Method for partial removal of retaining layer, and apparatus for partial removal of retaining layer

Abstract

To provide a holding layer partial removal method and a holding layer partial removal device that allow a holding layer to come into contact with an element only in a region which is of the same size with a second principal surface of the element or the size of the second principal surface of the element inside.SOLUTION: A holding layer partial removal method of a holding layer partial removal device comprises removing a part of a holding layer 10 on a substrate 20 which holds a second principal surface 1B of a semiconductor chip across the holding layer 10, and includes a holding layer removal process of removing the part of the holding layer 10 by irradiating the semiconductor chip with laser light 111 from the side of a first principal surface 1A of the semiconductor chip so that the entire arrangement range area of the holding layer 10 in an array region of the semiconductor chip 1 is an irradiation range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for partially removing a holding layer that adhesively holds elements such as semiconductor chips on a substrate, and a device for partially removing the holding layer.

Background Art

[0002] Semiconductor chips are miniaturized for cost reduction, and in particular, efforts are being made to mount miniaturized semiconductor chips, especially LED chips, at high speed and with high precision. In particular, LEDs used in displays are required to mount LED chips of 50 μm × 50 μm or less, called micro LEDs, at high speed with an accuracy of several μm.

[0003] Patent Document 1 describes that in a case where a semiconductor chip held on a substrate via a holding layer is transferred by laser lift-off, the holding layer contacts the semiconductor chip only in a region equivalent to or inside the surface of the semiconductor chip closest to the holding layer, so that the holding layer does not wrap around the side surface of the semiconductor chip, and the semiconductor chip can be accurately transferred without tilting during laser lift-off.

Prior Art Documents

Patent Documents

[0004] Patent Document 1: WO2020 / 166301

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the method described in Patent Document 1 has a problem that there is no description and it is unclear about the method of making the holding layer contact the semiconductor chip only in a region equivalent to or inside the surface of the semiconductor chip closest to the holding layer.

[0006] The present invention aims to solve the above problems and disclose a method and apparatus for causing an element such as a semiconductor chip to contact a retaining layer only in a region of the same size as the element or in a region inside the element. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a method for partially removing a retaining layer in a substrate in which a second main surface of an element is held via a retaining layer, wherein a portion of the retaining layer is removed. In the array region of the aforementioned elements Including the entire first principal surface of the element The present invention provides a method for partially removing a retaining layer, characterized by performing a retaining layer removal step in which a laser is irradiated from the first main surface side of the element so that the entire area of ​​the retaining layer arrangement becomes the irradiation area, thereby removing a part of the retaining layer.

[0008] This configuration ensures that elements such as semiconductor chips contact the retaining layer only in areas of the same size as the element or areas inside the element, preventing the retaining layer from wrapping around the sides of the element. This prevents the semiconductor chip from tilting during laser lift-off, allowing for accurate transfer.

[0009] A method for partially removing a retaining layer, wherein the laser spot irradiated in the retaining layer removal step is sized to include at least the entire first main surface of at least one element and the retaining layer surrounding the element, and the laser having the laser spot is moved relative to the element to irradiate the entire area of ​​the retaining layer arrangement in the element arrangement region.

[0010] This configuration allows for the removal of the retaining layer around the element, ensuring that the retaining layer does not wrap around the sides of the element, and enabling accurate transfer without the element tilting due to laser lift-off during the transfer process.

[0011] A method for partially removing a retaining layer, wherein the laser spot irradiated in the retaining layer removal step is linear, and the laser spot is moved relative to the linear laser spot in a direction perpendicular to the length direction of the laser spot, so that the entire area of ​​the retaining layer arrangement in the element arrangement region is irradiated with the laser.

[0012] With this configuration, by irradiating the entire first main surface of the element and the retaining layer surrounding the element with a laser, the retaining layer around the element can be removed, ensuring that the retaining layer does not wrap around to the side of the element, and the semiconductor chip does not tilt during laser lift-off, allowing for accurate transfer.

