CN215238543U - Laser stripping off device - Google Patents

Abstract

The utility model discloses a laser stripping device for the huge transfer of chip, wherein, the laser stripping device includes laser instrument, light beam integer subassembly and light beam transmission subassembly, the light beam integer subassembly is located one side of laser instrument light-emitting, is used for becoming the laser beam of uniform distribution's laser beam shaping quadrangle cross section with the laser beam that the laser instrument jetted out; the light beam transmission assembly is arranged on the light emitting side of the light beam shaping assembly and used for transmitting the laser light beam with the quadrangular cross section transmitted by the light beam shaping assembly to the chip to be transferred. At the in-process that shifts the chip, laser can make and wait to shift the chip and peel off with native base plate, conveniently carries out the chip and shifts, and after laser beam's cross section was become the quadrangle by even integer, the energy distribution of scanning facula was more even, and the energy at facula edge is strengthened, is convenient for peel off the chip at scanning region edge.

Description

Laser stripping off device

Technical Field

The utility model relates to a show technical field, especially relate to a laser stripping off device.

Background

Currently, in the manufacturing process of Micro LED display screens, a bulk transfer technology is used to selectively transfer Light Emitting Diode (LED) chips from a native substrate to a backplane printed with an integrated circuit to complete bonding. In the bulk transfer process, the primary substrate is scanned with a pulsed laser beam to peel the chip off the primary substrate.

However, since the spots formed by the laser beams emitted by the conventional laser emitters are all circular or elliptical, and the energy of the spots is gaussian distributed, the energy of the middle area is large, and the energy of the edge area is small, when the original substrate is selectively scanned, the edge position of the scanning area is irradiated only by the edge part of the spot, and thus the original substrate cannot be smoothly peeled off due to insufficient energy.

Accordingly, the prior art is yet to be improved and developed.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned deficiencies of the prior art, an object of the present invention is to provide a laser lift-off device, which aims to solve the problem that the edge of the scanning area is not sufficiently irradiated and cannot be smoothly lifted off.

The technical scheme of the utility model as follows:

a laser stripping device is used for transferring a large amount of chips, and comprises a laser, a beam shaping assembly and a beam transmission assembly, wherein the beam shaping assembly is arranged on the light emitting side of the laser and is used for shaping laser beams emitted by the laser into laser beams with uniformly distributed quadrangular cross sections; the light beam transmission assembly is arranged on the light emitting side of the light beam shaping assembly and used for transmitting the laser light beam with the quadrangular cross section transmitted by the light beam shaping assembly to the chip to be transferred.

Optionally, the beam shaping assembly includes a coupling optical element and a homogenizing fiber, the coupling optical element is located on an outgoing light path of the laser, and the coupling optical element is configured to couple a laser beam emitted by the laser into the homogenizing fiber; the homogenizing optical fiber is positioned on the light-emitting path of the coupling optical element, and the light beam transmission assembly is arranged on the light-emitting path of the homogenizing optical fiber and is used for shaping the laser light beam emitted from the coupling optical element.

Optionally, the homogenizing optical fiber comprises a fiber core and a protective sleeve, and the cross section of the fiber core is quadrilateral; the protective sleeve is coated outside the fiber core.

Optionally, the protective jacket includes a first cladding and a second cladding, the first cladding is coated outside the core, and an outer sidewall of the first cladding is cylindrical; the second cladding is coated outside the first cladding.

Optionally, the refractive index of the core is greater than the refractive index of the first cladding and the refractive index of the second cladding, and the refractive index of the first cladding is greater than the refractive index of the second cladding.

Optionally, the fiber core is a silica fiber core, and the first cladding and the second cladding are silica glass layers.

Optionally, the coupling optical element is a convex lens, a concave lens, a cylindrical mirror, an aspherical mirror, or a lens group.

