 1 / n times the pitch in the LED chip array transferred to the substrate by the transfer printing process, Wherein n is a number greater than 1 and said pitch is the horizontal distance between one LED chip center and another LED chip center in the neighboring two LED chips.

According to another aspect of the present invention, there is provided an LED module including: a substrate having bumps; And a plurality of LED chips that are flip-bonded to the substrate such that the electrode pads are transferred to the substrate at an arbitrary position and the electrode pads are connected to the bumps, wherein the LED chips are mounted on the substrate In order to transfer the transfer tape, there is used a transfer tape in which the adhesive force is weakened by UV light, and the transfer tape is formed such that adhesive areas not exposed to UV light adhere to the LED chips and pick up from the arbitrary position, When the adhesive force of the adhesive regions is weakened, they are separated from the LED chips.

A method for fabricating an LED module according to the present invention includes transferring and printing a plurality of LED chips from a chip holding unit that holds the LED chips to a predetermined arrangement without fluttering and then flip-bonding the plurality of LED chips onto the substrate to manufacture an LED module , The adhesive force of the transfer tape used for transferring the LED chip from the chip holding part to the substrate side is locally reduced by UV light, in particular UV-A light, so that only the selected LED chip can be precisely transferred and printed onto the substrate have.

1 is a flow chart for explaining a method of manufacturing an LED module.
FIG. 2 is a view for explaining the transfer printing process in the LED module manufacturing method shown in FIG.
3 is a view for explaining a chip-on-carrier manufacturing process including a blue LED chip.
4 is a view for explaining a chip-on-carrier manufacturing process including a green LED chip.
5 is a view for explaining a chip-on-carrier manufacturing process including a red LED chip.
6 is a view illustrating a chip-on-carrier manufacturing process including a red LED chip, a green LED chip, and a blue LED chip according to another embodiment of the present invention.

Hereinafter, a display module having LED chip arrays of different wavelengths according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the present specification, the same reference numerals are assigned to the same components in different embodiments, and the description thereof is replaced with the first explanation.

2 is a view for explaining a transfer printing process in the method of manufacturing the LED module shown in FIG. 1, and FIG. 3 is a view for explaining a process of manufacturing a chip-on-carrier including a blue LED chip 4 is a view for explaining a chip-on-carrier manufacturing process including a green LED chip, FIG. 5 is a view for explaining a chip-on-carrier manufacturing process including a red LED chip, and FIG. A chip-on-carrier manufacturing process including a red LED chip, a green LED chip, and a blue LED chip according to another embodiment of the present invention.

Referring to FIGS. 1 and 2, a method of manufacturing an LED module according to an embodiment of the present invention includes a chip holding portion 2 having a horizontal bonding surface, and a chip holding portion 2 bonded to the bonding surface of the chip holding portion 2 A chip-on-carrier manufacturing process (S1) for manufacturing a chip-on-carrier (COC) including a plurality of LED chips (1) And a transfer printing step S2. The chip-on-carrier fabrication process S1 includes a step of forming a plurality of electrode pads 122 and 142, that is, an n-type electrode pad 122 and a p-type electrode pad 142 facing downward, On carriers (COCs) which can be very advantageously used for an LED chip array using transfer printing, because the LED chips 1 of the LED chips 1 are kept in a constant arrangement without any disturbance. Further, the chip-on-carrier (COC) is determined by 1 / n of the inter-chip pitch of the LED chips in the one-column array in which the inter-chip pitch P of the LED chips 1 is arrayed on the substrate by the transfer printing described above, n is a natural number of 1 or more. In this specification, chip pitch is defined as a horizontal distance between one LED chip center and another LED chip center in two neighboring LED chips. In this way, front-side transfer printing in which the LED chips 1 in the LED chip array held in the chip holding portion 2 are transferred onto the substrate as a whole and the LED chips 1 in the LED chip array held in the chip holding portion 2, Lt; RTI ID = 0.0 > selectively < / RTI > transferring some of the LED chips onto the substrate.