[0013] Furthermore, in order to solve the above problems, the present invention provides a retaining layer partial removal device for a substrate in which a second main surface of an element is held via a retaining layer, wherein a part of the retaining layer is removed. A laser irradiation unit that emits laser light, A substrate holding portion for holding the substrate, While irradiating the element with laser light from the laser irradiation unit from the first main surface side, the unit is moved relative to the substrate holding unit, in the array region of the element. Including the entire first principal surface of the element The present invention provides a retaining layer partial removal device, characterized by comprising a control unit that controls the entire area of ​​the retaining layer to become a laser irradiation area.

[0014] This configuration ensures that the element contacts the retaining layer only in an area of ​​the same size as the element or an area inside the element, preventing the retaining layer from wrapping around the side of the element. This prevents the semiconductor chip from tilting during laser lift-off, allowing for accurate transfer. [Effects of the Invention]

[0015] The present invention's method or apparatus for partially removing a retaining layer makes it possible to ensure that an element such as a semiconductor chip contacts the retaining layer only in an area of ​​the same size as the element or in an area inside the element. [Brief explanation of the drawing]

[0016] [Figure 1] This is a diagram for explaining a partial removal device for a holding layer in Example 1 of the present invention. [Figure 2] This is a diagram for explaining a partial removal method for a holding layer in Example 1 of the present invention. [Figure 3] This is a diagram for explaining a holding layer around an element in Example 1 of the present invention. [Figure 4] This is a diagram for explaining conventional problems. [Figure 5] This is a diagram for explaining a partial removal device for a holding layer in Example 2 of the present invention. [Figure 6] This is a diagram for explaining a partial removal method for a holding layer in Example 2 of the present invention. [[ID=二十二]]

Mode for Carrying Out the Invention

Example

[0017] Example 1 of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a diagram for explaining a partial removal device for a holding layer in Example 1 of the present invention. FIG. 2 is a diagram for explaining a partial removal method for a holding layer in Example 1 of the present invention, where (a) shows the substrate before laser irradiation and (b) shows the substrate after laser irradiation. FIG. 3 is a diagram for explaining a holding layer around an element in Example 1 of the present invention. FIG. 4 is a diagram for explaining conventional problems.

[0018] (Partial removal device for holding layer) The partial removal device 100 for a holding layer in Example 1 has a holding layer removal unit 110. And the holding layer removal process described later is performed by the holding layer removal unit 110.

[0019] Details of the holding layer removal unit 110 are shown in FIG. 1. The holding layer removal unit 110 includes a laser irradiation unit 112 that irradiates laser light 111, a substrate holding unit 114 that holds the substrate 2 and is movable at least in the X-axis direction and the Y-axis direction, and a control unit (not shown).

[0020] The laser irradiation unit 112 is a device that irradiates laser light 111, such as an excimer laser, and is fixedly installed on the retaining layer removal unit 110. In Example 1, the laser irradiation unit 112 irradiates laser light 111 with a wavelength of 266 nm in a substantially rectangular spot shape. The irradiation position of the laser light 111 in the X-axis and Y-axis directions is controlled by the control unit via a galvanometer mirror 115 and an fθ lens 116 whose angles are adjusted, and selectively irradiates the retaining layer 10 on the substrate 20 held by the substrate holding unit 114. Since the laser light 111 in Example 1 has a wavelength of 266 nm, the laser light irradiated onto the first main surface 1A of the semiconductor chip 1 (element) is absorbed by GaN and blocked, and does not reach the retaining layer to which the semiconductor chip 1 is in contact and adhesively held. On the other hand, when the laser light 111 is incident on the retaining layer 20 where the semiconductor chip 1 is not placed, the retaining layer 10 in the incident area is removed along with the generation of gas. As a result, a portion of the retaining layer 10 on the substrate 20 is removed.

[0021] In Example 1, the laser irradiation unit 112 irradiates the substrate 20 with a laser spot 50 that is large enough to include at least the entire area of ​​one semiconductor chip 1 arranged in the X and Y directions, and the exposed retaining layer around the semiconductor chip.