Optionally, the light beam transmission assembly includes a collimating lens, a laser galvanometer and a laser field lens, and the collimating lens is located on the light-emitting side of the light beam shaping assembly; the laser galvanometer is used for changing the transmission direction of the laser beam transmitted by the collimating mirror to form a scanning beam; the laser field lens is positioned in the light-emitting direction of the laser galvanometer and used for focusing the scanning light beam formed on the laser galvanometer on a chip to be transferred.

Optionally, the light beam transmission assembly further includes a reflector, and the reflector is located between the collimating mirror and the laser galvanometer and is configured to guide the laser light beam transmitted by the collimating mirror to the laser galvanometer.

Optionally, the reflector is a right triangular prism.

Compared with the prior art, the embodiment of the utility model provides a have following advantage:

the application discloses a laser stripping device is applied to the process of chip mass transfer, a laser generates and emits a laser beam and transmits the laser beam to a beam shaping assembly, the original laser beam is round or oval, the energy is in a Gaussian distribution state, the beam shaping assembly shapes the laser beam into a laser beam with a quadrangular cross section, the Gaussian distribution of the internal energy of the laser beam is damaged, the light is in a chaotic state in the laser beam, the energy of the laser beam can be dispersed to the periphery, the energy distribution of the laser beam at the emitting end of the beam shaping assembly is more uniform, and when the laser beam is transmitted to a primary substrate through a beam transmission assembly, the energy at the middle position is high, the chip to be transferred can be stripped, the energy at the edge position is also high, the chip to be transferred can be stripped sufficiently, and the chip to be transferred can be stripped from the primary substrate smoothly on the whole, is beneficial to improving the efficiency of mass transfer.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is an assembly view of the laser lift-off device of the present invention;

fig. 2 is a schematic diagram of the relative position of the laser spot emitted by the laser lift-off device of the present invention;

fig. 3 is a schematic structural diagram of a cross section of the homogenized optical fiber according to the present invention.

10, a laser; 20. a beam shaping assembly; 21. a coupling optical element; 22. homogenizing the optical fiber; 221. a fiber core; 222. a protective sleeve; 2221. a first cladding layer; 2222. a second cladding layer; 30. a light beam transmission assembly; 31. a collimating mirror; 32. a laser galvanometer; 33. a laser field lens; 34. a mirror.

Detailed Description

In order to make the technical solution of the present invention better understood, the following figures in the embodiments of the present invention are combined to clearly and completely describe the technical solution in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The development of the LED display technology in the prior art is continuously advanced, and the Micro Light Emitting Diode (Micro LED) display technology is a new generation display technology, which has a very wide application prospect, and the Micro LED has a self-luminous display characteristic, and compared with the existing Organic Light-Emitting Diode (OLED) display technology, the Micro LED has the advantages of higher brightness, better Light Emitting efficiency, and lower power consumption.

The Micro LED display technology is a display technology which takes self-luminous micrometer-scale LEDs as light-emitting pixel units and assembles the light-emitting pixel units on a driving panel to form a high-density LED array. The conventional preparation method is not applicable because the Micro LED chip has small size and high integration level, and the conventional preparation method of the Micro LED chip generally comprises the steps of firstly preparing the LED chip on a primary substrate, then selectively and massively picking up the LED chips on the primary substrate by using a massive transfer method, and transferring the LED chips to a back plate, wherein an integrated circuit is printed on the back plate, and the integrated circuit and the LED chip are bonded to obtain the whole Micro LED display module.

Common technologies used in the process of mass transfer at present include laser lift-off, selective laser transfer and the like, wherein Micro LEDs are lifted off from a primary substrate to a transient substrate by laser, then the Micro LEDs on the transient substrate are transferred to an integrated circuit back plate by the selective laser transfer, wherein the cross section of the laser beam is generally circular or elliptical facula, and the energy distribution of the circular or elliptical facula is Gaussian distribution, so that the facula and the facula are necessarily overlapped when the pulse laser scans, therefore, in selective scanning, the Micro LEDs at the edge of the scanning area are not sufficiently stripped due to the low energy of the laser irradiation, in this case the scanning area must be widened outwards if the preset selection area is to be peeled off in its entirety, therefore, the Micro LED which is not to be peeled off originally is damaged or loosened due to the irradiation of laser energy. In summary, the conventional bulk transfer process has low transfer efficiency because the laser irradiation process cannot smoothly and accurately peel off the LED chip at the edge of the preselected area.

