CN115832117A - Chip transfer method and display panel - Google Patents
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- CN115832117A CN115832117A CN202111085359.XA CN202111085359A CN115832117A CN 115832117 A CN115832117 A CN 115832117A CN 202111085359 A CN202111085359 A CN 202111085359A CN 115832117 A CN115832117 A CN 115832117A
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Abstract
The invention relates to a chip transfer method and a display panel. The chip transfer method comprises the steps of providing a chip carrier plate to form a temporary bonding structure, wherein the temporary bonding structure comprises a bonding layer arranged on a chip and a through hole arranged on the chip carrier plate, and the bonding layer is connected with the inner wall of the through hole; removing the buffer layer connected with the chip carrier plate on the chip, and leaving the chip on the chip carrier plate by the bonding layer; setting the positions of a target substrate and a chip carrier plate so that one side of the chip carrier plate, which is provided with a chip, is opposite to one side of the target substrate, which is used for arranging the chip; and the bonding layer arranged on the chip to be transferred is disconnected with the through hole, so that the chip to be transferred is separated from the chip carrier plate and falls to the target substrate. The stability of the chip when the chip is peeled off the chip carrier plate is improved, so that the accuracy of chip transfer is ensured.
Description
Technical Field
The invention relates to the field of chip transfer, in particular to a chip transfer method and a display panel.
Background
Micro-LEDs (Micro Light-Emitting diodes) are a new display technology, and compared with conventional display technologies, display with Micro-LEDs as a core has the characteristics of fast response speed, autonomous Light emission, high contrast, long service life, high photoelectric efficiency, and the like.
In the Micro-LED industry, millions or even tens of millions of LED (Light-Emitting Diode) chips need to be transferred from a growth substrate to a driving backplane one or more times. In a traditional chip transfer scheme, when chips are transferred from a growth substrate, the transfer precision is not high, and deviation is easy to occur, so that yield loss is caused.
Therefore, how to improve the chip transfer accuracy in the chip transfer process is an urgent problem to be solved.
Disclosure of Invention
In view of the above-mentioned shortcomings of the related art, the present application aims to provide a chip transfer method and a display panel, which aim to solve the problem that the transfer accuracy is not high when a chip is transferred from a growth substrate.
A chip transfer method, comprising:
providing a chip carrier plate, wherein a chip is arranged on one side of the chip carrier plate;
forming a temporary bonding structure, wherein the temporary bonding structure comprises a bonding layer arranged on the chip and a through hole arranged on the chip carrier plate, and the bonding layer is connected with the inner wall of the through hole;
removing the buffer layer connected with the chip carrier plate on the chip, wherein the chip is left on the chip carrier plate by the bonding layer;
setting the positions of a target substrate and the chip carrier plate so that the side of the chip carrier plate, provided with the chip, is opposite to the side of the target substrate, used for arranging the chip;
and the bonding layer arranged on the chip to be transferred is disconnected from the through hole, so that the chip to be transferred is separated from the chip carrier plate and falls to the target substrate.
According to the chip transfer method, the temporary bonding structure is adopted, the additional bonding layer is arranged between the chip and the chip carrier plate to realize the connection of the chip and the chip carrier plate, and the buffer layer for connecting the chip and the chip carrier plate is removed when the chip is transferred, so that the chip and the chip carrier plate are combined only through the bonding layer. Therefore, the method avoids the situation that the chip is impacted by generated gas when the chip is directly stripped by removing the buffer layer, so that the chip is impacted askew, offset and the like, and improves the stability of the chip when the chip is stripped from the chip carrier plate, thereby ensuring the accuracy of chip transfer. Moreover, due to the arrangement of the through holes, even if gas is generated in the bonding layer in the process of releasing the connection with the through holes, the gas is easy to be discharged along the direction of the through holes, namely, the direction of gas impact can be controlled to a certain extent, and the chips are ensured to stably and accurately fall onto a target carrier plate.
Optionally, the forming the temporary bonding structure includes:
forming the through hole in the area of the chip on the chip carrier plate;
and forming the bonding layer connected with the inner wall of the through hole on the chip.