[0022] Furthermore, the substrate holding portion 114 moves at least in the X-axis direction and the Y-axis direction by a moving mechanism (not shown). The control unit controls this moving mechanism and adjusts the position of the substrate holding portion 114, thereby adjusting the relative position of the semiconductor chip 1 held on the substrate with respect to the substrate.

[0023] The substrate holding portion 114 has a flat surface on its upper surface and holds the substrate 20 during the retaining layer removal process described later. Multiple suction holes are provided on the upper surface of the substrate holding portion 114, and the second main surface 22 of the substrate (the surface without the retaining layer) is held by suction force.

[0024] In Example 1, the substrate holding portion 114 moves in both the X-axis and Y-axis directions, but this is not necessarily limited to this configuration and can be modified as appropriate. For example, it may move in only one of the X-axis or Y-axis directions. Alternatively, the substrate holding portion may not move in any direction, and the laser beam may move instead.

[0025] In Example 1, a roughly rectangular laser spot was used, but this is not necessarily the only option and can be modified as appropriate. For example, a roughly circular or elliptical laser spot may be used.

[0026] Furthermore, although the wavelength of the laser light was set to 266 nm in Example 1, it is not necessarily limited to this and can be changed as appropriate. For example, other wavelengths may be used, as long as they do not penetrate the semiconductor chip 1.

[0027] (Method for partial removal of the retaining layer) The method for partial removal of the retaining layer in Example 1 will be described below. As shown in Figure 2(a), a retaining layer 10 is provided over almost the entire surface of the first main surface 21 of the substrate 20, and the second main surface 1B of the semiconductor chip 1 is in contact with the side of the retaining layer 10 opposite to the substrate 20, with 7 chips arranged in the X direction and 5 chips in the Y direction, and held in place by adhesive. In Example 1, the semiconductor chips arranged in the X direction are designated a, b, c...g from left to right when viewed from the first main surface side of the substrate 20, and the semiconductor chips arranged in the Y direction are designated 1, 2, 3, 4, 5, with the upper left semiconductor chip being designated 1a.

[0028] The retaining layer removal process is performed by irradiating the retaining layer 10 with laser light 111 having a laser spot 50 from the first main surface 1A side of the semiconductor chip 1a. The laser spot 50 is sized to include the entire first main surface 1A of the semiconductor chip 1, and the retaining layer 16a (see Figure 3) exposed in a rectangular ring shape around the semiconductor chip 1.

[0029] In Example 1, the laser was irradiated with a laser spot 50 large enough to include at least the entire first main surface 1A of one semiconductor chip 1 and the retaining layer 16a exposed in a rectangular ring shape around the semiconductor chip 1. However, this is not necessarily limited to this and can be modified as appropriate. For example, the laser may be irradiated with a laser spot large enough to include the entire first main surface of multiple semiconductor chips 1 and the retaining layer around them. Here, the retaining layer around the semiconductor chip refers to the retaining layer in an area where, if removed, there is no risk of the retaining layer spreading to the side surface of the semiconductor chip.

[0030] When the laser beam 111 is irradiated with a laser spot 50 in size onto a region centered on the semiconductor chip 1a, the retaining layer 16a exposed around the semiconductor chip as shown in Figure 3 is removed by ablation along with the generation of gas. The laser beam 111 irradiated onto the entire first main surface 1A of the semiconductor chip 1a is blocked by the semiconductor chip 1a, so the laser beam 111 does not strike the retaining layer on the second main surface 1B side of the semiconductor chip 1a, and ablation does not occur there. However, a portion of the retaining layer around the second main surface 1B side of the semiconductor chip 1a may be ablated due to the angle and refraction of the laser beam 111, and may be removed along with the generation of gas.

[0031] As a result, as shown in Figure 2(b), the retaining layer that adheres to the semiconductor chip 1 (for example, semiconductor chips 1a to 1g) will be an area equivalent to or smaller than the size of the second main surface of the semiconductor chip 1. In other words, the retaining layer does not wrap around the sides of the semiconductor chip 1. Therefore, as will be described later, the semiconductor chip 1 can be transferred with high precision without tilting during the transfer process.

