Patent Application
20250014936
The present invention relates to a transfer device and a transfer method for irradiating light energy on a transfer substrate and using blistering to transfer an element onto a receiving substrate.
In recent years, semiconductor chips have been reduced in size for the purpose of cost reduction, and efforts are being made to mount such miniaturized semiconductor chips with high precision. A so-called laser lift-off method has been employed to mount such miniaturized chips at a high speed, in which laser is irradiated on a bonding surface of a chip bonded to a transfer substrate to cause ablation, which causes the chip to detach from the transfer substrate and be biased, thereby being transferred onto a receiving substrate.
Japanese Laid-Open Patent Application Publication No. 2006-041500 (Patent Document 1) discloses an element transfer device that uses the ablation technique to transfer an element. In this element transfer device, a laser irradiation device, having a laser light source for generating a laser beam, a reflection means for reflecting the laser beam from the laser light source in a required direction, and a control means for controlling irradiation and non-irradiation of the laser beam in conjunction with the reflection means, is used to selectively irradiate the laser beam on some of a plurality of elements arranged on a transfer substrate to cause ablation in a layer holding the elements. This selective ablation causes some of the elements to be transferred onto the receiving substrate. That is, the elements are transferred from the transfer substrate to the receiving substrate by laser lift-off.
In addition, Japanese Translation of PCT International Application Publication No. 2014-515883 (Patent Document 2) discloses a technique in which a laser beam is irradiated on a blistering layer that is provided on a transfer substrate and that has an adhesive layer on the front surface side, to generate a blister (bulge) in the blistering layer, and an object (element) that is adhered to this adhesive layer is pushed out as a result of the generation of this blister, thereby separating the object from the transfer substrate.
However, in the element transfer devices disclosed in Patent Documents 1 and 2, the force with which the transfer substrate (transfer source substrate) holds the element may stay stronger than the force with which the element is separated even after the laser irradiation, so there is a risk that the element is not detached from the transfer substrate. In particular, if a blister is generated, due to ablation, in a portion of the transfer substrate that holds an element, even if one blister 130 is generated by irradiating laser on a blistering layer 124 that holds one element 121 on a transfer substrate 122, as shown in
In view of the problem described above, an object of the present disclosure is to provide a transfer device and a transfer method with which it is possible to reliably cause an element to detach from a transfer substrate and be transferred to a receiving substrate.
In order to solve the problem described above, a transfer device of the present disclosure is a transfer device configured to transfer an element held on a transfer substrate to a receiving substrate, the transfer device comprising an energy irradiation unit configured to irradiate an active energy ray toward the element through the transfer substrate in a state in which the transfer substrate and the receiving substrate face each other across the element, the transfer substrate having a blistering layer in which a blister is generated due to irradiation of the active energy ray and that is configured to hold the element, the receiving substrate having a capture layer that is arranged facing the transfer substrate to capture the element, and the energy irradiation unit being configured to form the blister in an element holding area, which is an area of the blistering layer that holds one element, to change a tilt of the element relative to the transfer substrate and to bring the element closer to the receiving substrate, thereby causing a portion of the element to come in contact with the capture layer first, in a state in which the blistering layer holds the element.
According to the transfer device of the present disclosure, the tilt of the element relative to the transfer substrate is changed and the element is brought closer to the receiving substrate, thereby making it easier for at least a portion of the element to come in contact with the capture layer as compared with bringing the element closer to the receiving substrate while maintaining a state in which the element is parallel with the transfer substrate, so that the element can be transferred onto the receiving substrate starting from that point.
In addition, the blister preferably shrinks over time.
As a result, the blistering layer naturally detaches from the element that has come in contact with the capture layer, without having to wait for the transfer substrate and the receiving substrate to separate from each other.
In addition, the blister is preferably formed such that a center of the blister is positioned at a peripheral portion of the element holding area other than a center thereof.
As a result, even if only one blister is formed, it is possible to create a state in which the element is tilted with respect to the transfer substrate.
Preferably, at least two of the blisters are formed in sequence in the element holding area.
As a result, it is possible to stably maintain a state in which the element is tilted relative to the transfer substrate.