As described above, the transfer printing process S2 is performed by selecting all or a part of the plurality of LED chips 1 attached to the chip holding portion 2 of the chip-on-carrier (COC) ). ≪ / RTI > In other words, in the transfer printing process S2, the LED chips 1 may be transferred and printed on the substrate 5 as they are arranged in the LED chip array of the chip-on-carrier (COC) (COC) LED chip 1 so that the arrangement pitch of the LED chip 1 of the LED chip array transferred to the chip-on-carrier (COC) is n times the pitch of the LED chip 1 of the chip- May be selected and transferred onto the substrate 5.

This transfer printing step S2 is a step of exposing the transfer tape 3 to the UV light which weakens the adhesive force of the transfer tape and exposing the transfer tape 3 to the primary UV The LED chip 1 is attached to each of the adhesive regions 32 of the transfer tape 3 by pressing the transfer tape 3 against the LED chips 1 of the chip- The transfer tape 3 is exposed to the UV light which weakens the adhesive force of the transfer tape 3 so as to weaken the adhesive strength of the adhesive regions 32 of the transfer tape 3, A UV exposure step S23 and a flushing down step S24 for pressing the LED chips 1 adhered to the transfer tape 3 whose adhesion is weakened to the substrate 5. During the flaking down step S24 or after the flaking step S24, the peeling step S25 for detaching the transfer tape 3 from the LED chip 1 is performed.

First, in the first UV exposure step S21, a photomask 220 in which a plurality of UV light transmitting windows 222 are formed at regular intervals on the upper side or directly below the transfer tape 3 is disposed. The first UV light source 230 emits UV light to the transfer tape 3 through the UV light transmission window 222 or in other words from the first UV light source 230 which has passed through the UV light transmission window 222 The transfer tape 3 is exposed to the UV light of the UV light to weaken the adhesive force of the areas of the transfer tape 3 exposed to the UV light. As a result, only the regions outside the region where the adhesive force is weakened become the adhesive regions 32, and these adhesive regions 32 have a constant spacing. Preferably, the first UV light source 230 emits UV light having a peak wavelength of 320 to 380 nm, and the transfer tape 3 includes a UV curable adhesive material which is cured by UV light to weaken the adhesive strength Do. The interval of the adhesion area of the transfer tape 3 can be determined in accordance with the interval of the UV light transmission window 222 of the photomask 220. [

Next, the chip pick-up step S22 presses the transfer tape 3 onto the chip 1 held on the chip holding portion 2 by the pick-up roller 240 which rolls in one direction. In this embodiment, the first stage 200 supporting the chip-on-carrier (COC) rises, while the pickup roller 240 rotates in one direction, and the chip-carrier (COC) The LED chips 1 attached to the transfer tape 3 are bonded to the adhesive regions 32 of the transfer tape 3. [ At this time, the sapphire substrate of the LED chip 1 is directly bonded to the transfer tape 3.

In this example, since the adhesive regions 32 of the transfer tape 3 are determined corresponding to the number and pitch of the LED chips 1 in the LED chip array of chip-on-carrier (COC) in the preceding primary UV exposure step S21 , The LED chips 1 are picked up at a ratio of 1: 1, but in the first exposure step S21, when the adhesive regions 32 expand the pitch, only some of the LED chips 1 are selectively picked up. That is, the LED chips 1 can be picked up at a ratio of n: 1 (where n> 1). The rolling of the pickup roller 240 may be realized by a translational movement of the rotating pickup roller 240 itself or may be realized by translating the stage 200 while the pickup roller 240 rotates in place . At this time, the pickup roller 240 may have a flexible blanket on the outer circumferential side of the roller body coupled with the shaft. When the blanket is provided, the LED chip 1 is attached to the transfer tape 3 more And it is also possible to prevent damage to the LED chip 1 due to pressure. The bonding area 32 of the transfer tape 3 is larger than the chip holding force or adhesive force of the chip holding part 2 so that the selected LED chip 1 can be attached to and held by itself. The LED chip 1 is not attached to regions of the transfer tape 3 outside the adhesive region 32, that is, in regions where the adhesive force is weakened by the UV light.