Referring to fig. 1, in an embodiment of the present invention, a laser lift-off device is disclosed, which is used for transferring a large amount of chips, wherein the laser lift-off device includes a laser 10, a beam shaping component 20 and a beam transmission component 30, the beam shaping component 20 is disposed on one side of the light emitted from the laser 10, and is used for shaping the laser beam emitted from the laser 10 into a laser beam with a uniformly distributed quadrilateral cross section; the light beam transmission assembly 30 is arranged on the light-emitting side of the light beam shaping assembly 20 and is used for transmitting the laser beam with a quadrangular cross section, which is transmitted by the light beam shaping assembly 20, to a chip to be transferred.

The laser stripping device disclosed by the application is applied to the process of transferring a great amount of chips, a laser 10 generates and emits a laser beam, and the laser beam is transmitted to a beam shaping assembly 20, the original laser beam is circular or elliptical, the energy is in a Gaussian distribution state, the beam shaping assembly 20 shapes the laser beam into a laser beam with a quadrangular cross section, the Gaussian distribution of the internal energy of the laser beam is damaged, the light is in a chaotic state in the laser beam, the energy of the laser beam can be dispersed to the periphery, the energy distribution of the laser beam at the emitting end of the beam shaping assembly 20 is more uniform, and when the laser beam is transmitted to an original substrate through a beam transmission assembly 30, not only is the energy at the middle position high, the chip to be transferred can be stripped, the energy at the edge position is also high, the chip to be transferred can be stripped sufficiently, and the chip to be transferred can be stripped from the original substrate smoothly on the whole, the efficiency of mass transfer is improved; the cross section of the laser beam is shaped into a rectangle or a square, the centrosymmetric shape is still kept, certain symmetric distribution can be kept while the internal energy of the laser beam is disturbed, the situations that one side of the laser beam is strong and the other side of the laser beam is weak are avoided, the laser beam is dispersed to the edge position of a scanning area, the laser energy is kept uniformly distributed, and the situation of local concentration is reduced.

As shown in fig. 1, as an implementation manner in the present embodiment, it is disclosed that the beam shaping component 20 includes a coupling optical element 21 and a homogenizing fiber 22, where the coupling optical element 21 is located on an output light path of the laser 10, and the coupling optical element 21 is used for coupling a laser beam emitted from the laser 10 into the homogenizing fiber 22; the homogenizing optical fiber 22 is located on the light-emitting path of the coupling optical element 21, and the beam transmission assembly 30 is located on the light-emitting path of the homogenizing optical fiber 22 and is configured to shape the laser beam emitted from the coupling optical element 21. Because the light emitted by the laser 10 is generally scattered and the cross-sectional area of the optical fiber is small, the coupling optical element 21 is arranged to collect and gather the light emitted by the laser 10 on the homogenizing optical fiber 22, increase the energy of the laser beam entering the homogenizing optical fiber 22, enable the laser beam emitted after the homogenizing optical fiber 22 is shaped to have enough energy to be transmitted to the original substrate and can strip the chip to be transferred, and the laser beam emitted to the homogenizing optical fiber 22 is shaped to form a quadrangle from the original circle or ellipse; as shown in fig. 2, because the bulk transfer is performed by scanning the original substrate with the pulsed laser, rather than continuous scanning, a displacement difference exists between light spots generated by two adjacent scans, and a circular or elliptical light spot generated by the original laser beam is arc-shaped at any position of the edge portion, so that an unscanned blind area always forms between two adjacent light spots, and a chip to be transferred located in the scanning blind area is difficult to transfer from the original substrate to the transient substrate due to insufficient laser energy during transfer, and thus the efficiency and accuracy of the bulk transfer are affected; as shown in fig. 2 a; however, the cross section of the shaped laser beam is quadrilateral, and as shown in a diagram b in fig. 2, four sides of the quadrilateral are all straight lines, so that the shaped laser beam pulses irradiate on the original substrate, adjacent light spots are overlapped with each other, and a blind area is not generated, thereby being beneficial to stripping off a chip to be transferred at the edge position of a scanning area and realizing accurate and efficient chip transfer.