[0032] Conventionally, as shown in Figure 4(a), if there is a wrap-around retaining layer 19 where the retaining layer 10 wraps around the side surface of the semiconductor chip 1, when transferring by laser lift-off by irradiating laser light from the second main surface 1B side of the semiconductor chip 1, there is a problem that the semiconductor chip 1 is tilted by the wrap-around retaining layer 19 and transferred to the substrate 30, as shown in Figure 4(b). However, with the retaining layer removal process in Embodiment 1 of the present invention, the wrap-around retaining layer 19 is not formed, and transfer can be performed with high precision.

[0033] Next, the entire semiconductor chip 1b and its surroundings are irradiated with laser light 111, and a retaining layer removal process is performed on the retaining layer exposed in a rectangular ring shape around the semiconductor chip 1b and on a portion of the retaining layer on the second main surface side of the semiconductor chip 1b. Furthermore, the retaining layer removal process is performed sequentially on semiconductor chips 1c, 1d, 1e, 1f, and 1g in the same manner.

[0034] Once the retaining layer removal process for the first row of semiconductor chips 1a to 1g is complete, the substrate holding unit 114 is moved while the retaining layer removal process is carried out for the second row of semiconductor chips 2a to 2g, then the third row of semiconductor chips 3a to 3g, the fourth row of semiconductor chips 4a to 4g, and the fifth row of semiconductor chips 5a to 5g, so that the retaining layer 10 adhering to all semiconductor chips 1 is the same size as or smaller than the size of the semiconductor chip 1, and any retaining layer that may wrap around to the sides is eliminated.

[0035] In Example 1, the retaining layer removal process was performed on the semiconductor chips 2a to 2g in the second row, followed by the semiconductor chips 3a to 3g in the third row, 4a to 4g in the fourth row, and 5a to 5g in the fifth row. However, this is not necessarily limited to this order and can be changed as appropriate. For example, the retaining layer removal process could be performed on the semiconductor chips 1b to 5b in the second row, followed by the semiconductor chips 1c to 5c in the third row, 1d to 5d in the fourth row, 1e to 5e in the fifth row, 1f to 5f in the sixth row, and 1g to 5g in the seventh row. The order is not important as long as the retaining layer removal process can be performed on all semiconductor chips.

[0036] As described above, a retaining layer removal process can be performed by irradiating the entire area of ​​the retaining layer 10 in the array region of the semiconductor chip with a laser so that the irradiation area covers the entire area of ​​the retaining layer 10, thereby removing a portion of the retaining layer 10. Here, the entire area of ​​the retaining layer 10 in the array region of the semiconductor chip refers to the entire area of ​​the retaining layer 10 that may wrap around to the side of the semiconductor chip, and does not include the area of ​​the retaining layer 10 that does not pose a risk of wrapping around to the side of the semiconductor chip.

[0037] By performing a retention layer removal process on all semiconductor chips, the retention layer 10 that provides adhesive retention becomes an area equivalent to or smaller than the size of the second main surface of the semiconductor chip. This allows for high-precision transfer of the semiconductor chip 1, which is adhesively held to the substrate 20, without tilting.

[0038] The retaining layer partial removal device 100 in Example 1 can also function as a laser lift-off device. In this case, after performing the retaining layer partial removal method to leave only a retaining layer 10 in an area equivalent to or smaller than the element (semiconductor chip 1) that holds the element, the remaining retaining layer 10 is removed by irradiating the second main surface side 22 of the translucent substrate 20 with laser light 111 from the laser irradiation unit 112. At the same time, the element is biased by the gas. In other words, laser lift-off is performed.

[0039] In Example 1, the element was a semiconductor chip, but it is not necessarily limited to this and can be changed as appropriate. For example, it can be an electronic component such as a resistor or capacitor, or a material such as a metal piece. Also, the retaining layer was made adhesive, but it is not necessarily limited to this and can be changed as appropriate. For example, a non-adhesive retaining layer may be used.

