Removal method of carrier plate

Abstract

To provide a removal method of a carrier plate that allows a carrier plate to be easily removed from a plate-like workpiece fixed to a carrier plate via a laminate, and also allows the workpiece to be easily handled even after the carrier plate is removed.SOLUTION: A removal method of a carrier plate includes a fixing step of fixing a reinforcing plate to a workpiece while the workpiece is fixed to a carrier plate via a laminate, a laminate partial removal step of removing at least a portion of the laminate such that a release layer is exposed along the outer peripheral edge of the workpiece, and a separation removal step of separating and removing the carrier plate from the workpiece by separating the laminate into a portion on the carrier plate side and a portion on the workpiece side at the release layer after the laminate partial removal step.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for removing a carrier plate, which is used to separate and remove a carrier plate from a plate-shaped workpiece that is fixed to the carrier plate via an adhesive laminate. [Background technology]

[0002] In the manufacturing process of semiconductor devices, for example, a plate-shaped workpiece including a wiring layer called a redistribution layer (RDL) and a device chip may be temporarily fixed to the surface of a carrier plate, which serves as a temporary support, via an adhesive laminate. After the desired workpiece is obtained or processed to a desired state, the carrier plate is separated from the workpiece at a boundary of some of the layers that make up the laminate.

[0003] As a method for separating and removing a carrier plate from a workpiece, for example, a method has been proposed in which the outer edge of the carrier plate is machined into a stepped shape that protrudes laterally beyond the workpiece, and force is applied to the stepped portion of the carrier plate while the workpiece is held (see, for example, Patent Document 1). With this method, the stepped portion of the carrier plate is properly exposed even when the workpiece is held, so the force required to separate the carrier plate can be easily applied to the carrier plate.

[0004] Another method proposed for separating and removing the carrier plate from the workpiece is, for example, to make a cut through the above-mentioned laminate in the thickness direction and separate the laminate into two parts in the thickness direction from the cut (see, for example, Patent Document 1). According to this method, the cross section of the laminate is appropriately exposed, so that the laminate can be easily separated into two parts in the thickness direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-119952 [Patent Document 2] Japanese Patent Application Publication No. 2023-67941 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if the workpiece fixed to the carrier plate is thin or if the workpiece is made of a material that is prone to warping, it may be difficult to handle the workpiece after the carrier plate is separated.

[0007] Therefore, the object of the present invention is to provide a method for removing a carrier plate that can easily remove a carrier plate from a plate-shaped workpiece fixed to the carrier plate via a laminate, and that makes it easy to handle the workpiece even after the carrier plate is removed. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a method for removing a carrier plate, which includes: a fixing step for fixing a reinforcing plate to a second surface of the workpiece facing opposite to the first surface, with the workpiece fixed to the carrier plate via a laminate having a carrier plate-side adhesive layer adhered to the surface of the carrier plate, a workpiece-side adhesive layer adhered to the first surface of the plate-shaped workpiece, and a release layer sandwiched between the carrier plate-side adhesive layer and the workpiece-side adhesive layer and not exposed to the outside; a laminate partial removal step for removing at least a portion of the laminate so that the release layer is exposed along the outer peripheral edge of the workpiece; and a separation and removal step for separating the laminate into a carrier plate-side portion and a workpiece-side portion at the release layer after the laminate partial removal step, thereby separating and removing the carrier plate from the workpiece.

[0009] In one aspect of the present invention, the method further includes, before the fixing step, a workpiece portion removal step of removing at least a portion of the second surface side of the workpiece along the portion to be removed in the laminate portion removal step, so that all of the release layer remains with the workpiece fixed to the carrier plate via the laminate, and in the laminate portion removal step, the portion remaining in the workpiece portion removal step is removed along the portion removed in the workpiece portion removal step, so that all of the reinforcing plate remains. [Effects of the Invention]

