Element transfer method and element transfer device

Abstract

Provided is an element transfer method capable of transferring an element while suppressing breakage of the element caused by deformation of an adhesive layer, even when the element has a relatively small thickness. More specifically, this semiconductor chip transfer method (element transfer method) comprises: an disposition step in which an adhesive layer 2, a resist 3, and a semiconductor chip 1 are disposed in this order on a transfer substrate 10; and a transfer step in which the semiconductor chip 1 is transferred to a transfer-receiving substrate 20 by irradiating the transfer substrate 10 with laser light L from the side opposite to the surface of the transfer substrate on which the semiconductor chip 1 is disposed. The adhesive force between the adhesive layer 2 and the resist 3 is larger than the adhesive force between the resist 3 and the semiconductor chip 1, and thus in the transfer step, the resist 3 remains on the transfer substrate 10 side.

Description

Element transfer method and element transfer device

[0001] The present invention relates to an element transferring method and an element transferring apparatus, and more particularly to an element transferring method and an element transferring apparatus for transferring elements by irradiating them with laser light.

[0002] 2. Description of the Related Art Conventionally, there has been known an element transfer method in which an element is transferred by irradiating it with laser light (see, for example, Japanese Patent Application Laid-Open No. 2003-149998).

[0003] Patent Document 1 discloses a laser transfer method for transferring an article attached to a substrate to another substrate. In Patent Document 1, a blistering layer that deforms when irradiated with laser light and an adhesive layer are provided between the substrate and the article, and the article is held by the adhesive layer. In Patent Document 1, laser light is irradiated from the upper surface side of the substrate toward the blistering layer adjacent to the adhesive layer, and the blistering layer deforms, causing the adhesive layer to deform into a downward convex shape. As a result, the article is peeled off from the adhesive layer and transferred to another substrate.

[0004] Special Publication No. 2014-515883

[0005] In the conventional element transfer method described in Patent Document 1, when the thickness of the article (element) is relatively small, deformation of the adhesive layer (sticky layer) during transfer causes bending stress to be applied to the element, which may result in damage to the element. Therefore, there is a demand for an element transfer method and an element transfer device that can transfer elements while suppressing damage to the elements, even when the element is relatively thin.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an element transfer method and element transfer device that are capable of transferring elements while suppressing damage to the elements caused by deformation of the adhesive layer, even in the case of elements with a relatively small thickness.

[0007] In order to achieve the above object, an element transfer method according to a first aspect of the present invention comprises an arrangement step of arranging an adhesive layer, a release layer, and an element in this order on a first substrate, and a transfer step of irradiating laser light toward the first substrate from the side opposite to the surface on which the element is arranged on the first substrate to transfer the element to a second substrate, wherein the adhesive force between the adhesive layer and the release layer is greater than the adhesive force between the release layer and the element, and during the transfer step, the release layer remains on the first substrate side.

[0008] As described above, in the element transfer method according to the first aspect, the adhesive force between the adhesive layer and the release layer is greater than the adhesive force between the release layer and the element, and the release layer remains on the first substrate during the transfer process. This reduces the adhesive force between the release layer and the element, thereby reducing the bending stress imparted to the element by the deformed release layer due to deformation of the adhesive layer. Therefore, even if the element is relatively fragile, such as an element with a relatively small thickness, damage to the element can be suppressed. As a result, an element transfer method can be provided that transfers an element while suppressing damage to the element due to deformation of the adhesive layer. Furthermore, because the release layer remains on the first substrate, unlike when the release layer is transferred to the second substrate, the process of removing the release layer from the second substrate is eliminated, thereby reducing the time required for subsequent processes after the element transfer process.

[0009] In the element transfer method according to the first aspect, the placement step preferably includes a step of placing the element on the first substrate via an adhesive layer and a release layer containing resist. Here, in the element manufacturing process, resist may be formed on the upper surface of the element (the side of the element opposite the surface where the element faces the manufacturing substrate). Generally, the resist is transferred to the second substrate together with the element and removed from the second substrate in a removal step subsequent to the element transfer step. Therefore, if the release layer is configured to contain resist, the resist remains on the first substrate during the element transfer step. As a result, the step of removing the resist from the second substrate is eliminated, thereby reducing the time required for the steps subsequent to the element transfer step.

[0010] In the element transfer method according to the first aspect, the placement step preferably includes a step of placing the element on the first substrate via an adhesive layer and a release layer having a longitudinal elastic modulus greater than that of the element. With this configuration, the release layer has a longitudinal elastic modulus greater than that of the element, so that the degree of deformation of the release layer is greater than the degree of deformation of the element. This can promote the release of the element. As a result, the element can be easily released.