Specifically, as another implementation manner in this embodiment, it is disclosed that the coupling optical element 21 is a convex lens, a concave lens, a cylindrical lens, an aspherical mirror, or a lens group. As shown in fig. 1, the coupling optical element 21 may be disposed to face the laser 10, and the convex surface faces the convex lens of the homogenizing fiber 22, so as to focus the laser beam, and correspondingly, a special optical element such as a concave lens, a cylindrical lens or an aspherical lens may be used to focus the laser beam on the homogenizing fiber 22 in a specific manner, or even a lens group combining a plurality of lenses may be used.

Referring to fig. 3, as another implementation manner in the present embodiment, it is disclosed that the homogenizing fiber 22 includes a fiber core 221 and a protective sheath 222, and the cross-sectional shape of the fiber core 221 is a quadrangle; the protective jacket 222 covers the core 221. Because the fiber core 221 is generally made of glass material and is relatively fragile, the protective sleeve 222 is used for wrapping the outer side of the fiber core 221 to protect the fiber core 221, so that the fiber core 221 is prevented from being collided and abraded in the using process, and the fiber core 221 is prevented from being damaged; the fiber core 221 mainly plays a role in shaping the laser beam, after the laser beam on the coupling optical element 21 is coupled to the homogenizing fiber 22, the laser beam is transmitted along the fiber core 221, because the cross section of the fiber core 221 is quadrilateral, the laser beam can only be transmitted on the fiber core 221 with a quadrilateral cross section, because the initial energy distribution of the laser beam is strong in the middle, weak in the edge and gaussian-shaped, while in the fiber core 221 disclosed in this embodiment, because the quadrilateral has four sides and is not a structure which is completely symmetrical at any angle like a circle, the position from the edge to the center of the quadrilateral is far and near, the energy of the laser beam can not maintain the most stable gaussian distribution, more high-order modes are excited, further the energy is dispersed to the edge position, the energy of the laser beam is distributed more uniformly on the same cross section as a whole, so that when the laser beam peels off the chip to be transferred, the laser intensity of the chip to be transferred on the edge of the scanning area is further increased, and the chip to be transferred on the edge is further smoothly peeled. Certainly, in order to smoothly peel off the chip to be transferred at the edge position of the scanning area, the intensity of the laser beam can be increased to increase the energy irradiated on the chip to be transferred, but the energy at the center position of the laser beam is possibly too high to easily damage the original substrate, and the laser beam is shaped into a quadrangle, so that the energy at the middle position of the laser beam can be dispersed, the original substrate is protected, and the damage of the laser beam to the original substrate is reduced.

As shown in fig. 3, as another implementation manner in this embodiment, it is disclosed that the protection casing 222 includes a first cladding 2221 and a second cladding 2222, the first cladding 2221 is cladded outside the core 221, and the outer sidewall of the first cladding 2221 is cylindrical in shape; the second cladding layer 2222 is coated outside the first cladding layer 2221. Because the cross-sectional shape of the fiber core 221 is quadrilateral, the outer side wall of the fiber core 221 is a prismatic side wall, has corners, is not round and is easy to damage, the first cladding 2221 is arranged to wrap the outer side of the fiber core 221 into a cylindrical shape, the fiber core 221 is wrapped in the cylindrical shape for protection, and the shape of the outer wall is modified, so that the second cladding 2222 with the same thickness can be formed in each direction during secondary wrapping, the second cladding 2222 is also cylindrical, the outer surface of the homogenized optical fiber 22 has no corners, collision damage in the transportation process can be reduced, the homogenized optical fiber 22 can be placed at any angle, and transportation and use are facilitated.