Optionally, the forming the through hole in the region where the chip is disposed on the chip carrier includes:
arranging a photoresist layer on one side of the chip carrier plate, which is not provided with the chip;
patterning the photoresist layer to form a temporary through hole at a position of the photoresist layer corresponding to the chip;
and etching the chip carrier plate by using the photoresist layer as a mask plate, so that the region of the chip carrier plate corresponding to the temporary through hole is removed to form the through hole.
Optionally, the forming, on the chip, the adhesive layer connected to the inner wall of the through hole includes:
removing the buffer layer of the chip in the region corresponding to the through hole;
and arranging the bonding layer in the area of the chip corresponding to the through hole.
Optionally, the adhesive layer is irradiated by laser with a predetermined wavelength band to decompose gas;
the step of removing the buffer layer connected with the chip carrier plate on the chip comprises the following steps:
irradiating the buffer layer with laser light outside the predetermined wavelength band to decompose the buffer layer;
the making the bonding layer arranged on the chip to be transferred remove the connection with the through hole comprises the following steps:
and irradiating the bonding layer by using the laser with the preset wave band so as to decompose the bonding layer.
Optionally, the setting the positions of the target substrate and the chip carrier further includes:
and enabling the distance between the chip on the chip carrier plate and the target substrate to be smaller than the length of the chip.
Optionally, the target substrate is provided with a die bonding region;
the setting of the positions of the target substrate and the chip carrier plate further comprises:
aligning the electrode of the chip on the chip carrier plate with the bonding area of the die bonding area;
after the chip to be transferred falls to the target substrate, the method further includes:
bonding the chip dropped to the target substrate with the target substrate.
It can be understood that, in some implementation processes, the chip transfer method can realize the chip transfer from the growth substrate of the chip to the circuit substrate, reduce the times of chip transfer, avoid the precision reduction caused by multiple transfers, and further ensure the high-precision transfer of the chip.
Optionally, before the chip to be transferred is detached from the chip carrier and falls to the target substrate, the method further includes:
arranging an anisotropic conductive adhesive layer on one side of the target substrate, which is provided with the die bonding area;
the bonding the chip with the target substrate includes:
and electrically connecting the chip adhered to the anisotropic conductive adhesive layer with the anisotropic conductive adhesive layer, wherein the anisotropic conductive adhesive layer limits the current to flow in the thickness direction of the anisotropic conductive adhesive layer.
It can be understood that, through setting up the anisotropic conductive adhesive layer, realize preliminary bonding to the chip that falls to the target base plate, be favorable to the stability after falling of chip to a certain extent, produce the skew when avoiding the chip to fall to the target base plate, guarantee to shift the precision.
Optionally, before the forming the temporary bonding structure, the method further includes:
and thinning the chip carrier plate to reduce the thickness of the chip carrier plate.
It will be appreciated that thinner chip carriers are more prone to forming through holes in the temporary bond structures during the chip transfer process described above.
Based on the same inventive concept, the application also provides a display panel, which comprises a light-emitting chip and a circuit substrate, wherein the light-emitting chip is transferred to a die bonding area of the circuit substrate by the chip transfer method of the example.
The light emitting chip of the display panel is high in setting precision and good in quality. In some implementation processes, the light-emitting chips of the display panel can be directly transferred to the circuit substrate from the growth substrate, the transfer times are few, the influence on the yield of the light-emitting chips is low, and meanwhile, the transfer times are fewer, and the accuracy of chip transfer is also guaranteed.