[0011] In this case, the transfer step preferably includes a step of transferring the element while forming a gap between the release layer and the element by irradiating the element with laser light due to the difference in the degree of deformation caused by the difference in the Young's modulus between the release layer and the element. In this configuration, the gap formed between the release layer and the element reduces the overall adhesive force between the release layer and the element, and can promote peeling of the element while leaving the release layer on the first substrate. As a result, by transferring the element while forming a gap between the release layer and the element, it is possible to more easily peel off only the element.

[0012] In the element transfer method according to the first aspect, the disposing step preferably includes a step of disposing an element having a thickness smaller than that of the release layer on the first substrate. In this way, even for an element having an extremely small thickness, such as a thickness smaller than that of the release layer, making the adhesive force between the release layer and the element relatively small is particularly effective in preventing damage to the element.

[0013] In the element transfer method according to the first aspect, the transfer step preferably includes a step of irradiating a laser beam having a spot area smaller than the area of ​​the element. Here, when the power density of the laser beam is the same, the larger the area of ​​the spot area, the greater the height of the deformed portions of the adhesive layer and the release layer. In other words, when an element is transferred using a laser beam having a spot area equal to or larger than the area of ​​the element, the height of the deformed portions of the adhesive layer and the release layer becomes relatively large, which increases the bending stress on the element and makes the element more susceptible to damage. Therefore, if the element is transferred using a laser beam having a spot area smaller than the area of ​​the element, the height of the deformed portions of the adhesive layer and the release layer becomes relatively small, thereby reducing the bending stress on the element and preventing damage to the element. As a result, the element can be transferred while preventing damage to the element due to deformation of the adhesive layer.

[0014] An element transfer device according to a second aspect of the present invention comprises a first substrate holding unit that holds a first substrate on which an adhesive layer, a release layer, and an element are arranged in that order, and a laser light irradiation unit that is arranged on the side of the first substrate opposite to the surface on which the element is arranged and irradiates laser light toward the first substrate to transfer the element to the second substrate, wherein the adhesive force between the adhesive layer and the release layer is greater than the adhesive force between the release layer and the element, and the laser light irradiation unit is configured to transfer the element so that the release layer remains on the first substrate side.

[0015] In the device transfer device according to the second aspect, as described above, the adhesive force between the adhesive layer and the release layer is greater than the adhesive force between the release layer and the device, and the laser light irradiation unit is configured to transfer the device so that the release layer remains on the first substrate. This relatively small adhesive force between the release layer and the device reduces the bending stress imparted to the device by the deformed release layer due to deformation of the adhesive layer. Therefore, even if the device is relatively fragile, such as a device with a relatively small thickness, damage to the device can be suppressed. As a result, a device transfer device can be provided that transfers devices while suppressing damage to the device due to deformation of the adhesive layer. Furthermore, because the release layer remains on the first substrate, the process of removing the release layer from the second substrate, which is required when the release layer is transferred to the second substrate, is eliminated, thereby reducing the time required for processes after the device transfer process.

[0016] As described above, the element transfer method and element transfer apparatus of the present invention can transfer elements while suppressing damage to the elements caused by deformation of the adhesive layer, even in the case of elements with a relatively small thickness.

[0017] FIG. 1 is a schematic diagram showing the overall configuration of a semiconductor chip transfer apparatus according to an embodiment; FIG. 2 is a plan view showing a state in which a semiconductor chip according to an embodiment is placed on a transfer substrate; FIG. 3 is a cross-sectional view of a semiconductor chip transfer apparatus according to an embodiment; FIG. 4 is a diagram for explaining a spot area of ​​laser light according to an embodiment; FIG. 5 is a flowchart for explaining processing of a semiconductor chip transfer method according to an embodiment; FIG. 6 is a schematic diagram for explaining steps of a semiconductor chip transfer method according to an embodiment; FIG. 7 is a diagram showing the state of a semiconductor chip when the adhesive force between an adhesive layer and a resist is greater than the adhesive force between the resist and a sacrificial layer according to an embodiment; FIG. 8 is a diagram showing the state of a semiconductor chip when the adhesive force between the adhesive layer and a resist is greater than the adhesive force between the resist and a sacrificial layer as a comparative example; FIG. 9 is a schematic diagram for explaining a subsequent step in the process of transferring a semiconductor chip to a transfer substrate according to an embodiment; and FIG. 10 is a diagram showing the state of a semiconductor chip when a sacrificial layer is not provided on the semiconductor chip according to a modified example.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0019] The configuration of a semiconductor chip transfer apparatus 100 according to one embodiment of the present invention will be described with reference to Figures 1 to 4. The semiconductor chip transfer apparatus 100 is an example of the "element transfer apparatus" in the claims.

[0020] 1, a semiconductor chip transfer device 100 is configured to transfer a semiconductor chip 1 arranged on a transfer substrate 10 to a transferee substrate 20 by a laser lift-off method. The transfer substrate 10 is an example of a "first substrate" in the claims. The transferee substrate 20 is an example of a "second substrate" in the claims.