[0010] In a method for removing a carrier plate according to one aspect of the present invention, a portion of the laminate is removed to expose a release layer along the outer periphery of the workpiece, and the laminate is separated at the release layer into a carrier plate portion and a workpiece portion, allowing for easy removal of the carrier plate from the workpiece. Furthermore, because the workpiece is fixed to the reinforcing plate before the carrier plate is removed from the workpiece, handling of the workpiece is easy even after the carrier plate is removed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing a composite substrate. [Figure 2] FIG. 2 is a cross-sectional view showing a portion of the workpiece being removed along its outer periphery. [Figure 3] FIG. 3 is a cross-sectional view of the composite substrate after a portion of the workpiece has been removed along its outer periphery. [Figure 4] FIG. 4 is a cross-sectional view showing the composite substrate after the stiffener plate has been fixed to the workpiece. [Figure 5] FIG. 5 is a cross-sectional view showing a state in which a part of the laminate is removed. [Figure 6] FIG. 6 is a cross-sectional view showing the composite substrate after a portion of the laminate has been removed to expose a portion of the release layer. [Figure 7] FIG. 7 is a cross-sectional view showing the carrier plate being separated and removed from the workpiece. [Figure 8] FIG. 8 is a cross-sectional view showing the composite substrate after a portion of the workpiece has been removed along its outer periphery in the carrier plate removing method according to the first modified example. [Figure 9] FIG. 9 is a cross-sectional view showing the composite substrate after a part of the laminate has been removed and a part of the release layer has been exposed in the method for removing the carrier plate according to the first modified example. [Figure 10] FIG. 10 is a cross-sectional view showing the composite substrate after the reinforcing plate has been fixed to the workpiece in the carrier plate removing method according to the second modified example. [Figure 11] FIG. 11 is a cross-sectional view showing the composite substrate after a part of the laminate has been removed and a part of the release layer has been exposed in the method for removing the carrier plate according to the second modified example. [Figure 12] FIG. 12 is a cross-sectional view showing the composite substrate after a part of the laminate has been removed and a part of the release layer has been exposed in the method for removing the carrier plate according to the third modified example. [Figure 13] FIG. 13 is a cross-sectional view showing the composite substrate after a part of the laminate has been removed and a part of the release layer has been exposed in the method for removing the carrier plate according to the fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a composite substrate 1 used in a carrier plate removal method according to this embodiment. The composite substrate 1 includes a disk-shaped carrier plate 3 made of glass containing silicon dioxide (SiO2) as a main component, such as soda glass, borosilicate glass, or quartz glass. That is, the carrier plate 3 has a circular first surface (surface) 3a and a circular second surface 3b facing the opposite side to the first surface 3a. The thickness of the carrier plate 3 is, for example, 2 mm or less.

[0013] In this embodiment, a disk-shaped carrier plate 3 made of glass containing silicon dioxide as a main component is used, but the material, shape, structure, size, etc. of the carrier plate 3 in the composite substrate 1 are not limited to this. A plate of any shape made of any material such as a semiconductor, ceramic, or metal can be used as the carrier plate 3 of the composite substrate 1. For example, the carrier plate 3 may be configured as a flat plate with a first surface 3a and a second surface 3b each being rectangular.

[0014] A laminate (temporary adhesive sheet) 5 having a thickness of, for example, 20 μm or less is provided over the entire first surface 3 a of the carrier plate 3. That is, the laminate 5 of this embodiment is configured in a thin, disk-like shape. The laminate 5 includes, for example, an adhesive portion (multilayer adhesive layer) 7 having a laminate structure having an adhesive layer (carrier plate-side adhesive layer) 7 a that is adhered to the first surface 3 a of the carrier plate 3 and an adhesive layer (workpiece-side adhesive layer) 7 b that is not adhered to the carrier plate 3, and a release layer 9 that is sandwiched between the adhesive layers 7 a and 7 b and is not exposed to the outside. That is, the release layer 9 is disposed within the area surrounded by the adhesive portion 7 so as to divide the adhesive portion 7 into two in the thickness direction.

[0015] The adhesive layers 7a and 7b are typically layers containing a metal selected from titanium (Ti), chromium (Cr), aluminum (Al), nickel (Ni), copper (Cu), etc., and the adhesive portion 7 containing these has the function of fixing the plate-shaped workpiece 11 to the carrier plate 3. However, the materials of the adhesive layers 7a and 7b that make up the adhesive portion 7 are not limited to these.

[0016] The material of adhesive layer 7a and the material of adhesive layer 7b may be the same or different. When the material of adhesive layer 7a and the material of adhesive layer 7b are the same, adhesive layer 7a and adhesive layer 7b may be substantially integrated to form adhesive portion 7. Furthermore, adhesive portion 7 may include layers other than adhesive layer 7a and adhesive layer 7b.