[0040] Thus, in Example 1, a method for partially removing a retaining layer is provided for a substrate in which the second main surface of an element is held via a retaining layer. This method is characterized by performing a retaining layer removal step in which a laser is irradiated from the first main surface side of the element so that the entire arrangement range of the retaining layer in the element's array region becomes the irradiation range, thereby removing a portion of the retaining layer. As a result, the retaining layer becomes the same size as or smaller than the second main surface of the element, the retaining layer does not wrap around the side of the element, and the element does not tilt during laser lift-off, allowing for accurate transfer.

[0041] Furthermore, in a substrate in which the second main surface of an element is held via a retaining layer, a retaining layer partial removal apparatus for removing a portion of the retaining layer, A laser irradiation unit that emits laser light, A substrate holding portion for holding the substrate, A partial retention layer removal device is characterized by comprising: a control unit that moves relative to the substrate holding unit while irradiating laser light from the laser irradiation unit from the first main surface side of the element, and controls the unit so that the entire arrangement range of the retention layer in the element arrangement region becomes the laser irradiation range. As a result, the retention layer becomes the same size as or smaller than the size of the second main surface of the element, the retention layer does not wrap around the side of the element, and the element does not tilt during laser lift-off, allowing for accurate transfer. [Examples]

[0042] Embodiment 2 of the present invention differs from Embodiment 1 in that the laser beam emitted by the laser irradiation unit is a line-shaped laser beam. Embodiment 2 will be described with reference to Figures 5 and 6. Figure 5 is a diagram illustrating the retaining layer partial removal apparatus in Embodiment 2 of the present invention. Figure 6 is a diagram illustrating the retaining layer partial removal method in Embodiment 2 of the present invention.

[0043] The retaining layer partial removal apparatus 200 in Example 2 has a laser irradiation unit 212 in the retaining layer removal unit 210. The laser irradiation unit 212 can irradiate the substrate 20 with a line-shaped laser in the Y-axis direction. In other words, the line-shaped laser irradiated onto the substrate 20 can irradiate one line in the Y-axis direction over the entire arrangement range of the retaining layer 10 in the array region of the semiconductor chip 1. Then, the substrate holding unit 214 moves in the X direction, which is perpendicular to the length direction of the line-shaped laser irradiation, thereby irradiating the entire arrangement range of the retaining layer 10 in the array region of the semiconductor chip 1 with the laser.

[0044] As shown in Figure 6(a), the laser beam 211 emits a line of laser light 60 in the Y-axis direction. This laser light 60 can irradiate the semiconductor chips 1a, 2a, 3a, 4a, and 5a and their surroundings in the Y-axis direction. While irradiating with this laser light 60, the substrate holder 214 is moved in the X-axis direction, thereby performing a retaining layer removal process centered on the second row of semiconductor chips 1b to 5b, the third row of semiconductor chips 1c to 5c, the fourth row of semiconductor chips 1d to 5d, the fifth row of semiconductor chips 1e to 5e, the sixth row of semiconductor chips 1f to 5f, and the seventh row of semiconductor chips 1g to 5g. This allows the laser to irradiate the entire area of ​​the retaining layer 10 in the arrangement region of the semiconductor chips 1.

[0045] Furthermore, in all semiconductor chips, the adhesive holding layer 10 is the same size as or smaller than the size of the second main surface of the semiconductor chip (device), and when transferring the semiconductor chip 1 that is adhesively held on the substrate 20, it can be transferred with high precision without tilting.

[0046] In Example 2, the irradiation range was defined as one line in the Y-axis direction, and the substrate holding unit 214 moved in the X-direction. However, this is not necessarily limited to this configuration, and modifications can be made as appropriate. For example, the irradiation range may be defined as one line in the X-axis direction, and the substrate holding unit 214 may move in the Y-direction. Alternatively, the substrate holding unit 214 may remain stationary, while the laser irradiation unit 212 is moved in a direction perpendicular to the length direction of the linear laser irradiation, or the laser spot may be moved relatively in a direction perpendicular to the length direction of the linear laser beam. Furthermore, there may be more than one linear laser spot; two or more linear lasers may be irradiated simultaneously.