[0021] The semiconductor chip transfer device 100 comprises a transfer substrate holding unit 30, a transferee substrate holding unit 40, a moving mechanism 50, a control unit 60, and a laser light irradiation unit 70. In the drawings, the left-right direction of the semiconductor chip transfer device 100 (one direction in a horizontal plane) is defined as the X direction. The up-down direction (vertical direction) of the semiconductor chip transfer device 100 is defined as the Z direction. The upward direction is defined as the Z1 direction, and the downward direction is defined as the Z2 direction. The direction perpendicular to the X and Z directions of the semiconductor chip transfer device 100 (the other direction in a horizontal plane) is defined as the Y direction. The transfer substrate holding unit 30 is an example of a "first substrate holding unit" in the claims.

[0022] 2, a plurality of semiconductor chips 1 are arranged in a matrix at predetermined intervals on the transfer substrate 10. The transfer substrate 10 has a circular shape. The semiconductor chip 1 is, for example, a thin element such as an InP chip, which has a rectangular shape with a side length of several tens of μm or more and a few mm or less and a thickness of 200 nm or more and 800 nm or less.

[0023] As shown in Figure 3, the transfer substrate 10 is formed of a material that transmits laser light L, such as a SiO2 (silicon dioxide) substrate or a sapphire substrate. The semiconductor chip 1 is disposed on the transfer substrate 10 via an adhesive layer 2, a resist 3, and a sacrificial layer 4. The resist 3 is an example of a "peeling layer" in the claims. The sacrificial layer 4 and the semiconductor chip 1 are both examples of an "element" in the claims. The adhesive layer 2 is also called a transfer material.

[0024] The adhesive layer 2 is disposed on the Z2-side surface 10a of the transfer substrate 10. The resist 3 is disposed on the Z2-side surface 2a of the adhesive layer 2. The sacrificial layer 4 is disposed on the Z2-side surface 3a of the resist 3. The semiconductor chip 1 is disposed on the Z2-side surface 4a of the sacrificial layer 4. The adhesive layer 2 is formed from a material that decomposes and generates gas components when irradiated with laser light L from the laser light irradiation unit 70. Then, by generating the gas components, the adhesive layer 2 deforms into a convex shape that protrudes toward the Z2 side (see FIG. 7). The adhesive layer 2 is formed from, for example, polyimide or silicon.

[0025] The resist 3 is formed as a protective film (mask) when processing (patterning) the substrate in the manufacturing process of the semiconductor chip 1. For example, "MICROPOSIT S1800 SERIES PHOTO RESIST" is used as the resist 3. The sacrificial layer 4 is formed to protect the surface of the semiconductor chip 1 in the manufacturing process of the semiconductor chip 1. The sacrificial layer 4 is also formed by growing crystals on the surface of the semiconductor chip 1 in the manufacturing process of the semiconductor chip 1. The semiconductor chip 1 and the sacrificial layer 4 are in contact with each other via chemical bonding. The sacrificial layer 4 is formed of, for example, SiON.

[0026] As shown in FIG. 1 , the transfer substrate holding unit 30 holds a transfer substrate 10 on which a semiconductor chip 1 is arranged via an adhesive layer 2, a resist 3, and a sacrificial layer 4. The transfer substrate holding unit 30 holds the transfer substrate 10 on which the semiconductor chip 1 is arranged, with the surface on which the semiconductor chip 1 is arranged facing downward (in the Z2 direction). The transfer substrate holding unit 30 has an opening 31. The transfer substrate 10 held by the transfer substrate holding unit 30 is irradiated with laser light L from a laser light irradiation unit 70 through the opening 31. The transfer substrate holding unit 30 is configured to be movable relative to the transferred substrate holding unit 40 in at least the X and Y directions by a movement mechanism 50.

[0027] 3, the transfer substrate 20 is a substrate onto which a large number of semiconductor chips 1 arranged on a transfer substrate 10 are transferred, for example, to manufacture a semiconductor product. An adhesive layer 21 for adhering the transferred semiconductor chips 1 is formed on the transfer substrate 20. The adhesive layer 21 is also called a catch layer. The transfer substrate 20 may also have wiring formed thereon that can be electrically connected to the transferred semiconductor chips 1. The transfer substrate 20 has a rectangular shape.

[0028] The transfer substrate holding unit 40 holds the transfer substrate 20, onto which the semiconductor chip 1 arranged on the transfer substrate 10 is transferred, from below (Z2 side). The transfer substrate holding unit 40 is configured to be movable relative to the transfer substrate holding unit 30 in at least the X and Y directions by a movement mechanism 50 (see FIG. 1). By moving one or both of the transfer substrate holding unit 30 and the transfer substrate holding unit 40 by the movement mechanism 50, it is possible to adjust the relative position of the semiconductor chip 1 arranged on the transfer substrate 10 with respect to the transfer substrate 20.