[0017] The peeling layer 9 is sandwiched between the adhesive layers 7a and 7b, and divides at least a portion of the adhesive portion 7 into two in the thickness direction. Therefore, for example, by applying a physical force or irradiating with a laser beam, it is possible to separate the portion on one side of the adhesive portion 7 in the thickness direction (adhesive layer 7a) from the portion on the other side (adhesive layer 7b) at the peeling layer 9. Hereinafter, separating the portion on one side of the adhesive portion 7 in the thickness direction from the portion on the other side will sometimes be simply referred to as peeling.

[0018] The release layer 9 can be broadly classified into organic release layers, which are primarily composed of organic materials, and inorganic release layers, which are primarily composed of inorganic materials, depending on their primary component. Examples of organic materials used in the organic release layer include nitrogen-containing organic compounds, sulfur-containing organic compounds, and carboxylic acids. Examples of nitrogen-containing organic compounds include triazole compounds and imidazole compounds.

[0019] On the other hand, inorganic substances used in the inorganic release layer include metal oxides or metal oxynitrides containing metals selected from copper (Cu), titanium (Ti), aluminum (Al), niobium (Nb), zirconium (Zr), chromium (Cr), tungsten (W), tantalum (Ta), cobalt (Co), silver (Ag), nickel (Ni), indium (In), tin (Sn), zinc (Zn), gallium (Ga), molybdenum (Mo), etc., or carbon (C).

[0020] Considering the ease of peeling and the ease of forming the release layer 9, the release layer 9 preferably contains carbon as a main component, more preferably consists of carbon or hydrocarbon, and even more preferably consists of amorphous carbon. Furthermore, the carbon content of the release layer 9, as measured using X-ray photoelectron spectroscopy (XPS), is preferably 60 atomic % or more, more preferably 70 atomic % or more, even more preferably 80 atomic % or more, and particularly preferably 85 atomic % or more.

[0021] By using the carbon-containing release layer 9, interdiffusion of metal elements at the interface with the adhesive layer 7a or 7b is prevented, and easy peeling can be maintained, even when subjected to press working at temperatures exceeding 300°C. In this case, the thickness of the release layer 9 is preferably 1 nm or more and 20 nm or less, and more preferably 1 nm or more and 10 nm or less. The thickness of the release layer 9 can be measured, for example, using a TEM-EDX (energy dispersive X-ray spectroscopy) attached to a transmission electron microscope.

[0022] When a method of peeling by irradiating a laser beam (called laser lift-off, etc.) is employed, the peeling layer 9 may be made of a resin or the like whose adhesive strength at the interface is reduced by irradiation with a laser beam. Alternatively, the peeling layer 9 may be made mainly of silicon (Si), silicon carbide (SiC), metal oxide, or the like, which is modified by irradiation with a laser beam.

[0023] However, the material, shape, structure, size, etc. of release layer 9 are not limited to these. For example, release layer 9 may include two or more of a film mainly composed of metal oxide, a film mainly composed of metal oxynitride, and a film mainly composed of carbon. In addition, the surface of release layer 9 (the interface with adhesive layer 7a or adhesive layer 7b) may be subjected to fluorination treatment and / or nitriding treatment.

[0024] A workpiece 11 is fixed to the first surface 3a of the carrier plate 3 via the laminate 5 configured in this manner. The workpiece 11 is typically a package substrate including a wiring layer (not shown) arranged closer to the laminate 5, a plurality of device chips 13 connected to the wiring layer, and a molded resin layer 15 that seals each device chip 13.

[0025] The workpiece 11 has a first surface 11a having approximately the same size and shape as the first surface 3a of the carrier plate 3, and a second surface 11b facing the opposite side to the first surface 11a and having approximately the same size and shape as the first surface 11a. That is, in this embodiment, the workpiece 11 is also configured in a disk shape. Furthermore, the adhesive layer 7b constituting the adhesive portion 7 of the laminate 5 is adhered to the first surface 11a of the workpiece 11. The thickness of the workpiece 11 is, for example, 1.5 mm or less.

[0026] Planned division lines, called streets or the like, are set in areas between adjacent device chips 13 inside the workpiece 11. By cutting the workpiece 11 along any of the planned division lines, the workpiece 11 is divided into a plurality of workpiece pieces, each including one or more device chips 13.

