Element transfer method and element transfer device

Abstract

Provided is an element transfer method capable of separating an element from an adhesion layer even when the element has a relatively small thickness and a low weight. Specifically, this semiconductor chip transfer method (element transfer method) comprises: a placement step for placing and laminating, on a transfer substrate 10, an adhesion layer 2, a resist layer 3, and a semiconductor chip 1 in the stated order in a manner that allows mutual attachment; and a transfer step for emitting laser light L toward the transfer substrate 10 from the side reverse to the surface, of the transfer substrate 10, on which the semiconductor chip 1 is placed and deforming the adhesion layer 2 to thereby transfer the semiconductor chip 1 to a transfer-receiving substrate 20. In the transfer step, the adhesion layer 2 and the semiconductor chip 1 are separated as a result of destruction of the resist layer 3 caused by the deformation of the adhesion layer 2.

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] The above-mentioned Patent Document 1 discloses a laser transfer method for transferring an article attached to a substrate to another substrate. In the above-mentioned Patent Document 1, a release layer is provided between the substrate and the article, the release layer including a blistering layer that deforms when irradiated with laser light and an adhesive layer laminated on the blistering layer, and the article is held by the adhesive layer. In the above-mentioned Patent Document 1, laser light is irradiated from the upper surface side of the substrate toward the blistering layer laminated on 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 separated from the release 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, the weight of the article (element) is relatively small, so that the deformed portion of the release layer (adhesive layer) and the element remain attached to each other during transfer and are not separated, and the element may not be transferred to another substrate. For this reason, there is a demand for an element transfer method and an element transfer device that can separate the element from the adhesive layer even when the thickness of the element is relatively small.

[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 separating an element from an adhesive layer even when the element is relatively thin and has a light weight.

[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 stacking and arranging an adhesive layer, a destructive layer, and an element on a first substrate in this order so that they adhere to each other, 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 deforming the adhesive layer and transferring the element to a second substrate, wherein in the transfer step, the destructive layer is destroyed due to the deformation of the adhesive layer, thereby separating the adhesive layer and the element.

[0008] In the element transfer method according to the first aspect, as described above, the destructive layer is destroyed due to deformation of the adhesive layer during the transfer process, thereby separating the adhesive layer from the element. As a result, the area of ​​the adhesion region between the destructive layer and the element during transfer is reduced by the destruction of the destructive layer. Therefore, the adhesive force between the destructive layer attached to the adhesive layer during transfer and the element can be reduced, so that an element transfer method can be provided that can separate the element from the adhesive layer even when the element is relatively thin and has a small weight.

[0009] In the element transfer method according to the first aspect, the destructible layer preferably has a ductility smaller than that of the adhesive layer. With this configuration, the destructible layer is destroyed without being able to follow the deformation of the adhesive layer during transfer, so that the destructible layer can be easily destroyed.

[0010] In the element transfer method according to the first aspect, the destruction layer preferably includes a resist layer. This configuration allows the resist layer, which is formed as a protective film (mask) when processing (patterning) a substrate in the element manufacturing process, to be used as the destruction layer, eliminating the need for a new destruction layer. This simplifies the element transfer process.

[0011] An element transfer device according to a second aspect of the present invention comprises a first substrate holding unit that holds a first substrate having an adhesive layer, a destructive layer, and an element stacked and arranged so that they adhere to each other in this order, and a laser light irradiation unit that irradiates laser light toward the first substrate from the side opposite to the surface on which the element is arranged on the first substrate, thereby deforming the adhesive layer and transferring the element to the second substrate, and the laser light irradiation unit is configured to irradiate laser light so as to destroy the destructive layer due to the deformation of the adhesive layer, thereby separating the adhesive layer and the element.

[0012] In the device transfer device according to the second aspect, as described above, the laser light irradiation unit is configured to irradiate the laser light so as to destroy the destructive layer due to deformation of the adhesive layer, thereby separating the adhesive layer and the device. By destroying the destructive layer, the area of ​​the adhesion region between the destructive layer and the device during transfer is reduced. Therefore, the adhesive force between the destructive layer attached to the adhesive layer during transfer and the device can be reduced, so that a device transfer device can be provided that can separate the device from the adhesive layer even when the device is relatively thin and has a small weight.

[0013] As described above, the element transfer method and element transfer apparatus of the present invention can separate an element from an adhesive layer even when the element is relatively thin and has a small weight.