Drawings
Fig. 1 is a schematic basic flow chart of a chip transfer method according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram after a temporary bonding structure is formed according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a chip on a chip carrier according to an embodiment of the invention;
FIG. 4 is a schematic structural diagram of a temporary bonding structure formed according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of the buffer layer removed according to the embodiment of the present invention;
FIG. 6 is a schematic diagram of the structure of FIG. 4 with the buffer layer removed;
fig. 7 is a schematic diagram illustrating arrangement positions of a target substrate and a chip carrier according to an embodiment of the invention;
FIG. 8 is a schematic structural diagram of a temporary bonding structure formed according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of a basic process for forming a temporary bonding structure according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of a process for forming a via according to an embodiment of the present invention;
FIG. 11 is a schematic view of a photoresist layer being exposed according to an embodiment of the present invention;
FIG. 12 is a schematic view of the photoresist layer patterning of FIG. 11;
FIG. 13 is a schematic view of the etching of FIG. 12 to form a via;
fig. 14 is a schematic flow chart illustrating a process of forming an adhesive layer on a chip, the adhesive layer being connected to an inner wall of a through hole according to an embodiment of the present invention;
FIG. 15 is a schematic diagram of the buffer layer on the chip for removing the region corresponding to the through hole according to the embodiment of the invention;
fig. 16 is a schematic diagram illustrating an adhesive layer disposed on a region of a chip corresponding to a through hole according to an embodiment of the present invention;
FIG. 17 is a schematic diagram of a buffer layer being removed by a laser according to an embodiment of the present invention;
FIG. 18 is a schematic diagram illustrating a distance arrangement between a chip and a target substrate on a chip carrier according to an embodiment of the invention;
FIG. 19 is a schematic diagram of a chip directly transferred to a circuit substrate according to an embodiment of the present invention;
FIG. 20 is a schematic view of an anisotropic conductive adhesive layer on a target substrate according to an embodiment of the present invention;
description of reference numerals:
1-chip; 11-a buffer layer; 12-other epitaxial layers; a 121-N type semiconductor layer; 122-an active layer; 123-P type semiconductor layer; 13-an electrode; 2-an adhesive layer; 3-chip carrier plate; 4-a through hole; 5-a target substrate; 51-a circuit substrate; 52-a pad; 53-anisotropic conductive adhesive layer; 6-photoresist layer; 61-temporary vias; 7-mask plate.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
In the process of chip transfer, the problem of low chip transfer precision exists. Based on this, the present application intends to provide a solution to the above technical problem, the details of which will be explained in the following embodiments.
Example (b):
the present embodiment provides a chip transfer method, please refer to fig. 1, the chip transfer method includes:
s101, providing a chip carrier plate, wherein a chip is arranged on one side of the chip carrier plate;
s102, forming a temporary bonding structure;
it should be noted that, referring to fig. 2, the temporary bonding structure of the present embodiment includes an adhesive layer 2 disposed on a chip 1, and a through hole 4 disposed on a chip carrier 3, and the adhesive layer 2 is connected to an inner wall of the through hole 4. In some examples, the through hole exposes a portion of a side of the chip close to the chip carrier, and the adhesive layer is disposed in the exposed portion of the chip. It will be appreciated that the adhesive layer has some adhesion, and the connection between the adhesive layer and the chip and the inner wall of the through hole may be achieved by adhesion.
The chip in this embodiment includes but is not limited to an LED light emitting chip or any other chip that needs to be transferred. Illustratively, the LED Light Emitting chip includes, but is not limited to, a Mini-LED (Mini Light-Emitting Diode) chip, a Micro-LED, etc., for example, in one example, the LED chip may be a Mini-LED chip; in yet another example, the LED chip may be a Micro-LED chip.
In the example of fig. 2, the chip 1 comprises epitaxial layers grown on the chip carrier 3, the epitaxial layers comprising a buffer layer 11 and a further epitaxial layer 12, the buffer layer 11 being in contact with the chip carrier 3. When the temporary bonding structure is formed, the buffer layer 11 of the chip 1 corresponding to the through hole 4 is removed, and the bonding layer 2 is disposed on the other epitaxial layer 12 of the chip 1. In this example, the thickness of the adhesive layer 2 is larger than the buffer layer 11 to ensure that the adhesive layer 2 and the through holes 4 on the chip carrier plate 3 can be contacted.
As a specific example, referring to fig. 3, the chip 1 is a Micro-LED chip, the Micro-LED chip is grown on the chip carrier 3, the Micro-LED chip on the chip carrier 3 includes an epitaxial layer and an electrode 13, and the epitaxial layer includes a buffer layer 11 and other epitaxial layers 12 in turn. Illustratively, the other epitaxial layers 12 include, but are not limited to, an N-type semiconductor layer 121, an active layer 122, and a P-type semiconductor layer 123, and the active layer 122 may include a quantum well layer, and may also include other structures. In other examples, the epitaxial layer may further optionally include at least one of a reflective layer and a passivation layer. The material and shape of the electrode 13 are not limited, and for example, the material of the electrode 13 may include, but is not limited to, at least one of Cr, ni, al, ti, au, pt, W, pb, rh, sn, cu, and Ag.