[0027] Then, by cutting the workpiece 11 (or workpiece pieces) along all of the planned division lines, multiple package devices corresponding to each device chip 13 can be obtained. However, the material, shape, structure, size, etc. of the workpiece 11 are not limited to these. For example, the workpiece 11 may be configured in the shape of a flat plate with a first surface 11a and a second surface 11b that are rectangular to match the shape of the carrier plate 3.

[0028] Furthermore, for example, the workpiece 11 may be composed of only a wiring layer and may not include the device chip 13 or the mold resin layer 15. Furthermore, for example, the workpiece 11 may be a wafer or the like on which a device such as an integrated circuit is provided, or may be a wafer or the like on which no device is provided.

[0029] In the carrier plate removal method according to this embodiment, first, at least a portion of the workpiece 11 constituting the composite substrate 1 is removed along its outer periphery (workpiece portion removing step). Fig. 2 is a cross-sectional view showing how a portion of the workpiece 11 is removed along its outer periphery. Note that in Fig. 2, some components are shown as functional blocks.

[0030] The process of removing a portion of the workpiece 11 along its outer periphery is performed using, for example, a cutting device 2 shown in Fig. 2. The cutting device 2 includes a chuck table 4 for holding the composite substrate 1 from below. The chuck table 4 includes a cylindrical frame 6 made of a metal material such as stainless steel, and a porous holding plate 8 disposed on top of the frame 6.

[0031] The composite substrate 1 is placed on the upper surface 8a of the holding plate 8. The space below the holding plate 8 is connected to a suction source 12 constituted by an ejector or the like via a flow path 6a provided inside the frame 6 and a valve 10 or the like arranged outside the frame 6. Therefore, when the valve 10 is opened, the negative pressure generated by the suction source 12 acts on the upper surface 8a of the holding plate 8 through the flow path 6a.

[0032] The chuck table 4 (frame 6) is connected to a rotary drive source (not shown) such as a motor, and the force generated by this rotary drive source causes it to rotate around a rotation axis that is approximately perpendicular to the upper surface 8a of the holding plate 8. The chuck table 4 (frame 6) is also supported by a processing feed mechanism (not shown), and moves in a direction (processing feed direction) that is approximately parallel to the upper surface 8a of the holding plate 8.

[0033] A cutting unit 14 is disposed above the chuck table 4. The cutting unit 14 is equipped with a spindle 16 that forms a rotation axis that is generally parallel to the upper surface 8a of the holding plate 8. Attached to one end of the spindle 16 is an annular cutting blade 18 that has a structure in which abrasive grains made of diamond or the like are dispersed in a binder made of resin, metal, or the like.

[0034] A rotary drive source (not shown) such as a motor is connected to the other end of the spindle 16, and the cutting blade 18 attached to one end of the spindle 16 rotates by the force generated by this rotary drive source. The cutting unit 14 is supported by, for example, an elevation mechanism (not shown) and an indexing feed mechanism (not shown), and moves in a vertical direction that is approximately perpendicular to the upper surface 8a of the holding plate 8, and in an indexing feed direction that is approximately perpendicular to the vertical direction and the processing feed direction.

[0035] When removing a portion of the workpiece 11 along its outer periphery, first, the composite substrate 1 is placed on the upper surface 8a of the holding plate 8 so that the second surface 3b of the carrier plate 3 faces the upper surface 8a of the holding plate 8. Next, with the suction source 12 operating, the valve 10 is opened. As a result, the negative pressure generated by the suction source 12 acts on the upper surface 8a of the holding plate 8 through the flow path 6a, and the composite substrate 1 is sucked and held by the chuck table 4 with the workpiece 11 exposed upward.

[0036] After the composite substrate 1 is held by the chuck table 4, the positional relationship between the chuck table 4 and the cutting unit 14 is adjusted by the processing feed mechanism, the indexing feed mechanism, the lifting mechanism, etc. Specifically, for example, the positional relationship between the chuck table 4 and the cutting unit 14 is adjusted so that the cutting blade 18 is positioned directly above the portion of the workpiece 11 that is to be processed (first processed portion). In this embodiment, the portion including the outer peripheral edge of the workpiece 11 is defined as the first processed portion, and the cutting blade 18 is positioned directly above this first processed portion.