The secondary UV exposure step S23 exposes the transfer tape 3 carrying the selected LED chip 1 to the UV light which weakens the adhesive force of the transfer tape 3 to form the adhesive region 32 of the transfer tape 3 ). A second UV light source 260 may be disposed in the middle of the flow path of the transfer tape 3 or in the vicinity of the flipping roller 270. The second UV light source 260 may irradiate the transfer tape 3 with UV light The adhesive strength of the entire area of the carrier tape 3 including the adhesive regions 32 holding the LED chips 1 can be weakened. The second UV light source 260 preferably emits UV light having a peak wavelength of 320 to 380 nm.

The flipping down step S24 includes pressing the LED chips 1 adhered to the transfer tape 3 whose adhesion is weakened against the substrate 5. [ The transfer tape 3 to which the LED chips 1 are attached is moved between the plate 5 on which the splicing roller 270 and the bump pairs 5b are formed in advance. At this time, the adhesive force of the transfer tape 3 that has undergone the secondary UV exposure step S23 is smaller than the adhesive force of the adhesive previously put on the substrate 5, more specifically, the bump pairs 5a and 5b. The plucking roller 270 rotates to rotate the LED chips 1 attached to the transfer tape 3 onto the substrate 5 and more specifically to the pairs of bumps 5a and 5b on the substrate 5. [ And attaches the LED chips 1 to the substrate 5. [ The flipping roller 270 is provided with a flexible blanket on the outer circumferential side of the roller body coupled with the shaft, which allows the LED chip 1 to be flushed down more by the rolling rotation, Thereby preventing the LED chip 1 from being damaged by the LED chip 1. In addition, the second stage 290 can be raised to help pressurize by the pleated roller 270. Next, a peeling step (s25) of peeling off the transfer tape 3 from the LED chip 1 is performed, and then the LED chips 1 flushed down on the substrate 5 are subjected to a subsequent reflow soldering process To be bonded to the substrate.

3, the chip-on-chip carrier manufacturing process including the blue LED chip 1B is performed on the sapphire substrate 10B and the sapphire substrate 10B, and the n-type semiconductor layer 12B, the active layer 13B, and the p- An LED wafer manufacturing step S11-B for fabricating a blue LED wafer WB including a gallium nitride epitaxial layer including the semiconductor layer 14B, a wafer patterning step S12-B for patterning the epilayer so that a plurality of blue light emitting cells CB including an exposed region of the n-type semiconductor layer 12B on the opposite side of the sapphire substrate 10B are formed in a matrix array; a pad forming step S13-B in which a p-type electrode pad 142B is formed in an exposed region of the p-type semiconductor layer 14B and an n-type electrode pad 122B is formed in an exposed region of the n- ), The LED wafer WB is singulated in units of the light emitting cells CB, A p-type electrode pad 142B formed on the wafer layers 12B, 13B and 14B on the sapphire substrate 10B and a wafer layer 12B, 13B and 14B on the opposite side of the sapphire substrate 10B, a chip dividing step S14-B of fabricating a plurality of blue LED chips 1B including the n-type electrode pads 122B and a plurality of blue LED chips 1B, The chip attaching step S15-B, in which the electrode pad 122B is turned downward and attached onto the chip holding portion 2 having an adhesive force so that the plurality of blue LED chips 1B are arranged in a matrix array, . The adhesive force of the chip holding portion 2 is smaller than the adhesive force of the transfer tape 3 before UV exposure and the adhesive force of the transfer tape 3 after UV exposure.