In other examples, as shown in fig. 4, when the temporary bonding structure is formed, the buffer layer 11 of the chip 1 may be entirely remained, and the bonding layer 2 may be disposed on the portion of the buffer layer 11 of the chip 1 corresponding to the via 4. In such an example, the buffer layer 11 remaining on the chip 1 may be removed after the chip 1 is transferred to the target substrate.
S103, removing the buffer layer connected with the chip carrier plate on the chip, and leaving the chip on the chip carrier plate through the bonding layer;
as shown in fig. 5, in the present embodiment, the buffer layer connected to the chip carrier 3 on the chip 1 is removed, and at this time, no other part of the chip 1 except for the adhesive layer 2 is connected to the chip carrier 3. Since the adhesive layer 2 is connected to the inner walls of the through-holes 4, the chip 1 can be left on the chip carrier plate 3 without detaching from the chip carrier plate 3 by the adhesiveness of the adhesive layer 2. As illustrated in fig. 4, after the cushion layer attached to chip carrier 3 on chip 1 is removed, as shown in fig. 6, the portion of cushion layer 11 provided with adhesive layer 2 is not removed temporarily because it is not attached to chip carrier 3, and the rest of cushion layer 11 is removed.
S104, setting the positions of the target substrate and the chip carrier plate so that the side of the chip carrier plate, provided with the chip, is opposite to the side of the target substrate, used for arranging the chip;
for example, referring to fig. 7, the target substrate 5 is disposed opposite to the chip carrier 3. In some examples, the target substrate 5 and the chip carrier 3 may be vertically opposite to each other, and the chip 1 on the chip carrier 3 may fall vertically including gravity after being detached from the chip carrier 3.
S105, removing the connection between the bonding layer arranged on the chip to be transferred and the through hole so as to separate the chip to be transferred from the chip carrier plate;
and the chip falls onto the target carrier plate after being separated from the chip carrier plate, so that the chip is transferred from the chip carrier plate to the target carrier plate.
It is understood that if the adhesive layer and/or the buffer layer remain on the chip after the transfer of the chip is completed, the remaining adhesive layer and/or the buffer layer may be removed in a subsequent process.
In this embodiment, through the temporary bonding structure, an additional bonding layer is disposed between the chip and the chip carrier plate to achieve connection therebetween, and when the chip is transferred, the buffer layer for connecting the chip and the chip carrier plate is removed, so that the chip and the chip carrier plate are bonded only through the bonding layer. Therefore, the method avoids the situation that the chip is impacted by generated gas when the chip is directly stripped by removing the buffer layer, so that the chip is impacted askew, offset and the like, and improves the stability of the chip when the chip is stripped from the chip carrier plate, thereby ensuring the accuracy of chip transfer. Moreover, due to the arrangement of the through holes, even if gas is generated in the process of releasing the connection between the bonding layer and the through holes, the gas is easily discharged along the direction of the through holes, namely, the direction of gas impact can be controlled to a certain extent, and the chips are ensured to stably and accurately fall onto a target carrier plate.
The chip carrier of the present embodiment may be a growth substrate for growing chips. The chip transfer method of the embodiment accurately transfers the chip on the chip carrier to the target substrate. The target substrate may be any substrate that receives a chip, including but not limited to a temporary storage substrate for temporarily holding the chip and a transfer substrate for picking up and transferring the chip, a circuit substrate for setting the chip to realize a corresponding function, and the like.
It is understood that the chip carrier is any material that can be used to grow chips, including but not limited to sapphire, silicon carbide, silicon, gallium arsenide, and other semiconductor materials.
The shape of the through-hole may be arbitrary, and for example, the cross-section of the through-hole may be circular, elliptical, polygonal, or the like. The number of the through holes is not limited for a single chip, and for example, when one through hole is formed corresponding to a single chip, the through hole may be disposed at a central region of the chip. In another example, referring to fig. 8, the chip carrier plate 3 is provided with two through holes 4 in the area corresponding to a single chip 1, the two through holes 4 are symmetrically arranged corresponding to two sides of the chip 1, and the areas of the chip 1 corresponding to the two through holes 4 are respectively provided with the adhesive layers 2.