In addition, preferably, when a large blister and a small blister having different volumes are formed in the element holding area, the small blister is formed first, and, in a state in which the element is tilted by the small blister, the large blister is formed where a gap between the transfer substrate and the element is smaller than that of a location where the small blister is formed.
As a result, a portion of the element is detached from the blistering layer due to the formation of the small blister before a large tilt is generated due to the large blister, so it is possible to reduce load that is applied to the element at the time of the large blister formation.
In addition, three or more blisters, each having a different volume, are preferably formed in the element holding area so as to be arranged in order of volume.
As a result, it is possible to more stably maintain a state in which the element is tilted relative to the transfer substrate.
In addition, preferably, a large blister and a small blister having different volumes are formed in the element holding area so as to be connected to each other, and gas inside the small blister moves into the large blister so that the large blister expands toward the receiving substrate.
As a result, as the large blister expands toward the receiving substrate, the tilt of the element becomes larger than prior to the expansion and the entire element further approaches the capture layer, so that the element can more reliably be transferred to the receiving substrate.
In addition, the large blister and the small blister are preferably connected via a thin linear blister.
As a result, it is possible to easily create a state in which the large blister and the small blister are connected to each other.
In addition, in order to solve the problem described above, a transfer device of the present disclosure is a transfer device configured to transfer an element held on a transfer substrate to a receiving substrate, the transfer device comprising an energy irradiation unit configured to irradiate an active energy ray toward the element through the transfer substrate in a state in which the transfer substrate and the receiving substrate face each other across the element, the transfer substrate having a blistering layer in which a blister is generated due to irradiation of the active energy ray and that is configured to hold the element, the receiving substrate having a capture layer that is arranged facing the transfer substrate to capture the element, and the energy irradiation unit being configured to form a large blister and a small blister having different volumes in an element holding area, which is an area of the blistering layer that holds one element, so as to be connected to each other, and gas inside the small blister moving into the large blister so that the large blister expands toward of the receiving substrate, thereby causing the element to come in contact with the capture layer in a state in which the blistering layer holds the element.
According to the transfer device of the present disclosure, as the large blister expands toward the receiving substrate, the entire element comes closer to the capture layer than prior to the expansion, so that the element can more reliably be transferred to the receiving substrate.
In addition, in order to solve the problem described above, a transfer method of the present disclosure is a transfer method for transferring an element held on a transfer substrate to a receiving substrate, the transfer method comprising irradiating an active energy ray toward the element through the transfer substrate in a state in which the transfer substrate and the receiving substrate face each other across the element, to cause the element to detach from the transfer substrate and move to the receiving substrate, the transfer substrate having a blistering layer in which a blister is generated due to irradiation of the active energy ray and that is configured to hold the element, the receiving substrate having a capture layer that is arranged facing the transfer substrate to capture the element, and in the irradiating of the active energy ray, the blister being formed in an element holding area, which is an area of the blistering layer that holds one element, to change a tilt of the element relative to the transfer substrate and to bring the element closer to the receiving substrate, thereby causing a portion of the element to come in contact with the capture layer first in a state in which the blistering layer holds the element.
According to the transfer method of the present disclosure, the tilt of the element relative to the transfer substrate is changed and the element is brought closer to the receiving substrate, thereby making it easier for at least a portion of the element to come in contact with the capture layer as compared with bringing the element closer to the receiving substrate while maintaining a state in which the element is parallel with the transfer substrate, so that the element can be transferred onto the receiving substrate starting from that point.
In addition, in order to solve the problem described above, a transfer method of the present disclosure is a transfer method for transferring an element held on a transfer substrate to a receiving substrate, the transfer method comprising irradiating an active energy ray toward the element through the transfer substrate in a state in which the transfer substrate and the receiving substrate face each other across the element, to cause the element to detach from the transfer substrate and move to the receiving substrate, the transfer substrate having a blistering layer in which a blister is generated due to irradiation of the active energy ray and that is configured to hold the element, the receiving substrate having a capture layer that is arranged facing the transfer substrate to capture the element, and in the irradiating of the active energy ray, a large blister and a small blister having different volumes being formed in an element holding area, which is an area of the blistering layer that holds one element, so as to be connected to each other, and gas inside the small blister moving into the large blister so that the large blister expands toward the receiving substrate, thereby causing the element to come in contact with the capture layer in a state in which the blistering layer holds the element.