In the blue LED wafer fabrication step S11-B, the epitaxial layer is grown so that the active layer 13B includes an InxGa (1-x) N well layer, but the amount of In is appropriately adjusted to obtain the blue LED chip 1B . In the wafer patterning step (S12-B), a plurality of row-directional bones and a plurality of column-direction bones are formed by etching on the epi-layer to form an n-type semiconductor layer 11B on the sapphire substrate 10B or the lattice- The active layer 13B and the p-type semiconductor layer 14B are first formed and then the p-type semiconductor layer 14B of each light emitting cell CB, the active layer 13B 13B are partially etched away to expose the n-type semiconductor layer 12B. In the pad forming step S13-B, the p-type electrode pad 142B is formed in the exposed region of the p-type semiconductor layer 14B and the n-type electrode pad 122B is formed in the exposed region of the n- The n-type electrode pad 122B is formed to have a thickness that compensates for the above-mentioned step so that the height from the bottom surface of the sapphire substrate 10B to the top surface of the n-type electrode pad 122B is equal to the top surface of the p- (122B) and the p-type electrode pad (142B). The chip dividing step S14-B may be performed by dividing the blue LED wafer WB into units of the light emitting cells CB using a cutting tool T or a laser such as a blade or a saw A plurality of blue LED chips 1B are fabricated. Up to this stage, the n-type electrode pad 122B and the p-type electrode pad 142B face upward and the sapphire substrate 10B faces downward. In the chip attaching step S15-B, the plurality of blue LED chips 1B are turned upside down so that the n-type electrode pad 122B and the p-type electrode pad 142B are bonded to the horizontal bonding surface of the chip holding portion 2B A plurality of blue LED chips 1B are mounted on the chip holding portion 2B so that the blue LED chips 1B are arranged. At this time, the top surface of the LED chips 1 is the base surface of the sapphire substrate 10B, and the height of all the blue LED chips 1B is constant based on the bonding surface of the chip holding portion 2B. All the blue LED chips 1B of the chip-on-carrier thus manufactured are arranged on the chip holding portion 2B to form a plurality of row arrays or columnar arrays. The chip holding portion 2B is preferably a chip holding film having flexibility and having a horizontal bonding surface. The inter-chip pitch P of the blue LED chips 1B in the specific one-column array adhered to the horizontal bonding surface of the chip holding portion 2B is set so that the inter-chip pitch P of the blue LED chips 1B in the one-column array arrayed on the substrate by the above- Is set to 1 / n of the inter-chip pitch of the LED chips, where n is a natural number of 1 or more. In this specification, chip pitch is defined as a horizontal distance between one LED chip center and another LED chip center in two neighboring LED chips.

4, the chip-on-chip carrier manufacturing process including the green LED chip 1G is performed on the sapphire substrate 10G and the sapphire substrate 10G, and the n-type semiconductor layer 12G, the active layer 13G, and the p- An LED wafer manufacturing step S11-G for fabricating a green LED wafer WG including a gallium nitride epitaxial layer including the semiconductor layer 14G, a wafer patterning step S12-G for patterning the epilayer so that a plurality of green light emitting cells CG including an exposed region of the n-type semiconductor layer 12G on the opposite side of the sapphire substrate 10G are formed in a matrix array; a pad forming step S13-G for forming a p-type electrode pad 142G in an exposed region of the p-type semiconductor layer 14G and an n-type electrode pad 122G in an exposed region of the n- ), The LED wafer WG is singulated in units of light emitting cells (CG), and a sapphire substrate A p-type electrode pad 142G formed on the wafer layers 12G, 13G and 14G on the sapphire substrate 10G and on the wafer layers 12G, 13G and 14G on the opposite sides of the sapphire substrate 10G, a chip dividing step S14-G for fabricating a plurality of green LED chips 1G including the n-type electrode pads 122G, a plurality of green LED chips 1G, The chip attaching step S15-G, in which the electrode pads 122B are turned downward and attached on the chip holding part 2 having an adhesive force so that the plurality of green LED chips 1G are arranged in a matrix array, .

In the green LED wafer fabrication step S11-G, the epitaxial layer is grown so that the active layer 13G includes the InxGa (1-x) N well layer. In order to obtain the green LED chip 1G, The composition ratio of In is controlled to be high.