Referring to fig. 9, in some embodiments, forming a temporary bonding structure includes:
s201, forming through holes in a region where a chip is arranged on a chip carrier plate;
in one example, the through hole extends along the thickness direction of the chip carrier plate, the cross-sectional area of the through hole is smaller than the contact area of the chip and the chip carrier plate, and the through hole exposes a part of the epitaxial layer of the chip.
S202, forming an adhesive layer connected with the inner wall of the through hole on the chip;
that is, in some embodiments, the through-holes are formed first, and then the adhesive layer is disposed.
Referring to fig. 10, in some embodiments, forming a through hole in a region on which a chip is disposed on a chip carrier includes:
s2011, arranging a photoresist layer on one side of the chip carrier plate, which is not provided with the chip;
s2012, patterning the photoresist layer to form a temporary through hole at the position of the photoresist layer corresponding to the chip;
referring to fig. 11, the photoresist layer 6 is exposed using a reticle 7, in this example, the photoresist layer 6 is selected to be a positive photoresist, it being understood that in other examples, a negative photoresist may be selected. As shown in fig. 12, the photoresist layer 6 after exposure is developed, and a temporary via hole 61 is formed on the photoresist layer 6.
S2013, etching the chip carrier plate by using the photoresist layer as a mask plate to remove the region of the chip carrier plate corresponding to the temporary through hole to form a through hole;
as shown in fig. 13, a portion of the chip carrier plate 3 is removed to form a through hole 4. For example, the Etching on the chip carrier plate may adopt, but is not limited to, dry Etching, such as Reactive Ion Etching (RIE), inductively Coupled Plasma (ICP) Etching.
Referring to fig. 14, in some embodiments, forming an adhesive layer on the chip to be connected to an inner wall of the through-hole includes:
s2021, removing the buffer layer on the chip corresponding to the through hole;
as shown in fig. 15, in this step, only the buffer layer 11 of the chip 1 in the region corresponding to the through hole 4 is removed, while the buffer layer 11 on the chip 1 connected to the chip carrier 3 still remains, and at this time, the chip 1 is connected to the chip carrier 3 through the remaining buffer layer 11, so as to ensure that the chip 1 does not detach from the chip carrier 3. In this process, the buffer layer may be removed by means including, but not limited to, laser or etching.
In one example, the photoresist layer as a mask disposed when the through-hole is formed as in fig. 15 is temporarily left after the through-hole is formed, and when the buffer layer is removed in this step S2021, the above-mentioned photoresist layer is also used as a mask to selectively remove only the buffer layer in the region corresponding to the through-hole. After the photoresist layer is utilized, it may be removed.
S2022, arranging an adhesive layer in an area, corresponding to the through hole, of the chip;
referring to fig. 16, since the buffer layer has a certain thickness, the adhesive layer provided in this example is higher than the thickness of the buffer layer, thereby being connected to the inner wall of the via hole.
In this embodiment, the adhesive layer may be a material that can release its adhesiveness under a certain condition or can be decomposed under a certain condition. The adhesive layer can be released from the connection with the through-hole by releasing the adhesiveness of the adhesive layer or decomposing it.
For example, in some embodiments, the adhesive layer decomposes upon irradiation with a laser light of a predetermined wavelength band. The removing of the buffer layer connected to the chip carrier on the chip may include: the buffer layer is irradiated with laser light outside a predetermined wavelength band to decompose the buffer layer, that is, the adhesive layer is not affected when the buffer layer is decomposed. And the connection between the bonding layer arranged on the chip to be transferred and the through hole is released, and the method comprises the following steps: the adhesive layer is irradiated with laser light of a predetermined wavelength band to decompose the adhesive layer. For example, referring to fig. 17, laser light outside a predetermined wavelength band is irradiated to the buffer layer through the side of the chip carrier plate where no chip is disposed, and after the buffer layer is decomposed, the chip is connected to the chip carrier plate only through the adhesive layer. In this embodiment, the adhesive layer is decomposed into gas, and it can be understood that a part of the gas generated by the decomposition of the adhesive layer can be discharged through the through-holes, so that the impact on the chip is reduced and the direction of gas discharge is controlled by the through-holes. In some implementation processes, the through holes are opposite to the target carrier plate, so that the gas decomposed by the bonding layer can generate acting force towards the target carrier plate on the chip, the impact direction of the acting force is accurate, and the chip can be ensured to accurately fall onto the target carrier plate and be separated from the chip carrier plate conveniently through the matching of the through holes and the bonding layer.