According to the transfer method of the present disclosure, as the large blister expands toward the receiving substrate, the entire element comes closer to the capture layer than prior to the expansion, so that the element can more reliably be transferred to the receiving substrate.
According to the transfer device and the transfer method of the present disclosure, it is possible to reliably cause an element to detach from a transfer substrate and be transferred to a receiving substrate.
A transfer device according to one embodiment of the present disclosure will be described, with reference to
The transfer device 10 comprises a laser irradiation unit 12 that irradiates laser light 11, a transfer substrate holding unit 13 that can hold and move a transfer substrate 22 at least in an X-axis direction and a Y-axis direction, a receiving substrate holding unit 14 that is below the transfer substrate holding unit 13 and holds a receiving substrate 23 so as to face the transfer substrate 22 with a gap therebetween, and a control unit or electronic controller C. The transfer device 10 irradiates the laser light 11 onto the transfer substrate 22 to cause ablation in the transfer substrate, thereby transferring an element 21 from the transfer substrate 22 to the receiving substrate 23.
The laser irradiation unit 12 is one embodiment of an energy irradiation unit in the present disclosure. The laser irradiation unit 12 is a laser (e.g., a laser emitter device) that irradiates the laser light 11, such as an excimer laser, which is an active energy ray, and is provided fixed to the transfer device 10. In the present embodiment, the laser irradiation unit 12 irradiates the spot-shaped laser light 11, the irradiation position of the laser light 11 in the X-axis direction and the Y-axis direction is controlled via an fθ lens 16 and a galvano mirror 15 whose angle is adjusted by the control unit CU, and the laser light 11 selectively irradiates a plurality of the elements 21 arranged on the transfer substrate 22 held by the transfer substrate holding unit 13. When the laser light 11 enters near the element 21 through the transfer substrate 22, ablation occurs between the transfer substrate 22 and the element 21 due to the application of active energy (light energy). This ablation biases the element 21, and the element 21 is transferred from the transfer substrate 22 to the receiving substrate 23. In this description, the element 21 is, for example, a semiconductor chip. In the illustrated embodiment, the control unit CU includes at least one processor having a CPU (Central Processing Unit) and a storage device or computer memory, and an interface for each device is included as necessary. The control unit CU is operatively coupled to the laser irradiation unit 12 to control the timing and intensity of the irradiation of the laser light 11 by the laser irradiation unit 12. The control unit CU is also operatively coupled to electronic actuators of the galvano mirror 15 to adjust the angle of the galvano mirror 15, thereby adjusting the position of the irradiation of the laser light 11 on the transfer substrate 22. With this configuration, the control unit CU can control the ablation occurred between the transfer substrate 22 and the element 21 in a manner described below.
The transfer substrate holding unit 13 has an opening, and uses suction to hold the vicinity of the outer periphery of the transfer substrate 22. It is possible to irradiate the laser light 11 that is emitted from the laser irradiation unit 12 onto the transfer substrate 22, which is held by the transfer substrate holding unit 13, via this opening.
The transfer substrate 22 is a substrate made of glass, or the like, that can transmit the laser light 11, and that holds the element 21 on the bottom surface side thereof. In addition, a blistering layer 24 is formed on the surface of the transfer substrate 22 that holds the element 21, as shown in
In addition, the transfer substrate holding unit 13 has a movement mechanism, such as at least one electronic actuator, to move relative to the receiving substrate holding unit 14 in at least the X-axis direction and the Y-axis direction. In particular, the control unit CU is operatively coupled to the movement mechanism of the transfer substrate holding unit 13 to control the movement mechanism for adjusting the position of the transfer substrate holding unit 13. Thus, it is possible to adjust the relative position of the element 21 held by the transfer substrate 22 relative to the receiving substrate 23. Furthermore, the transfer substrate holding unit 13 also includes an electronic actuator that is operatively connected to the control unit CU to generate suction force to hold the vicinity of the outer periphery of the transfer substrate 22.