[0029] 1, the control unit 60 is configured with a processor such as a CPU (Central Processing Unit) and performs various controls by executing programs (software). The control unit 60 arbitrarily selects a semiconductor chip 1 in the transfer area and controls the laser light irradiation unit 70 to irradiate it with laser light L, thereby transferring the selected semiconductor chip 1 to the transfer substrate 20. The control unit 60 also controls the operation of the moving mechanism 50 and the opening and closing operation of the slit 74.

[0030] The laser light irradiation unit 70 is configured to irradiate the transfer substrate 10 with laser light L. The laser light irradiation unit 70 includes a laser light source 71, a galvanometer mirror 72, and an fθ lens 73. The laser light source 71 is a light source that emits laser light L. The galvanometer mirror 72 is rotatable about two intersecting axes as rotation axes, and reflects the laser light L at an arbitrary angle. The fθ lens 73 focuses the laser light L reflected by the galvanometer mirror 72 onto the transfer region of the transfer substrate 10.

[0031] A slit 74 is provided between the laser light source 71 and the galvanometer mirror 72. The area SA (see FIG. 4 ) of the spot area of ​​the laser light L is adjusted by adjusting the size of the opening of the slit 74. The area SA of the spot area means the area on the adhesive layer 2 of the laser light L that has passed through the transfer substrate 10 and been irradiated onto the adhesive layer 2.

[0032] The laser light irradiation unit 70 irradiates a laser beam L via a galvanometer mirror 72 and an fθ lens 73 onto a surface 10b (see FIG. 3) of the transfer substrate 10 held by the transfer substrate holding unit 30, the surface 10b being opposite to the surface 10a on which the semiconductor chip 1 is arranged. The laser beam L is irradiated toward the selected semiconductor chip 1 by the galvanometer mirror 72 and the fθ lens 73.

[0033] As shown in Fig. 4, the laser light irradiation unit 70, for example, intermittently irradiates the semiconductor chip 1 with laser light L. The control unit 60 controls the irradiation position of the laser light L so that the areas SA of the spot areas of the laser light L do not overlap each other. The area SA of the spot areas of the laser light L is smaller than the area 1A of the semiconductor chip 1. The semiconductor chip 1 has, for example, a rectangular shape, and the length of one side of the semiconductor chip 1 is not less than several tens of microns and not more than several millimeters. Furthermore, the spot area has, for example, a rectangular shape, and the length of one side of the spot area is not less than several microns and not more than several tens of microns.

[0034] (Semiconductor Chip Transfer Method) Next, the semiconductor chip transfer method of this embodiment will be described with reference to FIGS.

[0035] As shown in FIGS. 6( a) and 6(b), a semiconductor chip 1 is placed on a transfer substrate 10 by a device (not shown) or a user. In the process of placing the semiconductor chip on the transfer substrate, as shown in FIG. 6(a), a production substrate 80 on which a semiconductor chip 1, a sacrificial layer 4, and a resist 3 are arranged in this order is pressed against a transfer substrate 10 on which an adhesive layer 2 is arranged so that the resist 3 and the adhesive layer 2 come into contact. Then, as shown in FIG. 6(b), the semiconductor chip 1 is placed on the transfer substrate 10 by removing only the production substrate 80. Specifically, as shown in FIG. 6(a), the production substrate 80 is a substrate for manufacturing the semiconductor chip 1, and the semiconductor chip 1 is manufactured on the production substrate 80. The production substrate 80 and the semiconductor chip 1 are fixed by tether portions T of the resist 3. A space S is formed between the production substrate 80 and the semiconductor chip 1. The space S is formed by chemically removing a removal layer (not shown) formed during the manufacturing process of the semiconductor chip 1. 6B, when the production substrate 80 is removed, the tether portion T of the resist 3 is broken, thereby separating the production substrate 80 from the semiconductor chip 1, the sacrificial layer 4, and the resist 3. The production substrate 80 is made of, for example, InP.

[0036] After the process of placing the semiconductor chip on the transfer substrate, in step S1, as shown in FIG. 5, the control unit 60 irradiates the transfer substrate 10, on which the semiconductor chip 1 is placed, with laser light L from the side opposite to the surface 10a of the transfer substrate 10 on which the semiconductor chip 1 is placed (Z1 side) via the adhesive layer 2, resist 3, and sacrificial layer 4. Then, as the laser light L passes through the transfer substrate 10 and irradiates the adhesive layer 2, the sacrificial layer 4 and the semiconductor chip 1 are peeled off from the transfer substrate 10, and the sacrificial layer 4 and the semiconductor chip 1 are transferred from the transfer substrate 10 to the transfer substrate 20. In other words, transfer is performed using the laser lift-off method. An outline of step S1 is shown in FIG. 6(c) as the process of transferring the semiconductor chip to the transfer substrate. Here, in this embodiment, the adhesive force RR (see FIG. 7) between the adhesive layer 2 and the resist 3 is greater than the adhesive force RS (see FIG. 7) between the resist 3 and the sacrificial layer 4. As a result, the adhesive force RR (see FIG. 7) between the adhesive layer 2 and the resist 3 is greater than the adhesive force RS (see FIG. 7) between the resist 3 and the sacrificial layer 4, so that, as shown in FIG. 6(c), in the process of transferring the semiconductor chip to the transfer substrate, the resist 3 remains on the transfer substrate 10 side. For the sake of simplicity, FIGS. 6 and 9 show the semiconductor chip 1 as if it were transferred by a single laser beam, but in reality, as shown in FIG. 4, the entire semiconductor chip 1 is peeled off and transferred by intermittently irradiating it multiple times with laser beams having a spot area smaller than the area of ​​the semiconductor chip 1. The situation during the transfer of the semiconductor chip 1 will be described later.