As a specific example, the adhesive layer includes, but is not limited to, a glue material of Polymethyl Methacrylate (PMMA), polyimide (PI), and other polymers, and such an adhesive layer may be disposed through a process including, but not limited to, spin coating, spray coating, and the like. For the adhesive layer formed of such a polymer, the predetermined wavelength band of the laser may include the wavelength bands of 355nm,532nm,1064nm, etc., which are also distinguished from the wavelength band of the laser generally used in decomposing the buffer layer.
For example, the buffer layer may be made of gallium nitride (GaN), which may be decomposed into nitrogen and metal gallium at a certain temperature, and in practical applications, the gallium nitride may be irradiated by laser light of certain wavelength bands so that the gallium nitride absorbs photon energy to generate heat, and the temperature is raised to a predetermined temperature to decompose the gallium nitride. In this embodiment, the buffer layer made of gallium nitride may be irradiated with laser light having a wavelength other than the predetermined wavelength band and capable of decomposing gallium nitride, for example, laser light having a wavelength of 248nm, which is different from the predetermined wavelength band for decomposing the adhesive layer, and in other examples, other wavelength bands different from the predetermined wavelength band for decomposing the adhesive layer may be selected.
In some embodiments, before the temporary bonding structure is formed, the chip carrier is thinned to reduce the thickness of the chip carrier. The formation of the temporary bonding structure requires a structure of forming through holes on the chip carrier, which is equivalent to removing a part of material on the chip carrier, and the adoption of a thinner chip carrier facilitates the formation of the temporary bonding structure.
In order to further ensure the accuracy of the chip in the transferring process, the distance between the target substrate and the chip carrier plate may be adjusted, and in some embodiments, the closer distance between the target substrate and the chip carrier plate may reduce the possible offset of the chip to some extent. Thus, in some examples, step S103 above: setting the positions of the target substrate and the chip carrier plate, further comprising:
and S1031, enabling the distance between the chip on the chip carrier board and the target substrate to be smaller than the length of the chip.
As shown in fig. 18, the distance between the chip 1 on the chip carrier plate 3 and the target substrate 5 is selected according to the length of the formed chip. It should be noted that, in the present embodiment, the length of the chip is the length of the longer side, in this example, the length of the chip is h1, and when the positions of the target substrate 5 and the chip carrier 3 are set, the distance between the chip 1 and the target substrate 5 is h2, where h1 is greater than h2.
In some embodiments, the target substrate is provided with a die bond region; positioning the target substrate and the chip carrier further includes aligning electrodes of the chip on the chip carrier with bonding regions of the die attach region, which include, but are not limited to, a region of a bonding pad. In these embodiments, the target substrate may be various circuit substrates, such as a driving back plate of a light emitting chip, and the like. After the chip to be transferred falls on the target substrate, the method further comprises: and bonding the chip falling to the target substrate with the target substrate. In an example, as shown in fig. 19, the target substrate is a circuit substrate 51 provided with a bonding pad, a driving circuit may be disposed on the circuit substrate 51, the driving control is performed on the chip 1, the electrode 13 of the chip is aligned with the bonding pad 52 of the circuit substrate 51, and the chip is directly transferred from the chip carrier 3 on which the chip is grown to the circuit substrate 51 without an intermediate transfer process, that is, the chip transfer method of this embodiment may achieve direct transfer, and the chip carrier 3 and the circuit substrate 51 do not need to be in contact, which is beneficial to selectively transferring the chip 1. The bonding of the chip 1 to the circuit board 51 includes soldering the electrode 13 of the chip 1 to the pad 52. By directly transferring the chips grown on the chip carrier plate to a target substrate such as a circuit substrate, other intermediate transfer steps are omitted, the transfer frequency is reduced, the influence on the yield of the chips is less, and the accuracy of chip transfer is further ensured by fewer transfer frequencies.
In order to better ensure the precision of the chip transferred to the target substrate, in some embodiments, the target substrate may be provided with a glue layer with certain viscosity, and the chip is adhered to the target substrate by the glue layer with certain viscosity after falling to the target substrate, so that the chip is primarily combined with the target substrate, and the chip is prevented from shifting when falling to the target substrate.