[0037] Thereafter, for example, the chuck table 4 and the cutting blade 18 are rotated by rotary drive sources connected to them, respectively, and in this state, the cutting unit 14 is lowered by an elevator mechanism or the like. Then, as shown in Figure 2, the rotating cutting blade 18 cuts into the first workpiece portion. Because the chuck table 4 is rotating, the workpiece 11 is machined in a ring shape along its outer periphery.

[0038] For example, when the cutting unit 14 descends to a target position (height), processing of the workpiece 11 is completed. In this embodiment, the target position of the cutting unit 14 is set so that the cutting blade 18 cuts into the workpiece 11 but does not cut into the release layer 9 of the laminate 5. As a result, at least a portion of the second surface 11b side of the workpiece 11 is removed along the outer periphery of the workpiece 11. Furthermore, not all of the release layer 9 is removed and remains.

[0039] In this embodiment, the cutting unit 14 is lowered while the chuck table 4 is rotating, but the chuck table 4 may be rotated after the cutting unit 14 has been lowered to a target position. When machining a flat workpiece 11 whose first surface 11a and second surface 11b are rectangular, instead of rotating the chuck table 4, the chuck table 4 and the cutting unit 14 may move relatively along a first workpiece portion corresponding to one side of the rectangle (i.e., the outer periphery).

[0040] Furthermore, in this embodiment, the positional relationship between the chuck table 4 and the cutting unit 14 is adjusted so that the cutting blade 18 is positioned directly above the first workpiece, but the positional relationship between the chuck table 4 and the cutting unit 14 may also be adjusted so that the cutting blade 18 is positioned directly above an extension line extended from the first workpiece (typically, a tangent to the outer peripheral edge which is circular, or a straight line extending one side of a rectangle, etc.).

[0041] In this case, the cutting unit 14 then descends to the target position (height). Then, the chuck table 4 and the cutting unit 14 move relatively along the extension line, and the cutting blade 18 cuts into the first machined portion of the workpiece 11. Thereafter, the chuck table 4 rotates, or the chuck table 4 and the cutting unit 14 move relatively, thereby machining the workpiece 11 along its outer periphery.

[0042] 3 is a cross-sectional view showing the composite substrate 1 after a portion of the workpiece 11 has been removed along its outer periphery. In this embodiment, the portion including the outer periphery of the workpiece 11 is set as the first processed portion, and therefore a staircase-like step 11c as shown in FIG. 3 is formed on the outer periphery of the workpiece 11. At this stage, the peel layer 9 of the laminate 5 is not exposed to the outside, so even if some processing is performed on the workpiece 11, unintentional peeling of the adhesive portion 7 is highly unlikely to occur.

[0043] After at least a portion of the workpiece 11 has been removed along its outer periphery, a reinforcing plate is fixed to the second surface 11b of the workpiece 11 (fixing step). Fig. 4 is a cross-sectional view showing the composite substrate 1 after the reinforcing plate 17 has been fixed to the workpiece 11. The reinforcing plate 17 has a first surface 17a that has approximately the same size and shape as the first surface 11a of the workpiece 11, and a second surface 17b that faces the opposite side to the first surface 17a and has approximately the same size and shape as the first surface 17a. That is, in this embodiment, the reinforcing plate 17 is also configured in a disk shape.

[0044] This reinforcing plate 17 is made of, for example, the same material as the carrier plate 3, and in this embodiment, is thinner than the carrier plate 3. However, the material, shape, structure, size, etc. of the reinforcing plate 17 are not limited to these. For example, the thickness of the reinforcing plate 17 may be equal to or greater than the thickness of the carrier plate 3. Note that the size of the first surface 17a and the second surface 17b of the reinforcing plate 17 is preferably larger than the second surface 11b of the workpiece 11 after the step portion 11c is formed. The reinforcing plate 17 may be configured as a flat plate with the first surface 17a and the second surface 17b being rectangular, similar to the carrier plate 3, the workpiece 11, etc.

[0045] In this embodiment, the first surface 11a of the reinforcing plate 17 is fixed to the second surface 11b of the workpiece 11 via an adhesive (not shown) such as wax. For example, wax is applied to the second surface 11b of the workpiece 11 and / or the first surface 17a of the reinforcing plate 17, and the composite substrate 1 and the reinforcing plate 17 are stacked together so that the second surface 11b faces the first surface 17a, and pressure is applied, thereby fixing the reinforcing plate 17 to the workpiece 11.

