JP7443041B2 - Optical spot image irradiation device and transfer device - Google Patents

Description

The present invention provides light spot image irradiation in which a light ray emitted from a single light source is divided into a plurality of light rays, and a light spot image consisting of a plurality of light spots is irradiated onto a surface to be irradiated by the plurality of light rays. Regarding equipment.

Furthermore, the present invention relates to a chip transfer device that uses the light spot image to transfer a chip placed on a flat substrate onto a transfer surface.

In recent years, semiconductor chips have been miniaturized to reduce costs, and efforts are being made to mount these miniaturized semiconductor chips with high precision. In particular, for LEDs used in displays, it is required that semiconductor chips, called micro-LEDs, measuring 50 um x 50 um or less be mounted at high speed with an accuracy of several um.

When mounting these minute semiconductor chips at high speed, the semiconductor chip is peeled off from the carrier substrate by irradiating a laser beam onto the bonding surface of the semiconductor chip bonded to the carrier substrate, and is biased and transferred to the transfer substrate. A so-called laser lift-off method is used. However, this laser lift-off is also required to be faster, and for example, if a plurality of semiconductor chips can be transferred simultaneously by one laser irradiation, this can contribute to faster laser lift-off.

A method for simultaneously transferring multiple semiconductor chips is to irradiate the carrier substrate with a line-shaped laser and peel off the semiconductor chips arranged in a row on the carrier substrate at the same time, and to split the laser light emitted from one laser light source. A possible method is to simultaneously irradiate the bonding surfaces of multiple semiconductor chips and peel them off from the carrier substrate. Among these, as a technique for branching a laser beam emitted from one laser light source, Patent Document 1 discloses that a single laser beam is incident on an acousto-optic element to which RF power is applied, and a laser beam is generated by Ramannus diffraction. A laser processing apparatus is shown in which a laser beam is split into a plurality of beams, and the beams are transmitted through a condensing lens and irradiated onto the surface of a workpiece to perform line-shaped processing.

Japanese Patent Application Publication No. 2009-248173

However, in the laser processing apparatus of Patent Document 1, there is a possibility that a difference occurs in the power of the plurality of beams, resulting in unstable chip transfer. Specifically, since the intensity of light diffracted by an acousto-optic element follows a Bessel function, the power of the zero-order light is the strongest, and the more the light is diffracted, the weaker the power becomes, so the power of the multiple beams that are split There was a problem that there was a difference in the

In view of the above problems, the present invention provides a light spot image irradiation device that divides a light beam and irradiates a light spot image consisting of a light spot with uniform power onto a surface to be irradiated, and a chip transfer device using the same. The purpose is to provide

In order to solve the above problems, a light spot image irradiation device of the present invention is a light spot image irradiation device that irradiates a light spot image consisting of a plurality of light spots onto a surface to be irradiated, and includes a laser light source and a laser light source. The laser beam is characterized by having a phase diffraction element that splits a laser beam emitted from the laser beam into a plurality of light beams, and a variable focus optical system provided between the phase diffraction element and the irradiated surface.

With this light spot image irradiation device, it is possible to branch a light beam and irradiate a light spot image with uniform power to any plurality of positions in the in-plane direction of the irradiated surface. Specifically, by splitting one light beam into multiple light beams using a phase diffraction grating, it is possible to form a light spot image with equal power for each light beam, and by having a variable focus optical system, , it is possible to irradiate a light spot image at an arbitrary pitch.

Further, it is preferable to further include a light spot image shifting means for shifting the light spot image formed by the plurality of light beams in an in-plane direction of the irradiated surface.

By doing so, it is possible to successively irradiate the irradiated object with more light spot images than the number of light spot images to be irradiated by one laser beam emission.

Further, an imaging optical system is further provided between the variable focus optical system and the irradiated surface for forming an image formed by the variable focus optical system on the irradiated surface, and in the imaging optical system. Preferably, there is a galvanometer mirror optical system as the light spot image shifting means.

By doing so, the position where the light spot image is irradiated can be arbitrarily adjusted.

Further, it is preferable that the light spot image shifting means include a moving stage that moves the irradiated surface itself.

By doing so, the position where the light spot image is irradiated can be arbitrarily adjusted.

Moreover, in order to solve the above-mentioned problem, the transfer device of the present invention provides a transfer device according to any one of claims 1 to 4 for a chip located at an arbitrary position among a plurality of chip groups arranged in a matrix on a flat base material. The present invention is characterized in that the chip is transferred to a transfer surface by irradiating a light spot image generated by the light spot image irradiation device described in the above.

With this transfer device, it is possible to branch a light beam and irradiate a plurality of arbitrary chips in a two-dimensional direction among a group of chips with a light beam of uniform power, and it is possible to accurately transfer each chip. Specifically, by splitting a single light beam into multiple light beams using a phase diffraction grating, it is possible to form a light spot image in which the power of each light beam is equal. By having this, it is possible to simultaneously irradiate a plurality of chips arranged at an arbitrary pitch with a light spot image.