Based on the target substrate with the die attach area in the foregoing example, the chip to be transferred is separated from the chip carrier and falls to the target substrate, and the method further includes: arranging an anisotropic conductive adhesive layer on one side of the target substrate, which is provided with the die bonding area;
bonding a chip to a target substrate, comprising: the chip adhered to the anisotropic conductive adhesive layer is electrically connected with the anisotropic conductive adhesive layer, and the anisotropic conductive adhesive layer limits the current to flow in the thickness direction of the anisotropic conductive adhesive layer.
Illustratively, referring to fig. 20, the target substrate 5 is provided with a pad 52, and the pad 52 is used as a bonding region for electrically connecting with the chip 1. Before detaching the chip 1 from the chip carrier 3, an anisotropic conductive adhesive layer 53 is coated on the surface of the target substrate 5 provided with the bonding pads 52, wherein the thickness of the anisotropic conductive adhesive layer 53 is greater than the height of the bonding pads 52, that is, the anisotropic conductive adhesive layer 53 completely covers the bonding pads 52. When the positions of the target substrate 5 and the chip carrier 3 are set, the electrode of the chip 1 on the chip carrier 3 is aligned with the pad 52 of the target substrate, and after the chip 1 falls to the target substrate 5, the electrode of the chip 1 is not directly contacted with the pad 52, but is bonded with the anisotropic conductive adhesive layer 53, but the electrode of the chip 1 is opposite to the pad 52, and the anisotropic conductive adhesive layer 53 conducts current in the thickness direction, so that the electrode of the chip 1 can be electrically connected with the pad 52.
Through setting up the anisotropic conductive adhesive layer for the chip can be tentatively bonded to the target base plate when falling to the target base plate, and can directly utilize this anisotropic conductive adhesive layer to realize the bonding of chip and target base plate.
Of course, in other examples, for example, the target substrate is a temporary substrate, only the chip needs to be temporarily stored, and the die attach region is not provided, so that the primary bonding of the chip can be realized by using a common adhesive layer.
In practical applications, the chip transferring method of the embodiment may be non-selective transferring or selective transferring, that is, all chips on the chip carrier may be transferred, or part of chips on the chip carrier may be selectively transferred. It will be appreciated that selective transfer can be achieved by selectively disconnecting the adhesive layer from the via. For example, the adhesive layer of a part of the chips to be transferred is selectively irradiated by laser with a predetermined waveband, so that only the part of the chips to be transferred is separated from the chip carrier plate, and the selective transfer can be realized.
The present embodiment further provides a display panel, where the display panel includes a light emitting chip and a circuit substrate, and the light emitting chip is transferred to a die attach area of the circuit substrate by the above-mentioned chip transfer method of the present embodiment. The display panel of the embodiment has the advantages that the setting precision of the light emitting chip is high, and the quality is good. In some implementation processes, the light-emitting chips of the display panel can be directly transferred to the circuit substrate from the growth substrate, the transfer times are few, the influence on the yield of the light-emitting chips is low, and meanwhile, the transfer times are fewer, and the accuracy of chip transfer is also guaranteed.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.
Claims (10)
1. A method of chip transfer, comprising:
providing a chip carrier plate, wherein a chip is arranged on one side of the chip carrier plate;
forming a temporary bonding structure, wherein the temporary bonding structure comprises a bonding layer arranged on the chip and a through hole arranged on the chip carrier plate, and the bonding layer is connected with the inner wall of the through hole;
removing the buffer layer connected with the chip carrier plate on the chip, wherein the chip is left on the chip carrier plate by the bonding layer;
setting positions of a target substrate and the chip carrier plate so that one side of the chip carrier plate, which is provided with the chip, is opposite to one side of the target substrate, which is used for arranging the chip;
and the bonding layer arranged on the chip to be transferred is disconnected from the through hole, so that the chip to be transferred is separated from the chip carrier plate and falls to the target substrate.
2. The chip transfer method according to claim 1, wherein said forming a temporary bonding structure comprises:
forming the through hole in the area of the chip on the chip carrier plate;
and forming the bonding layer connected with the inner wall of the through hole on the chip.