[0046] After the reinforcing plate 17 is fixed to the second surface 11b of the workpiece 11, the composite substrate 1 is processed so that part of the release layer 9 is exposed along the outer peripheral edge of the workpiece 11 (laminate portion removal step). In this embodiment, part of the laminate 5 is removed together with part of the carrier plate 3 and part of the workpiece 11 (step portion 11c). Figure 5 is a cross-sectional view showing how part of the laminate 5 is removed. Note that in Figure 5, some components are shown as functional blocks.

[0047] The processing for exposing a portion of the release layer 9 along the outer peripheral edge of the workpiece 11 is performed, for example, using the above-described cutting device 2. Specifically, first, the composite substrate 1 to which the reinforcing plate 17 is fixed is placed on the upper surface 8a of the holding plate 8 so that the second surface 17b of the reinforcing plate 17 faces the upper surface 8a of the holding plate 8. Next, while the suction source 12 is operating, the valve 10 is opened. As a result, the reinforcing plate 17 fixed to the composite substrate 1 is sucked onto the chuck table 4 with the carrier plate 3 side of the composite substrate 1 exposed upward, and is held together with the composite substrate 1.

[0048] After the composite substrate 1 is held by the chuck table 4, the positional relationship between the chuck table 4 and the cutting unit 14 is adjusted by the processing feed mechanism, the indexing feed mechanism, the lifting mechanism, etc. Specifically, for example, the positional relationship between the chuck table 4 and the cutting unit 14 is adjusted so that the cutting blade 18 is positioned directly above the portion of the composite substrate 1 (carrier plate 3, laminate 5, workpiece 11, etc.) that is to be processed (second processed portion).

[0049] In this embodiment, the portion that overlaps with the step portion 11c of the workpiece 11 when viewed from a direction perpendicular to the second surface 3b of the carrier plate 3 is set as the second processed portion, and the cutting blade 18 is placed directly above this second processed portion. In other words, the second processed portion is set along the removed portion (first processed portion) of the workpiece 11. It can also be said that the first processed portion is set along the portion of the composite substrate 1 that is to be removed, i.e., the second processed portion.

[0050] Thereafter, for example, the chuck table 4 and the cutting blade 18 are rotated by rotary drive sources connected to them, respectively, and in this state, the cutting unit 14 is lowered by an elevation mechanism or the like. Then, as shown in Fig. 5, the rotating cutting blade 18 cuts into the second workpiece portion. Because the chuck table 4 is rotating, the composite substrate 1 is machined into a ring shape along its outer periphery.

[0051] For example, when the cutting unit 14 descends to a target position (height), processing of the composite substrate 1 is completed. In this embodiment, the target position of the cutting unit 14 is set so that the cutting blade 18 cuts into the step 11c of the workpiece 11 but does not cut into the reinforcing plate 17. As a result, part of the carrier plate 3, part of the laminate 5, and part of the workpiece 11 (step 11c) are removed along the removed portion (first processed portion) of the workpiece 11, that is, along the outer periphery of the composite substrate 1. Furthermore, all of the reinforcing plate 17 remains unremoved.

[0052] 5, the cutting unit 14 is lowered to a position where it cuts into the entire step portion 11c of the workpiece 11, but it is sufficient that the cutting unit 14 cuts into at least the release layer 9 of the laminate 5 so as to expose a portion of the release layer 9. The above-described procedure for exposing a portion of the release layer 9 can be modified to suit the case where a portion of the workpiece 11 is removed along the outer peripheral edge (workpiece portion removing step).

[0053] 6 is a cross-sectional view showing the composite substrate 1 after a portion of the laminate 5 has been removed to expose a portion of the release layer 9. In this embodiment, a portion of the workpiece 11 is removed along its outer periphery in advance, so that the shape of the outer periphery of the workpiece 11 can be adjusted without cutting the cutting blade 18 into the reinforcing plate 17, as shown in FIG. 6. This makes it possible to adjust the shape of the outer periphery of the workpiece 11 while reusing the reinforcing plate 17 later.