In the wafer patterning step S12-G, a plurality of row-directional bones and a plurality of column-direction bones are formed by etching on the epi-layer, and the n-type semiconductor layer 11G is formed on the sapphire substrate 10G or the lattice- A plurality of light emitting cells CG including the p-type semiconductor layer 14G, the active layer 13G and the p-type semiconductor layer 14G are first formed and then the p-type semiconductor layer 14G, the active layer 13G are partially etched away to expose the n-type semiconductor layer 12G. In the pad formation step S13-G, the p-type electrode pad 142G is formed in the exposed region of the p-type semiconductor layer 14G and the n-type electrode pad 122G is formed in the exposed region of the n- The thickness of the n-type electrode pad 122G is set so that the distance from the bottom surface of the sapphire substrate 10G to the top surface of the n-type electrode pad 122G is equal to the distance from the top surface of the p- (122G) and the p-type electrode pad (142G). The chip dividing step S14-G divides the LED wafer WG into the light emitting cells CG using a cutting tool T or a laser such as a blade or a saw to form a plurality of green LED chips 1G ). Up to this stage, the n-type electrode pad 122G and the p-type electrode pad 142G face upward and the sapphire substrate 10G faces downward. In the chip attaching step S15-G, the plurality of green LED chips 1G are turned upside down so that the n-type electrode pad 122G and the p-type electrode pad 142G are bonded to the horizontal bonding surface of the chip holding portion 2G A plurality of green LED chips 1G are mounted on the chip holding portion 2G so that the green LED chip 1G is mounted on the chip holding portion 2G. At this time, the upper surface of the green LED chips 1G becomes the base surface of the sapphire substrate 10G, and the height of all the green LED chips 1G is constant with reference to the bonding surface of the chip holding portion 2G. All the green LED chips 1G of the chip-on-carrier thus manufactured are arranged on the chip holding portion 2G to form a plurality of row arrays or columnar arrays. The chip holding portion 2G is preferably a chip holding film having flexibility and having a horizontal bonding surface. The inter-chip pitch P of the green LED chips 1G in the specific one-column array adhered to the horizontal bonding surface of the chip holding portion 2G is set so that the inter-chip pitch P of the blue LED Is set to 1 / n of the inter-chip pitch of the LED chips, where n is a natural number of 1 or more.

5, a chip-on-chip carrier manufacturing process including a red LED chip includes a sapphire substrate 10R and a p-type semiconductor layer 12R, an active layer 13R, and an n-type semiconductor layer 12R bonded on the sapphire substrate 10R. (S11-R) for fabricating a red LED wafer (WR) including an epitaxial layer including the first region (a1) and a second region (14R) A wafer patterning step S12-R for patterning the epilayer so that a plurality of red light emitting cells CR separated in the region a2 are formed in a matrix array; An n-type electrode pad 142R connected to the n-type semiconductor layer 14R is formed on the first region 14R and an n-type electrode pad 142R connected to the n-type semiconductor layer 14R is formed on the second region a2. The p-type electrode pads 122R (122R) connected to the wiring layer L extending from the p-type semiconductor layer exposure groove 120R and the n-type semiconductor layer 14R (S13-R) forming a p-type GaN layer on the sapphire substrate, a step of forming a pad S13-R for forming a sapphire substrate 10R, a red LED wafer WR in a unit of a light emitting cell CR to form a sapphire substrate 10R, A chip dividing step S14-R for manufacturing a plurality of red LED chips 1R including the p-type electrode pad 122R and the n-type electrode pad 142R, and a plurality of red LED chips 1R Is mounted on a chip holding portion 2R having an adhesive force by turning the p-type electrode pad 122R and the n-type electrode pad 142R downward so that the plurality of red LED chips 1R are arranged in a matrix arrangement (S15-R).