With the light spot image irradiation device and transfer device of the present invention, a light beam can be divided and a light spot image consisting of light spots having uniform power can be irradiated onto a surface to be irradiated.

FIG. 1 is a diagram illustrating a light spot image irradiation device in an embodiment of the present invention. It is a figure explaining the form of the light beam on the real image plane in the optical spot image irradiation device of this embodiment. FIG. 2 is a diagram illustrating a process in which chips are sequentially transferred by a chip transfer device using a light spot image irradiation device of the present invention. FIG. 3 is a diagram illustrating a process in which a light spot image is sequentially irradiated onto a surface to be irradiated by the light spot image irradiation device of the present embodiment. It is a figure explaining the optical spot image irradiation device in other embodiments of this invention.

A light spot image irradiation device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1(a) is a side view of the optical spot image irradiation device 1, and FIG. 1(b) is a top view of the optical spot image irradiation device 1.

The light beam device 1 of this embodiment branches a light beam and irradiates a light spot image consisting of a light spot to arbitrary plural positions in the in-plane direction of the irradiated surface, and includes a laser light source 11, a beam expander 12, It has a phase diffraction element 13, a zoom lens 14, a collimating lens 15, a galvano mirror 16, and an Fθ lens 17, and the laser beam B emitted from the laser light source 11 is transmitted to a beam expander 12, a phase diffraction element 13, and a zoom lens 14. , the collimating lens 15, the galvanometer mirror 16, and the Fθ lens 17 in this order to reach the irradiated surface S. During this time, one laser beam B is branched by the phase diffraction element 13 into a plurality of light beams B1.

In this description, the vertical direction will be referred to as the Z-axis direction, the horizontal direction in which the light beam is emitted from the laser light source 11 will be referred to as the X-axis direction, and the horizontal direction perpendicular to the X-axis direction will be referred to as the Y-axis direction.

The laser light source 11 is a device that emits one laser beam B, and in this embodiment, emits a laser beam such as a YAG laser or a visible laser.

The beam expander 12 is a combination of lenses for expanding the diameter of the laser beam B emitted from the laser light source 11, and makes the laser beam B of a diameter suitable for splitting by the phase diffraction element 13 enter the phase diffraction element 13. In order to achieve this, the beam expander 12 adjusts the diameter of the laser beam B.

The phase diffraction element (DOE) 13 is configured by combining a plurality of diffraction gratings with different grating periods, and converts the shape of the laser beam B into an arbitrary shape by using a light diffraction phenomenon. It is something. The phase diffraction element 13 used in this embodiment is a plurality of phase diffraction elements arranged in a matrix shape with an equal pitch on a predetermined plane (when the laser beam B is incident from the X-axis direction, on the YZ plane). It is converted into a ray bundle B1 consisting of the rays of the book. Here, in the phase diffraction element 13 having the above configuration, not only the shape of the light beam but also the power of the light beam can be arbitrarily designed, and in this embodiment, the power of each light beam forming the beam bundle B1 is made uniform. , a phase diffraction element 13 is designed.

Note that a DOE is a device that divides a laser beam into a plurality of light beams obtained as a diffraction pattern using a diffraction grating, and obtains a light intensity distribution consisting of a desired diffraction pattern on a virtual plane located at a predetermined distance from the DOE. It is something. Therefore, in many cases, the desired light intensity distribution cannot be obtained on a surface other than the predetermined distance. Therefore, although the expression used in this specification to say that a laser beam is divided into a plurality of light beams is not strictly correct, for convenience, obtaining a light intensity distribution consisting of a plurality of diffraction patterns by the above-mentioned DOE is simply referred to as a plurality of light beams. It is expressed as dividing into.

FIG. 2 is an aa cross-sectional view in FIG. 1(a), and is a real image plane of the light beam B1. As described above, in this embodiment, the phase diffraction element 13 converts the laser beam B into a beam bundle B1 consisting of a plurality of beams arranged in a matrix with equal pitches on the YZ plane, and on the real image plane, As shown by the pitch P1 in a), light spots corresponding to the number of light rays forming the beam bundle B1 are arranged at equal pitches on the YZ plane. In this description, the light rays constituting the light beam B1 are illustrated as being arranged in a 3×3 matrix, but the number of light rays may be greater than this.

Here, in this embodiment, as described above, the zoom lens 14, which is the variable focus optical system of the present invention, is provided immediately downstream of the phase diffraction element 13. By changing the focal length (magnification in the zoom lens 14) of this variable focus optical system, it is possible to enlarge or reduce the pitch of the light spot. As shown by bundle B1', it is possible to arbitrarily change and adjust the pitch of each light beam of the light beam bundle forming the light spot image compared to the pitch P1 in FIG. 2(a).