Specifically, as another implementation manner in this embodiment, it is disclosed that the refractive index of the core 221 is greater than the refractive index of the first cladding 2221 and the refractive index of the second cladding 2222, and the refractive index of the first cladding 2221 is greater than the refractive index of the second cladding 2222. Because the laser beam needs to be kept in the fiber core 221 in the process of shaping the laser beam, and the cross section of the fiber core 221 in the embodiment is quadrilateral, which causes the energy of the laser beam to be in a chaotic state when the laser beam is transmitted in the fiber core 221 and to be dispersed all around, in order to prevent the laser beam from passing through the first cladding 2221 and even escaping from the second cladding 2222, the refractive index of the fiber core 221 is set to be maximum, so that the laser beam can be transmitted only in the fiber core 221; further, the refractive index of the first cladding 2221 is set to be larger than that of the second cladding 2222, and thus, even if the laser beam escapes into the first cladding 2221, the laser beam can be blocked again by the second cladding 2222, and the laser beam can be prevented from being emitted.

Specifically, as another implementation manner in this embodiment, it is disclosed that the core 221 is a silica core 221, and the first cladding 2221 and the second cladding 2222 are both silica glass layers. The core 221, the first cladding 2221, and the second cladding 2222 can all be manufactured using quartz as a raw material, which is advantageous in reducing the kinds of raw materials and saving costs. In addition, in another implementation manner of this embodiment, the core 221 may also be a quartz core 221, and the first cladding 2221 and the second cladding 2222 may also be light-tight rubber layers, plastic layers, or the like, so as to increase the buffering performance and the protection performance of the protective sleeve 222, and enhance the protection to prevent light leakage.

Referring to fig. 1, as another implementation manner in this embodiment, it is disclosed that the light beam transmission assembly 30 includes a collimating lens 31, a laser galvanometer 32, and a laser field lens 33, where the collimating lens 31 is located on a light-emitting side of the light beam shaping assembly 20; the laser galvanometer 32 is used for changing the transmission direction of the laser beam transmitted by the collimating mirror 31 to form a scanning beam; the laser field lens 33 is located in the light emitting direction of the laser galvanometer 32, and the laser field lens 33 is used for focusing the scanning beam formed on the laser galvanometer 32 on a chip to be transferred. Since the cross-sectional area of the homogenizing fiber 22 is small, the emitted laser beam is shaped into a laser beam with a quadrangular cross section, but the irradiation range is too small and is diffused, and the original substrate needs to be adjusted into a pulse laser for scanning; through setting up collimating mirror 31 in homogenization optical fiber 22's light-emitting one side and carrying out refraction adjustment to laser, make laser beam not only the irradiation range grow, the direction of illumination becomes perpendicular incidence moreover, no longer diverges, and then sets up laser galvanometer 32 and form scanning beam, and rethread laser field mirror 33 focuses on scanning beam to predetermined position, carries out accurate laser scanning to primary base plate to realize that laser peels off. The beam transmission assembly 30 is arranged to adjust the shaped laser beam into usable, efficient and accurate scanning pulse laser, thereby promoting the realization of the laser lift-off process.

As shown in fig. 1, as another implementation manner in this embodiment, it is disclosed that the light beam transmission assembly 30 further includes a reflecting mirror 34, where the reflecting mirror 34 is located between the collimating mirror 31 and the laser galvanometer 32, and is used for guiding the laser light beam transmitted by the collimating mirror 31 to the laser galvanometer 32. Since the design of the production line is affected by the field during the actual production process, sometimes because the space occupied by the laser 10, the beam shaping assembly 20, and the beam transmission assembly 30 is too large, if all the optical elements are arranged in the same direction, the requirement on the field is too high, so that a reflector 34 can be arranged during the transmission process, and the transmission direction of the laser beam can be adjusted by the reflector 34, so as to guide the laser beam to the laser oscillating mirror 32 which is not in the same straight line with the position of the collimating mirror 31, in an implementation manner of the embodiment, the reflector 34 is a right-angled prism. The laser beam is reflected by the inclined surface of the prism, so that the laser can change the transmission direction.