[0037] In step S2, the control unit 60 determines whether all of the semiconductor chips 1 arranged on the transfer substrate 10 have been transferred. If the answer is No in step S2, the process returns to step S1. If the answer is Yes in step S2, the process of the semiconductor chip transfer method ends.

[0038] (Situation During Semiconductor Chip Transfer) In this embodiment, as shown in FIG. 7 , when the adhesive layer 2 is irradiated with laser light L, the adhesive layer 2 is deformed into a convex shape protruding toward the Z2 side. The resist 3 has a relatively large Young's modulus, and therefore deforms to follow the deformed adhesive layer 2. Furthermore, the resist 3 has a Young's modulus greater than the Young's modulus of the semiconductor chip 1 and the sacrificial layer 4. This results in a difference in the degree of deformation between the resist 3 and the semiconductor chip 1 and the sacrificial layer 4, resulting in a gap V being formed between the resist 3 and the sacrificial layer 4. Specifically, the degree of deformation of the semiconductor chip 1 and the sacrificial layer 4 is smaller than the degree of deformation of the resist 3. As a result, when the adhesive layer 2 and the resist 3 are deformed by irradiation with laser light L, the semiconductor chip 1 and the sacrificial layer 4 cannot follow the deformation of the adhesive layer 2 and the resist 3, and a reaction force is generated that causes them to return to their original shape. When this reaction force becomes greater than the adhesive force between the resist 3 and the sacrificial layer 4, the sacrificial layer 4 peels off from the resist 3. As a result, the semiconductor chip 1 and the sacrificial layer 4 are peeled off from the resist 3, forming a gap V between the resist 3 and the sacrificial layer 4. Here, the semiconductor chip 1 and the sacrificial layer 4 are in contact via a chemical bond, so the semiconductor chip 1 and the sacrificial layer 4 remain in contact when peeled off from the resist 3. The gap V reduces the overall adhesive force between the resist 3 and the sacrificial layer 4, thereby facilitating the peeling of the semiconductor chip 1 and the sacrificial layer 4 from the resist 3. The resist 3 remains on the transfer substrate 10 side. The thickness t2 of the adhesive layer 2 is, for example, several μm or more and 10 μm or less. The thickness t3 of the resist 3 is, for example, several μm or more and 10 μm or less. The combined thickness of the thickness t4 of the sacrificial layer 4 and the thickness t1 of the semiconductor chip 1 is, for example, 200 nm or more and 800 nm or less. The combined thickness of the thickness t4 of the sacrificial layer 4 and the thickness t1 of the semiconductor chip 1 is an example of the "thickness of the element" in the claims. The thickness t3 of the resist 3 is an example of the "thickness of the peeling layer" in the claims.

[0039] (Effect of the Relationship of Adhesion Force Between Layers on the Semiconductor Chip) Here, FIG. 7 in this embodiment shows the state of the semiconductor chip 1 when the adhesion force RR between the adhesive layer 2 and the resist 3 is greater than the adhesion force RS between the resist 3 and the sacrificial layer 4, while FIG. 8, a comparative example of this embodiment, shows the state of the semiconductor chip 1 when the adhesion force RR between the adhesive layer 2 and the resist 3 is equal to or less than the adhesion force RS between the resist 3 and the sacrificial layer 4. Here, the magnitudes of RR in FIGS. 7 and 8 are assumed to be equal. Distance D (see FIGS. 7 and 8) indicates the distance between blister B, which is a deformed portion of the adhesive layer 2 and the resist 3, and the boundary between the region where the resist 3 and the sacrificial layer 4 have peeled and the region where the resist 3 and the sacrificial layer 4 have not peeled. As shown in FIGS. 7 and 8, when the heights h of the blisters B are equal, the distance D in FIG. 7 is greater. The bending stress applied to the semiconductor chip 1 by the blister B is smaller in FIG. 7, where the distance D is greater, than in FIG. 8, where the distance D is smaller. 8, the bending stress applied to the semiconductor chip 1 by the blister B is large, so the semiconductor chip 1 is damaged in the area (area surrounded by the dashed line) where the bending stress of the semiconductor chip 1 is concentrated. Therefore, the semiconductor chip 1 is less likely to be damaged if the adhesive force RR between the adhesive layer 2 and the resist 3 is made larger than the adhesive force RS between the resist 3 and the sacrificial layer 4.