The receiving substrate holding unit 14 has a flat upper surface, and, during the transfer step of the element 21, holds the receiving substrate 23 such that blistering layer 24 of the transfer substrate 22 and the element 21 held by the blistering layer 24 face the receiving surface of the receiving substrate 23. A plurality of suction holes are provided on the upper surface of the receiving substrate holding unit 14, which hold the rear surface of the receiving substrate 23 (the surface on which the element 21 is not transferred) using suction force. Thus, the receiving substrate holding unit 14 also includes an electronic actuator that is operatively connected to the control unit CU to generate the suction force to hold the rear surface of the receiving substrate 23.
Here, the receiving substrate 23 in the present embodiment is a substrate made of glass, etc., and, as shown in
In the present embodiment, only the transfer substrate holding unit 13 is moved in the X-axis direction and the Y-axis direction to move the transfer substrate holding unit 13 and the receiving substrate holding unit 14 relative to each other, but if the dimensions of the receiving substrate 23 are large and the entire surface of the receiving substrate 23 cannot be placed directly below the irradiation range of the laser light 11, the receiving substrate holding unit 14 may also be provided with a movement mechanism, such as at least one electronic actuator, in the X-axis direction and the Y-axis direction. In this case, the control unit CU is operatively coupled to the movement mechanism of the receiving substrate holding unit 14 to control the movement mechanism for adjusting the position of the receiving substrate holding unit 14.
In the transfer device 10 having the configuration described above, the laser light 11 is irradiated toward the element 21 through the transfer substrate 22 in a state in which the transfer substrate 22 and the receiving substrate 23 are facing each other across the element 21, and the laser light 11 is irradiated on the blistering layer 24; the energy of the laser light 11 thereby decomposes a part of the material of the blistering layer 24, generating gas. Due to the decomposition of the material of the blistering layer 24 and the generation of gas, a blister (air bubble) 30 is generated inside the blistering layer 24 or between the blistering layer 24 and the glass surface 22a of the transfer substrate 22, as shown in
One embodiment of a transfer method using the transfer device 10 of the present disclosure will be described, with reference to
As shown in
The distance between the glass surface 22a and the surface of the adhesive blistering layer 24 where such blistering has occurred is larger than the distance between the surface of the blistering layer 24 and the glass surface 22a before blistering occurs. Therefore, when blistering occurs in the blistering layer 24 in the element holding area 24a, the element 21 separates from the glass surface 22a of the transfer substrate 22 while being held on the surface portion of the blistering layer 24.
In the present embodiment, since the receiving substrate 23 is provided near, and facing, the element 21 with a prescribed gap therebetween, the element 21 approaches the capture layer 25 of the receiving substrate 23 as a result of the occurrence of blistering, while being held on the surface portion of the blistering layer 24.
In the present embodiment, only one of the blister 30 is formed in the element holding area 24a, and the blister 30 is formed such that the center of the blister 30 is positioned at a location other than the center of the element holding area 24a (the dashed-dotted line in
As a result of the portion Q of the element 21 coming in contact with the capture layer 25 first, at least a portion of the element 21 is adhesively held by the capture layer 25. Here, if the adhesive holding strength of the capture layer 25 with respect to the element 21 is larger than the adhesive holding strength of the blistering layer 24 with respect to the element 21, when the capture layer 25 and the blistering layer 24 separate and the capture layer 25 and the blistering layer 24 both pull on the element 21, the blistering layer 24 will detach from the element 21 and the capture layer 25 will hold the entire surface of the element 21. That is, the transfer of the element 21 from the transfer substrate 22 to the receiving substrate 23 is completed.
In this manner, by forming the blister 30 in the element holding area 24a of the blistering layer 24 and causing the element 21 to approach the receiving substrate 23 while being tilted relative to the transfer substrate 22, it becomes easier for at least a portion of the element 21 to come in contact with the capture layer 25 as compared with bringing the element 21 close to the receiving substrate 23 while maintaining a state in which the element 21 is parallel with the transfer substrate 22, so that the element 21 can be transferred onto the receiving substrate 23 starting from that point.