3. The chip transfer method according to claim 2, wherein the forming the through holes in the area of the chip carrier where the chip is disposed comprises:
arranging a photoresist layer on one side of the chip carrier plate, which is not provided with the chip;
patterning the photoresist layer to form a temporary through hole at a position of the photoresist layer corresponding to the chip;
and etching the chip carrier plate by using the photoresist layer as a mask plate, so that the region of the chip carrier plate corresponding to the temporary through hole is removed to form the through hole.
4. The chip transfer method according to claim 2, wherein the forming of the adhesive layer on the chip in connection with the inner wall of the through-hole comprises:
removing the buffer layer of the chip in the region corresponding to the through hole;
and arranging the bonding layer in the area of the chip corresponding to the through hole.
5. The chip transfer method according to claim 1, wherein the adhesive layer is irradiated with a laser of a predetermined wavelength band to decompose a gas;
the removing the buffer layer connected with the chip carrier plate on the chip comprises the following steps:
irradiating the buffer layer with laser light outside the predetermined wavelength band to decompose the buffer layer;
the making the bonding layer arranged on the chip to be transferred remove the connection with the through hole comprises the following steps:
and irradiating the bonding layer by using the laser with the preset wave band so as to decompose the bonding layer.
6. The chip transfer method according to claim 1, wherein the setting of the positions of the target substrate and the chip carrier further comprises:
and enabling the distance between the chip on the chip carrier plate and the target substrate to be smaller than the length of the chip.
7. The chip transfer method according to any one of claims 1 to 6, wherein the target substrate is provided with a die attach region;
the setting of the positions of the target substrate and the chip carrier plate further comprises:
aligning the electrode of the chip on the chip carrier plate with the bonding area of the die bonding area;
after the chip to be transferred falls to the target substrate, the method further includes:
bonding the chip dropped to the target substrate with the target substrate.
8. The chip transfer method according to claim 7, wherein the chip to be transferred is detached from the chip carrier and falls to the target substrate, further comprising:
arranging an anisotropic conductive adhesive layer on one side of the target substrate, which is provided with the die bonding area;
the bonding the chip with the target substrate includes:
and electrically connecting the chip adhered to the anisotropic conductive adhesive layer with the anisotropic conductive adhesive layer, wherein the anisotropic conductive adhesive layer limits the current to flow in the thickness direction of the anisotropic conductive adhesive layer.
9. The chip transfer method according to any one of claims 1 to 6, wherein before the forming of the temporary bonding structure, further comprising:
and thinning the chip carrier plate to reduce the thickness of the chip carrier plate.
10. A display panel comprising a light emitting chip and a circuit substrate, wherein the light emitting chip is transferred to a die attach region of the circuit substrate by the chip transfer method according to any one of claims 1 to 9.
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| CN202111085359.XA CN115832117A (en) | 2021-09-16 | 2021-09-16 | Chip transfer method and display panel |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116682912A (en) * | 2023-06-21 | 2023-09-01 | 惠科股份有限公司 | Light emitting chip, display panel, light emitting assembly and manufacturing method thereof |
| CN116682901A (en) * | 2023-06-21 | 2023-09-01 | 惠科股份有限公司 | Light emitting component, manufacturing method of light emitting component, light emitting chip and display panel |
| CN118404905A (en) * | 2024-07-04 | 2024-07-30 | 绍兴圆炬科技有限公司 | Laser equipment for chip transfer printing and control method thereof |
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2021
- 2021-09-16 CN CN202111085359.XA patent/CN115832117A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116682912A (en) * | 2023-06-21 | 2023-09-01 | 惠科股份有限公司 | Light emitting chip, display panel, light emitting assembly and manufacturing method thereof |
| CN116682901A (en) * | 2023-06-21 | 2023-09-01 | 惠科股份有限公司 | Light emitting component, manufacturing method of light emitting component, light emitting chip and display panel |
| CN116682912B (en) * | 2023-06-21 | 2024-05-28 | 惠科股份有限公司 | Light emitting chip, display panel, light emitting assembly and manufacturing method thereof |
| CN118404905A (en) * | 2024-07-04 | 2024-07-30 | 绍兴圆炬科技有限公司 | Laser equipment for chip transfer printing and control method thereof |
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