[0040] 8, even if the adhesive force RR between the adhesive layer 2 and the resist 3 is equal to or less than the adhesive force RS between the resist 3 and the sacrificial layer 4, reducing the output of the laser light L reduces the height h of the blister B and reduces the bending stress applied to the semiconductor chip 1. However, if the output of the laser light L is reduced too much, gas components are not generated in the adhesive layer 2, and blisters B are not generated. As a result, the semiconductor chip 1 is not transferred. In other words, making the adhesive force RR between the adhesive layer 2 and the resist 3 greater than the adhesive force RS between the resist 3 and the sacrificial layer 4 is effective in transferring the semiconductor chip 1 while suppressing damage to the semiconductor chip 1.

[0041] 9(a) and 9(b) show a process subsequent to the process of transferring the semiconductor chip 1 to the transfer substrate 20 in this embodiment. In the process subsequent to the process of transferring the semiconductor chip 1 to the transfer substrate 20, unnecessary portions are removed in order to mount only the semiconductor chip 1 on a circuit board (not shown). Specifically, as shown in FIG. 9(a), the adhesive layer between the chips is removed, for example, by plasma gas 90. Also, as shown in FIG. 9(b), the sacrificial layer is removed, for example, by immersing the semiconductor chip 1 in a cleaning solution 91. Here, if a resist 3 is transferred to the transfer substrate 20 when transferring the semiconductor chip 1 to the transfer substrate 20, unlike the case of FIG. 9, a process of removing the resist 3 from the transfer substrate 20 is required in the process subsequent to the process of transferring the semiconductor chip 1 to the transfer substrate 20. In other words, in this embodiment, the resist 3 remains on the transfer substrate 10, thereby eliminating the process of removing the resist 3 from the transfer substrate 20 in the process subsequent to the process of transferring the semiconductor chip 1 to the transfer substrate 20. That is, the fact that the resist 3 remains on the transfer substrate 10 side when the semiconductor chip 1 is transferred is effective in reducing the time required for the post-processing step of transferring the semiconductor chip 1 to the transfer substrate 20 .

[0042] (Effects of the embodiment) Next, effects of the embodiment will be described.

[0043] In this embodiment, as described above, the adhesive force RR between the adhesive layer 2 and the resist 3 is greater than the adhesive force RS between the resist 3 and the sacrificial layer 4 provided on the surface of the semiconductor chip 1 facing the resist 3, so that in the process of transferring the semiconductor chip to the transfer substrate, the resist 3 remains on the transfer substrate 10. This relatively small adhesive force RS between the resist 3 and the sacrificial layer 4 provided on the surface of the semiconductor chip 1 facing the resist 3 reduces the bending stress imparted to the sacrificial layer 4 and the semiconductor chip 1 by the resist 3 deformed due to deformation of the adhesive layer 2. This reduces damage to the semiconductor chip 1 even when the semiconductor chip 1 is relatively fragile, such as a semiconductor chip 1 with a relatively small thickness t1 + t4. As a result, a semiconductor chip transfer method can be provided that transfers the semiconductor chip 1 while suppressing damage to the semiconductor chip 1 due to deformation of the adhesive layer 2. Furthermore, since the resist 3 remains on the transfer substrate 10 side, the process of removing the resist 3 from the transfer substrate 20 is eliminated, unlike when the resist 3 is transferred to the transfer substrate 20, thereby reducing the time required for post-processing in the semiconductor chip transfer method.

[0044] Furthermore, in this embodiment, as described above, the process of placing the semiconductor chip on the transfer substrate includes a process of placing the semiconductor chip 1 on the transfer substrate 10 via the adhesive layer 2 and a release layer containing resist. Here, during the semiconductor chip manufacturing process, resist may be formed on the upper surface of the semiconductor chip (the surface of the semiconductor chip opposite the surface where the semiconductor chip faces the manufacturing substrate). Generally, the resist is transferred to the transfer substrate along with the semiconductor chip and is removed from the transfer substrate in a removal process subsequent to the semiconductor chip transfer method. Therefore, if the release layer is configured to contain resist, the resist 3 remains on the transfer substrate 10 during the process of transferring the semiconductor chip to the transfer substrate. As a result, the process of removing the resist 3 from the transfer substrate 20 is eliminated, thereby reducing the time required for subsequent processes in the semiconductor chip transfer method.