[0047] Thus, in Example 2, the method for partially removing the retaining layer is used in which a portion of the retaining layer is removed from a substrate in which the second main surface of an element is adhesively held via a retaining layer. A method for partially removing a retaining layer is characterized by performing a retaining layer removal step, in which a laser is irradiated from the first main surface side of the element so that the entire arrangement range of the retaining layer in the array region of the element becomes the irradiation range, thereby removing a part of the retaining layer. As a result, the retaining layer becomes the same size as or smaller than the size of the second main surface of the element, the retaining layer does not wrap around to the side of the element, and the element does not tilt during laser lift-off, allowing for accurate transfer.

[0048] Furthermore, in a substrate in which the second main surface of an element is adhesively held via a retaining layer, a retaining layer partial removal device for removing a portion of the retaining layer is provided, A laser irradiation unit that emits laser light, A substrate holding portion for holding the substrate, A partial retention layer removal device is characterized by comprising: a control unit that moves relative to the substrate holding unit while irradiating laser light from the laser irradiation unit from the first main surface side of the element, and controls the unit so that the entire arrangement range of the retention layer in the element arrangement region becomes the laser irradiation range. As a result, the retention layer becomes the same size as or smaller than the size of the second main surface of the element, the retention layer does not wrap around the side of the element, and the element does not tilt during laser lift-off, allowing for accurate transfer. [Industrial applicability]

[0049] The method and apparatus for partially removing the retaining layer according to the present invention can be widely used in fields where elements such as semiconductor chips are transferred and mounted. [Explanation of Symbols]

[0050] 1(1a, 1b, 1c, 1d, 1e, 1f, 1g): Semiconductor chip 2(2a, 2b, 2c, 2d, 2e, 2f, 2g): Semiconductor chip 3(3a, 3b, 3c, 3d, 3e, 3f, 3g): Semiconductor chip 4(4a, 4b, 4c, 4d, 4e, 4f, 4g): Semiconductor chip 5(5a, 5b, 5c, 5d, 5e, 5f, 5g): Semiconductor chip 1A: First main surface 1B: Second main surface 10: Retaining layer 19: Wrap-around retaining layer 20: Substrate 21: First main surface 22: Second main surface 30: Substrate to be transferred 100: Retaining layer partial removal device 110: Retaining layer removal unit 111: Laser light 112: Laser irradiation unit 114: Substrate holding unit 115: Galvano mirror 116 fθ lens 200: Partial retention layer removal device 210: Retention layer removal section 211: Laser beam 212: Laser irradiation section 214: Substrate holding section

Claims

1. A method for partially removing a retaining layer in a substrate in which a second main surface of an element is held via a retaining layer, wherein a portion of the retaining layer is removed. A method for partially removing a retaining layer, characterized in that a laser is irradiated from the first main surface side of the element such that the entire arrangement range of the retaining layer, including the entire first main surface of the element in the element arrangement region, becomes the irradiation range, thereby performing a retaining layer removal step to remove a part of the retaining layer.

2. The method for partially removing a retaining layer according to claim 1, characterized in that the laser spot irradiated in the retaining layer removal step is sized to include at least the entire first main surface of at least one element and the retaining layer surrounding the element, and the laser having the laser spot is moved relative to irradiates the entire area of ​​the retaining layer arrangement in the element arrangement region with the laser.

3. The method for partially removing a retaining layer according to claim 1, characterized in that the laser irradiated in the retaining layer removal step is in the shape of a line, and the laser irradiation is moved relatively in a direction perpendicular to the length direction of the line-shaped laser irradiation, thereby irradiating the entire area of ​​the retaining layer arrangement in the element arrangement region with the laser.

4. A retaining layer partial removal apparatus for a substrate in which the second main surface of an element is held via a retaining layer, wherein a portion of the retaining layer is removed. A laser irradiation unit that emits laser light, A substrate holding portion for holding the substrate, A retaining layer partial removal apparatus comprising: a control unit that moves relative to the substrate holding unit while irradiating laser light from the laser irradiation unit from the first main surface side of the element, and controls the entire arrangement range of the retaining layer, including the entire first main surface of the element in the element arrangement region, so that the laser irradiation range becomes the entire arrangement range of the retaining layer.

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