In the red LED wafer fabrication step S11-R, an n-type semiconductor layer 14R including an n-AlGaInP layer and an n-cladding layer, an active layer 13R including an MQW, p- cladding layer and the p-GaP epitaxial layer including a p-type semiconductor layer (12R) including a layer is grown, across the SiO ₂ bond layer (11R) serving as a support substrate to the p-type semiconductor layer (12R) Bonding the sapphire substrate 10R and separating the GaAs substrate GS, which is a growth substrate, from the n-type semiconductor layer 14R on the opposite side.

In the wafer patterning step S12-R, a plurality of row directional bones and a plurality of column direction bones are formed in the epi layer by etching to form a p-type semiconductor layer 10R on the sapphire substrate 10R or the bonding layer 11R thereon. A plurality of light emitting cells CR including the active layer 12R, the active layer 13R and the n-type semiconductor layer 14R are first formed and then the p- A plurality of p-type semiconductor layer exposure grooves 120R formed by etching to a depth reaching the GaP layer are formed so that the upper region of each light emitting cell CR includes the first region a1 and the second region a2 do. In the pad forming step s13-R, the n-type electrode pad 142R is formed on the n-type semiconductor layer 14R of the first region a1 so that the n-type electrode pad 142R is formed on the n- Type electrode pad 122R is formed on the n-type semiconductor layer 14R of the second region a2 while the p-type electrode pad 122R is directly connected to the p-type semiconductor layer exposure groove 120R Type semiconductor layer 12R by the wiring layer L extending to the p-type semiconductor layer 12R. The distance from the bottom surface of the sapphire substrate 10R to the n-type electrode pad 142R, that is, the height of the bonding surface of the n-type electrode pad 142R and the bottom surface of the sapphire substrate 10R to the p- That is, the bonding surface height of the p-type electrode pad 122R is made equal. The chip division step S14-R divides the LED wafer WR into the light emitting cells CR to manufacture a plurality of red LED chips 1R. Up to this stage, the n-type electrode pad 142R and the p-type electrode pad 122R face upward and the sapphire substrate 10R faces downward. In the chip attaching step S14-R, the plurality of red LED chips 1R are turned upside down so that the n-type electrode pad 142R and the p-type electrode pad 122R are bonded to the horizontal bonding surface of the chip holding portion 2R A plurality of red LED chips 1R are attached on the chip holding portion 2R so that the chip is held. At this time, the upper surface of the red LED chips 1R becomes the base surface of the sapphire substrate 10R, and chip-on carriers having a constant height of all the LED chips 1R are manufactured based on the bonding surface of the chip holding portion 2R. At this time, all the red LED chips 1R of the chip-on carrier are arranged on the chip holding portion 2R to form a plurality of row or column arrays.

A chip-on carrier in which a red LED chip 1R, a green LED chip 1G and a blue LED chip 1B are sequentially mounted on a chip holding portion 2 as shown in Fig. 6 may be considered. The chip-on-carrier can transfer the red LED chip 1R, the green LED chip 1G and the blue LED chip 1B onto the substrate at the same time by the above-described transfer printing process.

1, 1B, 1G, 1R: LED chips 2, 2B, 2G, 2R:
3: Transfer tape 230, 260: UV light source
240: Pickup roller 270: Placing roller
5: substrate

Claims (19)