[0045] Furthermore, in this embodiment, as described above, the step of placing the semiconductor chip on the transfer substrate includes a step of placing the semiconductor chip 1 on the transfer substrate 10 via the adhesive layer 2 and the resist 3, which has a larger modulus of longitudinal elasticity than the semiconductor chip 1 and the sacrificial layer 4. As a result, the resist 3 has a larger modulus of longitudinal elasticity than the semiconductor chip 1 and the sacrificial layer 4, so the degree of deformation of the resist 3 is greater than the degree of deformation of the sacrificial layer 4 and the semiconductor chip 1. This can promote the peeling of the sacrificial layer 4 provided on the semiconductor chip 1. As a result, the semiconductor chip 1 can be easily peeled off.

[0046] Furthermore, in this embodiment, as described above, the process of transferring the semiconductor chip to the transfer substrate includes a process of transferring the semiconductor chip 1 while irradiating the resist 3 with laser light L to form a gap V between the resist 3 and the sacrificial layer 4 provided on the semiconductor chip 1 due to the difference in the degree of deformation caused by the difference in the Young's modulus between the resist 3 and the semiconductor chip 1 and the sacrificial layer 4. With this configuration, the gap V formed between the resist 3 and the sacrificial layer 4 provided on the semiconductor chip 1 reduces the overall adhesive force between the resist 3 and the sacrificial layer 4 provided on the semiconductor chip 1, thereby facilitating the peeling of the semiconductor chip 1 while leaving the resist 3 on the transfer substrate 10. As a result, by transferring the semiconductor chip 1 while forming the gap V between the resist 3 and the sacrificial layer 4 provided on the semiconductor chip 1, it is possible to more easily peel off only the semiconductor chip 1.

[0047] Furthermore, in this embodiment, as described above, the step of placing the semiconductor chip on the transfer substrate includes the step of placing the semiconductor chip 1, which has a thickness smaller than the thickness t3 of the resist 3, on the transfer substrate 10. In this way, even for a semiconductor chip 1 that is extremely thin, having a thickness smaller than the thickness t3 of the resist 3, making the adhesive force RS between the resist 3 and the sacrificial layer 4 provided on the semiconductor chip 1 relatively small is particularly effective in terms of suppressing damage to the semiconductor chip 1.

[0048] Furthermore, in this embodiment, as described above, the process of transferring a semiconductor chip to a transfer substrate includes a process of irradiating laser light L having a spot area smaller than the area 1A of the semiconductor chip 1. Here, when the power density of the laser light L is the same, the larger the area SA of the spot area, the greater the height h of the deformed portion (blister B) of the adhesive layer 2 and the resist 3. In other words, when the semiconductor chip 1 is transferred using laser light L having a spot area equal to or larger than the area of ​​the semiconductor chip 1, the relatively large height h of the deformed portion (blister B) of the adhesive layer 2 and the resist 3 increases the bending stress applied to the semiconductor chip 1, making the semiconductor chip 1 more susceptible to damage. Therefore, if the semiconductor chip 1 is transferred using laser light L having a spot area smaller than the area 1A of the semiconductor chip 1, the height h of the deformed portion (blister B) of the adhesive layer 2 and the resist 3 becomes relatively small, thereby reducing the bending stress applied to the semiconductor chip 1 and preventing damage to the semiconductor chip 1. As a result, the semiconductor chip 1 can be transferred while preventing damage to the semiconductor chip 1 due to deformation of the adhesive layer 2.

[0049] [Modifications] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications (modifications) within the meaning and scope of the claims.

[0050] For example, although the above embodiment shows an example in which a resist is used as the release layer of the present invention, the present invention is not limited to this. For example, the release layer may be formed of a material other than a resist.

[0051] In the above embodiment, the resist 3 has a modulus of longitudinal elasticity greater than those of the semiconductor chip 1 and the sacrificial layer 4, but the present invention is not limited to this. For example, the resist 3 may have a modulus of longitudinal elasticity equal to or less than those of the semiconductor chip 1 and the sacrificial layer 4.

[0052] In the above embodiment, the sacrificial layer 4 and the semiconductor chip 1 are transferred while forming a gap V between the resist 3 and the sacrificial layer 4 provided on the semiconductor chip 1 due to the difference in the degree of deformation caused by the difference between the Young's modulus of the resist 3 and the Young's modulus of the sacrificial layer 4 and the semiconductor chip 1. However, the present invention is not limited to this. For example, the gap V does not have to be formed between the resist 3 and the sacrificial layer 4 provided on the semiconductor chip 1.

[0053] In the above embodiment, the total thickness of the sacrificial layer 4 and the semiconductor chip 1 is smaller than the thickness of the resist 3. However, the present invention is not limited to this. For example, the total thickness of the sacrificial layer 4 and the semiconductor chip 1 may be equal to or greater than the thickness of the resist 3.

[0054] In the above embodiment, the sacrificial layer 4 is provided on the surface of the semiconductor chip 1 facing the resist 3, but the present invention is not limited to this. For example, as in the modified example shown in Fig. 10, the sacrificial layer 4 may not be provided on the surface of the semiconductor chip 1 facing the resist 3. In Fig. 10, the adhesive force RR between the adhesive layer 2 and the resist 3 is greater than the adhesive force RT between the resist 3 and the semiconductor chip 1.