In addition, in the case of a configuration in which the element 21 is brought in contact with the capture layer 25 in a state of being held by the blistering layer 24, as in the present disclosure, that is, a configuration in which the element 21 is transferred from the transfer substrate 22 to the receiving substrate 23 while constantly being held by something, there is less influence of air resistance and the transfer is carried out with better positional accuracy, as compared with a case in which transfer is carried out by the element being separated from the transfer substrate and falling to the receiving substrate, as is the case with the comparative laser lift-off method. Furthermore, with this configuration, the transfer can be carried out while the transfer substrate holding unit 13 and the receiving substrate holding unit 14 are stationary relative to each other. In other words, the transfer can be carried out without relatively moving the transfer substrate holding unit 13 and the receiving substrate holding unit 14 toward each other.
There are cases in which the blister 30 shrinks, such as when gas, which forms the blister 30 by the irradiation of an active energy ray, contracts due to a decrease in the temperature of the blister 30, or diffuses into the blistering layer 24. In this case, the blistering layer 24 naturally detaches from the element 21 that has come in contact with the capture layer 25 due to the blister 30 shrinking, without having to wait for the transfer substrate 22 and the receiving substrate 23 to separate from each other, after irradiation of the active energy ray on all of the elements 21 on the transfer substrate 22, thereby completing the transfer of the elements 21.
A transfer method according to another embodiment of the present disclosure will be described next, with reference to
In the present embodiment, the laser light 11 is irradiated on two locations in the element holding area 24a, forming two blisters (large blister 30a and small blister 30b), and the volume of each blister is different from each other. Blisters having different volumes in this manner can be formed by varying the power, the number of times of the irradiation, etc., of the laser light 11 required for the formation of the blisters. In addition, in the present embodiment, blisters are formed in ascending order of volume.
In this manner, due to the presence of at least two blisters with different volumes, that is, with different heights from the glass surface 22a, the element 21 separates from the glass surface 22a so as to be tilted relative to the transfer substrate 22, and such a separated state can be more stably maintained as compared with a case in which the number of blisters is small.
In addition, in the present embodiment, when forming the large blister 30a and the small blister 30b having different volumes in the element holding area 24a, the small blister 30b is formed first, and, in a state in which the element 21 is tilted by the small blister 30b, the large blister 30a is formed where the gap between the transfer substrate 22 and the element 21 is smaller than that of the location where the small blister 30b is formed, as shown in
A plurality of blisters may have the same volume. In this case, by sequentially forming blisters in one direction starting from a blister located at the end of the element holding area 24a, the tilt of the element 21 can be increased each time a blister is formed.
Here, the number of blisters to be formed in the element holding area 24a is not limited to two, and may be three or more. In this case, as a result of those blisters being formed in the element holding area 24a so as to be arranged in order of volume, it is possible to more stably maintain a state in which the element 21 is tilted relative to the transfer substrate 22. A transfer method according to yet another embodiment of the present disclosure will be described next, with reference to
In the present embodiment, two blisters (large blister 30c and small blister 30d) having different volumes are formed in the element holding area 24a. The large blister 30c and the small blister 30d are connected with each other at a connecting portion 31. The blistering layer 24 has some elasticity, and the state created by the large blister 30c, the small blister 30d, and the blistering layer 24 surrounding the blisters, is similar to a state in which the openings of two balloons that have been inflated to different sizes are connected to each other.
If the openings of two balloons inflated to different sizes are connected, since the internal pressure of the small balloon is higher than the internal pressure of the large balloon, the small balloon becomes smaller and the gas inside the balloon moves to the large balloon, further increasing the size of the large balloon.
A process by which the shape of a blister changes in the transfer method of the present embodiment will be described, with reference to
As a result of the large blister 30c becoming larger, the large blister 30c expands toward the receiving substrate 23, and the height dimension of the large blister 30c changes from H1 to H1+ΔH, as shown in
Here, in particular, in the present embodiment, each blister is formed at a boundary between the blistering layer 24 and the glass surface 22a of the transfer substrate 22, as shown in
As a result of the large blister 30c expanding in the direction in which the aspect ratio increases, the height increase ΔH becomes larger as compared with a case in which the dimensions increase in all directions, so that the tilt of the element 21 can be made even larger. In addition, when forming a blister having a prescribed height dimension, the volume can be kept relatively small, so that the power, the number of times of irradiation, etc., of the laser light 11 to irradiate can be reduced.