A plurality of LED chips each having an electrode pad on one side and a surface bonded to the transfer tape on the other side; And
And a substrate having a plurality of bumps flip-bonded to the electrode pad,
Wherein the transfer tape is divided into an exposed region and a non-exposed region by primary light emitted from the outside to the other side of the LED chip, and the non-exposed region is picked up by bonding the LED chip to an adhesive region. module. The LED module according to claim 1, wherein the adhesive region is separated from the LED chip by secondary light emitted from the outside to the other side of the LED chip. The LED module according to claim 1, wherein the light radiated from the outside to the LED chip side weakens the adhesive force of the transfer tape with UV light. The LED module according to claim 1, wherein the light emitted from the outside to the LED chip side weakens the adhesive force of the transfer tape with a laser. [2] The LED module of claim 1, wherein the adhesive regions are regions that are not exposed to light emitted from the outside to the LED chip side using a photomask. The pick-up according to claim 1, wherein the pick-up rotates while pressing the transfer tape onto the LED chip using a roller to pick up the LED chip The LED module of claim 1, wherein the LED chip is aligned with a seating position on the substrate and separated from the transfer tape by a pressure rotation of the roller. A chip-on-carrier manufacturing process for fabricating a chip-on-carrier including a chip holding portion having a horizontal bonding surface and a plurality of LED chips to which electrode pads are bonded to the bonding surface of the chip holding portion; And transferring the plurality of LED chips to a predetermined array, wherein the transfer printing process comprises:
A first UV exposure step of exposing the transfer tape regionally to UV light that weakens the adhesion of the transfer tape to form adhesion regions at the predetermined intervals on the transfer tape; And
The transfer tape is pressed onto the LED chips on the chip holding part to attach each of the LED chips to each of the adhesive areas of the transfer tape while separating the electrode pads of the LED chip from the chip holding part, And a chip pick-up step. 9. The method according to claim 8, wherein the primary UV exposure step locally irradiates the transfer tape with UV light having a wavelength of 320 to 380 nm. The method according to claim 8, wherein the first UV exposure step comprises disposing a photomask on which a plurality of UV light transmission windows are formed on or directly below the transfer tape and exposing the UV light to the transfer tape through the UV light transmission window Wherein the LED module comprises a plurality of LED modules. The method according to claim 8, further comprising a secondary UV exposure step of exposing UV light to the transfer tape to which the LED chips are attached after the chip pick-up step to weaken the adhesive force of the adhesive areas Gt; The method according to claim 8, further comprising a secondary UV exposure step of exposing UV light of 320 to 380 nm to the transfer tape to which the LED chips are attached after the chip picking step to weaken the adhesive force of the adhesive areas Wherein the LED module is manufactured by a method comprising: 9. The method of claim 8, further comprising: after the chip pick-up step, weakening the adhesive force of the transfer tape to which the LED chips have been attached as a whole; and removing the plurality of LED chips from the transfer tape, Further comprising the step of: < Desc / Clms Page number 20 > The method according to claim 8, wherein the chip pick-up step presses the transfer tape onto each of the LED chips adhered on the chip holding part by a pick-up roller that rolls in one direction. 9. The method of claim 8, wherein the transfer tape comprises a UV curable adhesive material on the adhesive surface that is cured by UV light to weaken the adhesive force. 9. The method of claim 8, further comprising: after the chip pick-up step, weakening the adhesive force of the transfer tape to which the LED chips have been attached as a whole; and removing the plurality of LED chips from the transfer tape, Wherein the flipping down step comprises pressing the LED chips attached to the transfer tape with a flipping roller onto the substrate so that the electrode pads of the LED chips are attached to the bump pair formed on the substrate in advance To form an LED module. 17. The method of claim 16, wherein the adhesive force of the transfer tape in the flipping step is smaller than the adhesive force of the adhesive previously raised to the bump pair. 10. The method of claim 8, wherein the chip-on-carrier fabrication process comprises: preparing a chip holding portion having a horizontal bonding surface; Preparing a plurality of LED chips; And attaching the plurality of LED chips to the adhesive surface so as to form at least one LED chip array, wherein the step of preparing the plurality of LED chips comprises the steps of: forming an n-type electrode pad and a p- Wherein the step of attaching the chip attaches the n-type electrode pad and the p-type electrode pad directly to the adhesive surface. [19] The method of claim 18, wherein the step of attaching chips is performed such that the pitch in the LED chip array on the chip holding unit is 1 / n times the pitch in the LED chip array transferred to the substrate by the transfer printing process, Wherein n is a number greater than 1 and said pitch is a horizontal distance between one LED chip center and another LED chip center in two neighboring LED chips. ≪ RTI ID = 0.0 > Way.

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