To sum up, the utility model discloses a laser stripping off device for the huge transfer of chip, laser stripping off device includes laser instrument 10, beam shaping subassembly 20 and beam transmission subassembly 30, beam shaping subassembly 20 locates the one side that laser instrument 10 goes out light, is used for shaping the laser beam that laser instrument 10 jetted out into the laser beam that the cross section that evenly distributes is the quadrangle; the light beam transmission assembly 30 is arranged on the light-emitting side of the light beam shaping assembly 20 and used for transmitting the laser light beam with a quadrangular cross section, which is transmitted by the light beam shaping assembly 20, to the chip. In the transferring process of the chip to be transferred, the chip to be transferred can be peeled off from the original substrate by the pulse laser, so that the chip is transferred, after the cross section of the laser beam is shaped into a quadrilateral by the beam shaping assembly 20, the energy distribution of the laser beam is more uniform, the energy of the edge position is enhanced, the laser beam is adjusted to be scanned by the beam transmission assembly 30 and then irradiated onto the original substrate, and the chips to be transferred at all positions in the scanning area are effectively peeled off.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims (10)

1. A laser lift-off device for bulk transfer of chips, the laser lift-off device comprising:

a laser;

the beam shaping assembly is arranged on the light emitting side of the laser and is used for shaping the laser beam emitted by the laser into laser beams which are uniformly distributed and have quadrangular cross sections; and

and the beam transmission assembly is arranged on the light-emitting side of the beam shaping assembly and is used for transmitting the laser beam with the quadrangular cross section transmitted by the beam shaping assembly to the chip to be transferred.

2. The laser lift off device of claim 1 wherein the beam shaping assembly comprises: a coupling optical element and a homogenizing fiber;

the coupling optical element is positioned on a light-emitting path of the laser, and is used for coupling a laser beam emitted by the laser into the homogenizing optical fiber;

the homogenizing optical fiber is positioned on the light-emitting path of the coupling optical element, and the light beam transmission assembly is arranged on the light-emitting path of the homogenizing optical fiber and is used for shaping the laser light beam emitted from the coupling optical element.

3. The laser lift off device of claim 2, wherein the homogenizing fiber comprises:

the fiber core is quadrangular in cross section;

and the protective sleeve is coated outside the fiber core.

4. The laser lift off device of claim 3, wherein the protective jacket comprises a first cladding and a second cladding, the first cladding is clad outside the core, and an outer sidewall of the first cladding is cylindrical in shape; the second cladding is coated outside the first cladding.

5. The laser lift off device of claim 4, wherein the refractive index of the core is greater than the refractive index of the first cladding and the refractive index of the second cladding, and the refractive index of the first cladding is greater than the refractive index of the second cladding.

6. The laser lift off device of claim 4 wherein the core is a silica core and the first cladding and the second cladding are silica glass layers.

7. The laser lift off device of claim 2, wherein the coupling optics are a convex lens, a concave lens, a cylindrical mirror, an aspherical mirror, or a lens group.

8. The laser lift off device of claim 1, wherein the beam delivery assembly comprises:

the collimating lens is positioned on the light-emitting side of the light beam shaping component;

the laser galvanometer is used for changing the transmission direction of the laser beam transmitted by the collimating mirror to form a scanning beam; and

and the laser field lens is positioned in the light emergent direction of the laser galvanometer and used for focusing the scanning beam formed on the laser galvanometer on the chip to be transferred.

9. The laser lift off device of claim 8, wherein the beam delivery assembly further comprises a mirror positioned between the collimating mirror and the laser galvanometer for directing the laser beam delivered by the collimating mirror onto the laser galvanometer.

10. The laser lift off device of claim 9 wherein the mirror is a right triangular prism.

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