As a specific example of irradiating the irradiated surface S with the interval between the light spot images arbitrarily adjusted, an example of a semiconductor chip transfer apparatus using the light spot image irradiation apparatus 1 of this embodiment is shown in FIGS. Shown in b).

By irradiating a light spot image onto the joint between the chip 21 and the carrier substrate 22, which is a flat base material in this description, the chip 21 is laser lifted off and transferred to the transfer substrate 23, as shown in FIG. 3(a). The image is transferred to the transfer target substrate 23. Specifically, the joint between the chip 21 and the carrier substrate 22 is decomposed by laser beam irradiation, gas is generated, and the chip 21 is energized by the generation of gas, and the chip 21 is moved from the carrier substrate 22 to the transfer substrate 23. fly to For example, when the chip 21 is a GaN chip, Ga and N are decomposed by laser light irradiation to generate N2, which expands and causes the chip 21 to be laser lifted off from the carrier substrate 22. In this case, the bonding surface between the chip 21 and the carrier substrate 22 corresponds to the irradiated surface S, and in this explanation, the set of parts on the irradiated surface S that are irradiated with the light beam are as shown in FIG. 1(b). This is called light spot image 2.

Here, when the chips 21 are arranged at equal intervals on the carrier substrate 22, by adjusting the interval of the light spot image 2 according to the interval between the chips and irradiating the light spot image 2, a plurality of chips 21 can be efficiently illuminated at the same time. Can be transcribed. Specifically, when the chips 21 are arranged at a pitch P1 as shown in FIG. When the chips 21 are arranged at a pitch of P1' as shown in (b), the zoom lens 14 is set so as to form a bundle of rays B1' in which the intervals between each light ray on the irradiated surface S are at a pitch of P1'. By performing the transfer of the chips 21, a plurality of chips 21 can be efficiently transferred at the same time.

On the other hand, as the interval between each light beam is adjusted by the zoom lens 14, the area of the light spot image irradiated onto the irradiated surface S also changes, and the area may not fall within an allowable range. Here, in this embodiment, each light ray is arranged on the real image plane so that the dimensions and shape of each light ray of the light ray bundle B1 forming the light spot image 2 irradiated onto the irradiated surface S become predetermined dimensions and shapes. An aperture member 18 is provided with an opening (aperture 19) corresponding to the area. Specifically, as shown in FIG. 2(a), for a bundle of rays B1 in which the interval between each ray is the pitch P1, the aperture member 18 in which the apertures 19 are arranged so that the interval is the pitch P1 is used. , as shown in FIG. 2(b), for a beam bundle B1' in which the interval between each ray is a pitch P1', an aperture member 18' in which apertures 19' are arranged so that the interval is a pitch P1' is used. The aperture member is provided so as to be replaceable or deformable. By doing so, it is possible to irradiate the irradiated surface S with a light spot image having a size and shape suitable for the purpose as well as a pitch suitable for the purpose.

Returning to FIG. 1, in this embodiment, each ray of the ray bundle B1, which is once imaged after passing through the zoom lens 14 which is a variable focus optical system, is made into parallel light by the collimating lens 15, and then by the Fθ lens 17. The light is focused and imaged again on the irradiated surface S. In this description, an optical system that images the light beam again is called an imaging optical system, and in this embodiment, the combination of the collimating lens 15 and the Fθ lens 17 corresponds to this imaging optical system. Further, in this embodiment, a galvanometer mirror 16 is provided between the collimating lens 15 and the Fθ lens 17.

The galvanometer mirror 16 has two mirrors, and by controlling the positions and angles of these mirrors, the incident light beam is emitted in an arbitrary direction. In this embodiment, the galvano mirror 16 functions as a light spot image shifting means for changing the position on the irradiated surface S where the light spot image 2 is irradiated. By having such a light spot image shifting means, it is possible to continuously irradiate the light spot images 2 to the irradiated objects arranged in a number greater than the number of light spot images 2 to be irradiated by one emission of the laser beam B. I can do it.

FIG. 4 is a diagram illustrating a process in which the light spot image irradiation device 1 sequentially irradiates the irradiated surface S with light beams. A plurality of light spot images 2 are simultaneously irradiated onto the irradiated surface S by the beam B1 emitted from the laser light source 11, split by the phase diffraction element 13, and reflected by the galvanometer mirror 16, as shown in FIG. 4(a). be done. After controlling the position and angle of each mirror of the galvanometer mirror 16, the laser light source 11 emits the laser light B again, so that a light spot image 2 on the irradiated surface S is generated as shown in FIG. 4(b). For example, adjacent chips 21 can be laser lifted off. Further, the laser beam B is emitted so that the interval between the irradiation positions of the light beam B1 due to the continuous emission of the laser beam B becomes a pitch P1, which is the interval between adjacent light spot images 2, as shown in FIG. 4(b). By performing this, the intervals between the light spot images can be made uniform.