[0014] Fig. 1 is a schematic diagram showing the overall configuration of a semiconductor chip transfer device according to one embodiment of the present invention; Fig. 2 is a plan view showing a state in which a semiconductor chip according to one embodiment of the present invention is placed on a transfer substrate; Fig. 3 is a cross-sectional view of a semiconductor chip transfer device during transfer according to one embodiment of the present invention; Fig. 4 is a diagram for explaining a spot area of ​​laser light according to one embodiment of the present invention; Fig. 5 is a flowchart for explaining processing of a semiconductor chip transfer method according to one embodiment of the present invention; Fig. 6 is a schematic diagram for explaining steps of a semiconductor chip transfer method according to one embodiment of the present invention; Fig. 7 is a diagram showing the state of a semiconductor chip during transfer according to one embodiment of the present invention.

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings.

[0016] (Configuration of Semiconductor Chip Transfer Apparatus) The configuration of a semiconductor chip transfer apparatus 100 according to this embodiment 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.

[0017] 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.

[0018] 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.

[0019] 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, for example, a circular shape. The semiconductor chip 1 is, for example, a thin element such as an InP chip that is rectangular with a side length of several tens of μm to several mm and has a thickness of 200 nm to 800 nm.

[0020] As shown in Figure 3, the semiconductor chip 1 is placed on a transfer substrate 10 via an adhesive layer 2 and a resist layer 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 resist layer 3 is an example of a "destruction layer" in the claims. The semiconductor chip 1 is an example of an "element" in the claims. The adhesive layer 2 is also called a transfer material and a release material.

[0021] The adhesive layer 2 is disposed on the surface 10a of the transfer substrate 10 opposite the side irradiated with the laser light L (Z2 side). The adhesive layer 2 is formed from a material that decomposes and generates gas components when irradiated with the laser light L from the laser light irradiating unit 70. The generation of the gas components causes the adhesive layer 2 to deform into a convex shape (see FIG. 7) that protrudes toward the side opposite the side irradiated with the laser light L (Z2 side). The adhesive layer 2 is formed from, for example, polyimide or silicon.

[0022] The resist layer 3 is disposed on a surface 2a of the adhesive layer 2 opposite the transfer substrate 10 (Z2 side). The resist layer 3 is formed as a protective film (mask) when processing (patterning) the substrate in the manufacturing process of the semiconductor chip 1. In this embodiment, the resist layer 3 has a ductility less than that of the adhesive layer 2. The resist layer 3 has the property of being destroyed when deformed beyond a predetermined degree. For example, "MICROPOSIT S1813 PHOTO RESIST" is used as the resist layer 3. The semiconductor chip 1 is disposed on a surface 3a of the resist layer 3 opposite the adhesive layer 2 (Z2 side).

[0023] 1 and 3, the transfer substrate holding unit 30 holds a transfer substrate 10 on which a semiconductor chip 1 is arranged via an adhesive layer 2 and a resist layer 3. 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 (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 direction and Y direction by a movement mechanism 50.

[0024] 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, in order to manufacture a semiconductor product. An adhesive layer 21 is arranged on the transfer substrate 20 to adhere the transferred semiconductor chips 1. 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, for example, a rectangular shape.

[0025] 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. By performing one or both of the movement of the transfer substrate holding unit 30 and the movement of 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.

[0026] 1, the control unit 60 is configured with a processor such as a CPU (Central Processing Unit), and performs various controls by executing a program (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 controls the operation of the moving mechanism 50 and the operation of the laser light irradiation unit 70.

[0027] 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, an fθ lens 73, and a slit 74. The laser light source 71 is a light source that emits laser light L. The galvanometer mirror 72 is composed of two mirrors, each of which is independently 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.

[0028] A slit 74 is provided between the laser light source 71 and the galvanometer mirror 72. The area of ​​a spot region LS (see FIG. 4 ) of the laser light L is adjusted by adjusting the size of the opening of the slit 74. The spot region LS refers to an irradiated region 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.

[0029] 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.

[0030] 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 spot areas LS of the laser light L do not overlap each other. The area of ​​the spot areas LS of the laser light L is smaller than the entire area 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.

[0031] (Semiconductor Chip Transfer Method) Next, the semiconductor chip transfer method of this embodiment will be described with reference to FIGS.