In addition, in the present embodiment, when forming the large blister 30c and the small blister 30d having different volumes in the element holding area 24a, the small blister 30d is formed first, and, in a state in which the element 21 is tilted by the small blister 30d, the large blister 30c is formed where the gap between the transfer substrate 22 and the element 21 is smaller than that of the location where the small blister 30b is formed, as shown in
A transfer method according to yet another embodiment of the present disclosure will be described next, with reference to
In the present embodiment, the laser light 11 is irradiated on the blistering layer 24 forming the element holding area 24a such that four blisters having different volumes, blister 30e, blister 30f, blister 30g, and blister 30h, are formed in order of the volume, along a diagonal line of the element holding area 24a. In addition, adjacent blisters are connected by a connecting portion 32, which is a thin linear blister.
Even when two or more blisters are connected in this manner, in the same manner as in the previous embodiment, gas moves from the small blister to the large blister, so that gas moves from the smallest blister 30h to the second smallest blister 30g, then the gas moves from this blister 30g to the second largest blister 30f, and the gas moves from this blister 30f to the largest blister 30e. Ultimately, the gas of all blisters except for the largest blister 30e contribute to the expansion of the blister 30e, so that the power, the number of times of irradiation, etc., of the laser light 11 can be reduced as compared with a case in which a blister having the same height as the expanded blister 30e is formed of a single blister. The order of formation of the blisters in this case is: the blister 30h, the blister 30g, the blister 30f, the blister 30e, and each of the connecting portions 32.
In addition, by forming a plurality of blisters along a diagonal line, which is the longest possible line segment within the rectangular element holding area 24a, as in the present embodiment, more blisters can be arranged, and the height dimension of the largest blister (blister 30e) can be increased.
Additionally, with a configuration in which thin linear connecting portions 32 are formed by irradiation of the laser light 11 and the blisters are connected to each other by these connecting portions 32, as in the present embodiment, it is possible to easily achieve a configuration in which the blisters are connected to each other.
A transfer method according to yet another embodiment of the present disclosure will be described next, with reference to
In the present embodiment, a largest blister 30i is formed at the center of the element holding area 24a, and blisters 30j are formed at four corners thereof so as to be connected to the blister 30i via the connecting portions 32. In this manner, the blisters do not necessarily need to be connected one-to-one, and a plurality of blisters may be connected to one blister.
Here, in the present embodiment, since the blister 30i is formed at the center of the element holding area 24a, the element 21 will not be tilted relative to the transfer substrate 22, as in the above-mentioned embodiments; however, the blister 30i expands due to the presence of the blisters 30j that supply gas to this blister 30i, so that the element 21 approaches the capture layer 25, increasing the possibility of coming in contact with the capture layer 25.
In addition, in the present embodiment, gas moves from a plurality of the blisters 30j to the blister 30i, so, compared to a case in which there is only one blister 30j, the degrees to which the volume of the blister 30i increases and to which the blister 30j expands toward the receiving substrate 23 become larger. As a result, the element 21 comes closer to the capture layer 25, increasing the possibility of coming in contact with the capture layer 25. A transfer method according to yet another embodiment of the present disclosure will be described next, with reference to
In the present embodiment, a blister 30k is formed in the element holding area 24a, and thin linear connection portions 33 are arranged vertically and horizontally so as to be directly or indirectly connected to the blister 30k. Gas can also move from these connected portions 33 to the blister 30k, so that the blister 30k may increase in volume and expand toward the receiving substrate 23.
According to the transfer device and the transfer method described above, it is possible to reliably cause an element to detach from a transfer substrate and be transferred to a receiving substrate.
Here, the transfer device and the transfer method of the present disclosure are not limited to the embodiments described above, and may take other forms within the scope of the present disclosure. For example, in the foregoing description, the blistering layer and the capture layer hold the element using adhesive force, but the element may be held by a holding force other than adhesive force.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-051687 | Mar 2022 | JP | national |
This application is a continuation application of PCT International Application No. PCT/JP2023/012307 filed on Mar. 27, 2023, which claims priority to Japanese Patent Application No. 2022-051687 filed on Mar. 28, 2022 with Japan Patent Office. The entire disclosures of PCT International Application No. PCT/JP2023/012307 and Japanese Patent Application No. 2022-051687 are hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/012307 | Mar 2023 | WO |
| Child | 18893241 | US |