By repeatedly controlling the position and angle of each mirror of the galvanometer mirror 16 and emitting the laser beam B from the laser light source 11 in this way, a matrix of light spot images 2 is sequentially irradiated as shown in FIG. 4(c). As a result, it is possible to transfer a chip group consisting of a plurality of chips 21 arranged and bonded to the carrier substrate 22 in a matrix onto the transfer target substrate 23 at high speed.

FIG. 5 is a diagram illustrating a light spot image irradiation device in another embodiment of the present invention. In the light spot image irradiation device 1 in this embodiment, the base material W having the irradiated surface S is used as a light spot image shifting means for changing the position on the irradiated surface S where the light spot image 2 is irradiated by the light beam B1. By suctioning and holding the irradiated surface S and moving it in the Y-axis direction, that is, by moving the irradiated surface S itself, the laser light source 11, beam expander 12, phase diffraction element 13, zoom lens 14, and a set of relay lenses 32 (imaging A moving stage 31 that relatively moves the entire optical system consisting of a mirror 33 (equivalent to an optical system) and a base material W is employed. By sequentially emitting laser beams B from the laser light source 11 while moving the base material W using the moving stage 31, the beam bundle B1 is emitted while changing the irradiation position in the Y-axis direction on the irradiated surface S of the base material W. It is possible to irradiate the irradiated surface S.

In this embodiment, the pitch between the light rays forming the light beam B1 can be adjusted by adjusting the magnification of the zoom lens 14, as in the embodiment described with reference to FIG. Furthermore, the pitch between the beam bundles B1 in the Y-axis direction can be adjusted by adjusting at least one of the moving speed of the moving stage 31 and the emission timing of the laser beam B from the laser light source 11.

With the above-described light spot image irradiation device and chip transfer device, it is possible to branch the light beam and irradiate the light beam with uniform power to any plurality of positions in the two-dimensional direction of the irradiated surface.

Here, the light spot image irradiation device and the chip transfer device of the present invention are not limited to the embodiments described above, but may have other embodiments within the scope of the present invention. For example, the optical spot image irradiation device of the present invention may be used not only for semiconductor chip transfer purposes but also for other purposes.

Further, in the light spot image irradiation device 1 shown in FIG. 5, if the area of the area to which the light spot image is irradiated is large, not only the moving means 31 in the Y-axis direction but also the moving means in the X-axis direction may be provided. Also, in the light spot image irradiation device 1 shown in FIG. 1, if the area of the area to be irradiated with the light spot image is large, a moving means for moving the base material having the irradiated surface S in the X-axis direction and the Y-axis direction is provided. It's okay. Furthermore, if all the objects on the irradiated surface can be irradiated with a light spot image by one irradiation with a beam of light, the light spot image shifting means may be omitted.

Furthermore, the light spot images formed by the phase diffraction element do not necessarily have to be arranged in a matrix as shown in FIG. For example, they may be arranged in a staggered manner.

1 Light spot image irradiation device 2 Light spot image 11 Laser light source 12 Beam expander 13 Phase diffraction element 14 Zoom lens (variable focus optical system)
15 Collimating lens 16 Galvano mirror (light spot image shifting means)
17 Fθ lens 18 aperture member 18' aperture member 19 aperture 19' aperture 21 chip 22 carrier substrate 23 transfer substrate 31 moving stage (light spot image shifting means)
32 Relay lens 33 Mirror B Laser light B1 Light beam B1' Light beam S Irradiated surface W Base material

Claims (3)

A light spot image generated by a light spot image irradiation device is irradiated onto a chip located at an arbitrary position among a plurality of chip groups arranged in a matrix on a flat base material, thereby covering the chip. It is a chip transfer device that transfers to the transfer surface,
The light spot image irradiation device irradiates a light spot image consisting of a plurality of light spots onto a surface to be irradiated, and includes a laser light source and a phase diffraction element that splits the laser light emitted from the laser light source into a plurality of light beams. , a variable focus optical system that is provided between the phase diffraction element and the irradiated surface and changes the pitch of the plurality of light rays by changing the focal length of the plurality of light rays, and the plurality of light rays. A chip transfer device comprising: a light spot image shifting means for shifting the light spot image according to the invention in an in-plane direction of the irradiated surface . An imaging optical system is further provided between the variable focus optical system and the irradiated surface for forming an image formed by the variable focus optical system onto the irradiated surface, and in the imaging optical system, 2. The chip transfer device according to claim 1, further comprising a galvano mirror optical system serving as said light spot image shifting means. 3. The chip transfer apparatus according to claim 1, wherein the light spot image shifting means includes a moving stage that moves the irradiated surface itself.

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