[0032] As shown in the placement process 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 placement process, as shown in FIG. 6(a), a production substrate 80 on which a semiconductor chip 1 and a resist layer 3 are placed in this order is pressed against a transfer substrate 10 on which an adhesive layer 2 is placed so that the resist layer 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. Here, 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 the tether portion 3b of the resist layer 3. A space 4 is formed between the production substrate 80 and the semiconductor chip 1. The space 4 is formed by chemically removing a removal layer (not shown) formed in the manufacturing process of the semiconductor chip 1. 6(b), when the production substrate 80 is removed, the tether portions 3b of the resist layer 3 are broken, thereby separating the production substrate 80 from the semiconductor chip 1 and resist layer 3, thereby completing the placement process. That is, in this embodiment, in the placement process, the adhesive layer 2, the resist layer 3, and the semiconductor chip 1 are stacked and placed on the transfer substrate 10 in this order so that they adhere to each other. The production substrate 80 is made of, for example, InP.

[0033] After the step of placing the semiconductor chip 1 on the transfer substrate 10, the process of the semiconductor chip transfer method is performed as shown in FIG. 3 , 5 , and 6 . In step S1, the control unit 60 (see FIG. 1 ) irradiates the transfer substrate 10, on which the semiconductor chip 1 is placed, with laser light L from the side (Z1 side) opposite the surface 10a of the transfer substrate 10 on which the semiconductor chip 1 is placed, via the adhesive layer 2 and the resist layer 3. The laser light L then passes through the transfer substrate 10 and irradiates the adhesive layer 2, thereby peeling the semiconductor chip 1 from the transfer substrate 10 and transferring the semiconductor chip 1 from the transfer substrate 10 to the transferee substrate 20. That is, transfer is performed by the laser lift-off method. In other words, in this embodiment, in the transfer step, the laser light L is irradiated toward the transfer substrate 10 from the side opposite the surface on which the semiconductor chip 1 is placed on the transfer substrate 10, thereby deforming the adhesive layer 2 and transferring the semiconductor chip 1 to the transferee substrate 20.

[0034] An outline of step S1 is shown in the transfer process in Figure 6(c). Here, in this embodiment, in the transfer process, the resist layer 3 is destroyed due to deformation of the adhesive layer 2, and the adhesive layer 2 and the semiconductor chip 1 are separated. The situation during the transfer of the semiconductor chip 1 will be described later. Note that in Figure 6, for the sake of simplicity, the semiconductor chip 1 is illustrated as being transferred by a single laser beam L. In reality, however, as shown in Figure 4, the entire semiconductor chip 1 is separated and transferred by intermittently irradiating the laser beam L having a spot area smaller than the area of ​​the semiconductor chip 1 multiple times.

[0035] 5, in step S2, the control unit 60 (see FIG. 1) 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 (if all of the semiconductor chips 1 arranged on the transfer substrate 10 have not been transferred), the process returns to step S1 and continues the transfer process. If the answer is Yes in step S2 (if all of the semiconductor chips 1 arranged on the transfer substrate 10 have been transferred), the process of the semiconductor chip transfer method ends.

[0036] (Situation During Transfer of Semiconductor Chip) Next, with reference to FIG. 7, the situation during transfer of the semiconductor chip 1 of this embodiment will be described.

[0037] 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 that protrudes toward the side opposite to the side irradiated with the laser light L (the Z2 side). The resist layer 3 is then deformed by the deformed adhesive layer 2. As described above, since the resist layer 3 has less ductility than the adhesive layer 2, the entire portion of the resist layer 3 corresponding to the deformed adhesive layer 2 is destroyed without being able to follow the deformation of the adhesive layer 2. The destruction of the resist layer 3 reduces the area of ​​adhesion between the resist layer 3 and the semiconductor chip 1, and the semiconductor chip 1 separates from the resist layer 3 (adhesive layer 2) due to its own weight. Furthermore, fragments 3c of the resist layer 3 adhere to the portion of the semiconductor chip 1 corresponding to the destroyed resist layer 3 after transfer. In other words, in this embodiment, during the transfer process, the resist layer 3 is destroyed (cracked) due to the deformation of the adhesive layer 2 when separated from the semiconductor chip 1, and is divided into a portion that adheres to the adhesive layer 2 and a portion that adheres to the semiconductor chip 1. In this embodiment, if even one crack occurs in the resist layer 3, the resist layer 3 is considered to be destroyed.

[0038] In this embodiment, the resist layer 3 is configured so as not to have adhesive force to the semiconductor chip 1 once it is separated from the semiconductor chip 1 .

[0039] (Effects of the embodiment) Next, the effects of the present embodiment will be described.

[0040] In this embodiment, as described above, in the transfer step, the resist layer 3 is destroyed due to deformation of the adhesive layer 2, thereby separating the adhesive layer 2 from the semiconductor chip 1. As a result, the resist layer 3 is destroyed, and the area of ​​the adhesion region between the resist layer 3 and the semiconductor chip 1 during transfer is almost eliminated. Therefore, there is almost no adhesion force between the resist layer 3 attached to the adhesive layer 2 during transfer and the semiconductor chip 1, so it is possible to provide an element transfer method that can separate the semiconductor chip 1 from the adhesive layer 2 even when the semiconductor chip 1 is relatively thin and has a small weight.