[0055] In the above embodiment, the area SA of the spot region of the laser light is smaller than the area 1A of the semiconductor chip 1, but the present invention is not limited to this. For example, the area SA of the spot region of the laser light may be equal to or larger than the area 1A of the semiconductor chip 1.

[0056] In the above embodiment, the transfer substrate 10 has a circular shape and the transferee substrate 20 has a rectangular shape, but the present invention is not limited to this. For example, the shapes of the transfer substrate 10 and the transferee substrate 20 may both be circular or polygonal.

[0057] In the above embodiment, the intervals between the irradiation positions of the intermittently irradiated laser light L are uniform on the semiconductor chip 1, but the present invention is not limited to this. For example, the intervals between the irradiation positions of the intermittently irradiated laser light L may be adjusted to be different between the end side and the center side of the semiconductor chip 1.

[0058] In the above embodiment, the fabrication substrate 80 and the semiconductor chip 1 are fixed by the tether portion T of the resist 3, but the present invention is not limited to this. For example, the fabrication substrate 80 and the semiconductor chip 1 may be fixed by an adhesive instead of the tether portion T of the resist 3. When the fabrication substrate 80 and the semiconductor chip 1 are fixed by an adhesive, there is no space S between the fabrication substrate 80 and the semiconductor chip 1.

[0059] In the above embodiment, the spot area of ​​the laser light is rectangular, but the present invention is not limited to this. For example, the spot area of ​​the laser light may be circular.

[0060] In the above embodiment, an example was shown in which an element having a small thickness such as an InP chip was used as the semiconductor chip 1, but the present invention is not limited to this. For example, various semiconductor elements other than an InP chip may be used as the semiconductor chip 1.

[0061] In the above embodiment, the moving mechanism 50 is configured to be able to move both the transfer substrate holding part 30 and the transferee substrate holding part 40, but the present invention is not limited to this. For example, the moving mechanism 50 may be provided separately for the transfer substrate holding part 30 and the transferee substrate holding part 40.

[0062] DESCRIPTION OF SYMBOLS 1 Semiconductor chip (element) 1A Area of ​​semiconductor chip (area of ​​element) 2 Adhesive layer 3 Resist (peeling layer) 4 Sacrificial layer 10 Transfer substrate (first substrate) 10a Surface (surface on which element is arranged, surface on which element is arranged) 20 Transferred substrate (second substrate) 30 Transfer substrate holding unit (first substrate holding unit) 70 Laser light irradiation unit 100 Semiconductor chip transfer device (element transfer device) L Laser light SA Area of ​​spot region V Gap t1, t4 Thickness (thickness of element) t3 Thickness (thickness of release layer) RR Adhesion force (adhesion force between adhesive layer and release layer) RS, RT Adhesion force (adhesion force between release layer and element)

Claims

1. A method for transferring elements, comprising: an arrangement step of arranging an adhesive layer, a release layer and an element on a first substrate in that order; and a transfer step of irradiating laser light toward the first substrate from the side opposite to the surface on which the element is arranged on the first substrate, thereby transferring the element to a second substrate, wherein the adhesive force between the adhesive layer and the release layer is greater than the adhesive force between the release layer and the element, and wherein the release layer remains on the first substrate side during the transfer step.

2. The element transfer method according to claim 1, wherein the placement step includes a step of placing the element on the first substrate via the adhesive layer and the release layer containing a resist.

3. The element transfer method according to claim 1, wherein the placement step includes a step of placing the element on the first substrate via the adhesive layer and the release layer having a longitudinal elastic modulus greater than the longitudinal elastic modulus of the element.

4. The element transfer method according to claim 3, wherein the transfer step includes a step of transferring the element while forming a gap between the release layer and the element by irradiating the laser light due to a difference in the degree of deformation caused by a difference in the longitudinal elastic modulus between the release layer and the element.

5. The element transfer method according to claim 1, wherein the placing step includes a step of placing the element having a thickness smaller than a thickness of the release layer on the first substrate.

6. The element transferring method according to claim 1, wherein the transferring step includes a step of irradiating the laser light having a spot region having an area smaller than an area of ​​the element.

7. An element transfer device comprising: a first substrate holding section that holds a first substrate on which an adhesive layer, a peeling layer, and an element are arranged in that order; and a laser beam irradiation section that is arranged on the side of the first substrate opposite to the surface on which the element is arranged, and that irradiates laser beams toward the first substrate to transfer the element to a second substrate, wherein the adhesive force between the adhesive layer and the peeling layer is greater than the adhesive force between the peeling layer and the element, and the laser beam irradiation section is configured to transfer the element so that the peeling layer remains on the first substrate side.

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