[0041] Furthermore, in this embodiment, as described above, the resist layer 3 has a ductility smaller than that of the adhesive layer 2. As a result, during transfer, the resist layer 3 cannot follow the deformation of the adhesive layer 2 and is destroyed, so that the resist layer 3 can be easily destroyed.

[0042] In this embodiment, as described above, the resist layer 3 is used as the destructive layer. This allows the resist layer 3, which is formed as a protective film (mask) when processing (patterning) the substrate in the manufacturing process of the semiconductor chip 1, to also be used as the destructive layer, thereby eliminating the process of forming a new layer to be used as the destructive layer. This simplifies the element transfer process.

[0043] [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.

[0044] For example, in the above embodiment, a resist layer is used as the destructible layer of the present invention, but the present invention is not limited to this. For example, the destructible layer may be formed of a material other than a resist layer.

[0045] In the above embodiment, the laser light L is irradiated onto the semiconductor chip 1 so that the spot areas LS of the laser light L do not overlap each other, but the present invention is not limited to this. For example, the laser light L may be irradiated onto the semiconductor chip 1 so that the spot areas LS of the laser light L overlap each other.

[0046] In the above embodiment, fragments 3c of the resist layer 3 are attached to the portions of the semiconductor chip 1 corresponding to the portions where the resist layer 3 is destroyed after transfer, but the present invention is not limited to this. For example, the fragments 3c of the resist layer 3 may not be attached to the semiconductor chip 1 after transfer.

[0047] In the above embodiment, the area of ​​the spot region LS of the laser light L is smaller than the area of ​​the semiconductor chip 1, but the present invention is not limited to this. For example, the area of ​​the spot region LS of the laser light L may be equal to or larger than the area of ​​the semiconductor chip 1.

[0048] 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.

[0049] In the above embodiment, the manufacturing substrate 80 and the semiconductor chip 1 are fixed to each other by the tether portions 3b of the resist layer 3, but the present invention is not limited to this. For example, the manufacturing substrate 80 and the semiconductor chip 1 may be fixed to each other by an adhesive or the like instead of the tether portions 3b of the resist layer 3.

[0050] In the above embodiment, the spot area LS of the laser light L has a rectangular shape, but the present invention is not limited to this. For example, the spot area LS of the laser light L may have a circular shape.

[0051] 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.

[0052] 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.

[0053] In the above embodiment, the resist layer 3 is destroyed to almost completely eliminate the area of ​​the adhesion region between the resist layer 3 and the semiconductor chip 1, but the present invention is not limited to this. For example, the area of ​​the adhesion region between the resist layer 3 and the semiconductor chip 1 due to the destruction of the resist layer 3 may be small enough that the semiconductor chip 1 can be separated from the resist layer 3 (adhesive layer 2) by its own weight.

[0054] REFERENCE SIGNS LIST 1 semiconductor chip (element) 2 adhesive layer 3 resist layer (destructible layer) 10 transfer substrate (first substrate) 10a surface (surface on which elements are arranged, surface on which elements are arranged) 20 transferee 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

Claims

1. A device transfer method comprising: an arrangement step of laminating and arranging an adhesive layer, a destructible layer, and an element on a first substrate in this order so that they adhere to one another; and a transfer step of irradiating a laser beam toward the first substrate from the side opposite to the surface on which the element is arranged on the first substrate, thereby deforming the adhesive layer and transferring the element to a second substrate, wherein in the transfer step, the destructible layer is destroyed due to the deformation of the adhesive layer, thereby separating the adhesive layer and the element.

2. The element transfer method according to claim 1, wherein the destructive layer has a ductility less than that of the adhesive layer.

3. The element transfer method according to claim 1, wherein the destructive layer includes a resist layer.

4. An element transfer device comprising: a first substrate holding unit that holds a first substrate having an adhesive layer, a destructive layer, and an element stacked and arranged so that they adhere to each other in this order; and a laser light irradiation unit that irradiates laser light toward the first substrate from the side opposite to the surface on which the element is arranged on the first substrate, thereby deforming the adhesive layer and transferring the element to a second substrate, wherein the laser light irradiation unit is configured to irradiate the laser light so that the destructive layer is destroyed due to the deformation of the adhesive layer, thereby separating the adhesive layer and the element.

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