[0054] After part of the laminate 5 has been removed and part of the release layer 9 has been exposed, the carrier plate 3 is separated and removed from the workpiece 11 (separation and removal step). Specifically, the laminate 5 is separated at the release layer 9 into a portion adhered to the carrier plate 3 side and a portion adhered to the workpiece 11 side. Figure 7 is a cross-sectional view showing how the carrier plate 3 is separated and removed from the workpiece 11.

[0055] The separation of the carrier plate 3 from the workpiece 11 is performed, for example, by using a separation device 20 shown in Fig. 7. The separation device 20 includes a disk-shaped holding pad 22 for holding the composite substrate 1 from above. The holding pad 22 is supported, for example, by a lifting mechanism (not shown), and moves in a vertical direction that is approximately perpendicular to the lower surface 22a of the holding pad 22.

[0056] One end of a flow path (not shown) provided inside the holding pad 22 opens as a suction port (not shown) on the lower surface 22a of the holding pad 22. The other end of the flow path inside the holding pad 22 is connected to a suction source (not shown) constituted by an ejector or the like via a valve (not shown) or the like arranged outside the holding pad 22. Therefore, when the valve is opened, negative pressure generated by the suction source acts on the lower surface 22a of the holding pad 22 through the flow path.

[0057] When separating and removing the carrier plate 3 from the workpiece 11, first, the lower surface 22a of the holding pad 22 comes into contact with the second surface 3b of the carrier plate 3 so that the second surface 3b of the carrier plate 3 faces the lower surface 22a of the holding pad 22. Next, with the suction source operating, the valve is opened. As a result, negative pressure generated by the suction source acts on the lower surface 22a of the holding pad 22 through the flow path inside the holding pad 22, and the carrier plate 3 side of the composite substrate 1 is sucked by the holding pad 22 and held thereon.

[0058] After the carrier plate 3 side of the composite substrate 1 is held by the holding pad 22, for example, measures are taken to suppress the vertical movement of the reinforcing plate 17 (workpiece 11), and then the lifting mechanism raises the holding pad 22. As a result, forces are applied to the adhesive layer 7a, which is bonded to the carrier plate 3 at the adhesive portion 7, and the adhesive layer 7b, which is bonded to the workpiece 11 at the adhesive portion 7, in directions that move them apart, and the laminate 5 is separated (peeled) into the carrier plate 3 side and the workpiece 11 side at the peel layer 9.

[0059] That is, the distance between adhesive layer 7a, which is the portion of adhesive portion 7 on the carrier plate 3 side, and adhesive layer 7b, which is the portion on the workpiece 11 side, increases, and carrier plate 3 is separated from workpiece 11. Measures to suppress the vertical movement of reinforcing plate 17 include measures to hold reinforcing plate 17 with a jig such as chuck table 4 described above, and measures to fix laterally protruding portion 17c of reinforcing plate 17 from above or the side with a fixing jig.

[0060] In this embodiment, the carrier plate 3 is separated from the workpiece 11 by fixing the workpiece 11 (reinforcing plate 17) side and moving the carrier plate 3 side, but the carrier plate 3 may also be separated from the workpiece 11 by fixing the carrier plate 3 side and moving the workpiece 11 side.

[0061] That is, it is sufficient if the carrier plate 3 and the workpiece 11 move in directions that separate them from one another. For example, with the carrier plate 3 side of the composite substrate 1 held from above by the holding pad 22, the carrier plate 3 can be separated from the workpiece 11 by pressing the laterally protruding portion 17c of the reinforcing plate 17 downward with a pressing member.

[0062] Furthermore, in this embodiment, the carrier plate 3 is separated from the workpiece 11 in a state where the carrier plate 3 is above the reinforcing plate 17 (workpiece 11), but the positional relationship between the reinforcing plate 17 and the carrier plate 3 is not limited to this. For example, the carrier plate 3 may be separated from the workpiece 11 in a state where the reinforcing plate 17 is above the carrier plate 3 (a state where the reinforcing plate 17 is held from above by the holding pad 22).

[0063] As described above, in the method for removing a carrier plate according to this embodiment, a portion of the laminate 5 is removed so that the release layer 9 is exposed along the outer peripheral edge of the workpiece 11, and therefore the laminate 5 can be separated at the release layer 9 into a portion on the carrier plate 3 side (a portion including the adhesive layer 7a) and a portion on the workpiece 11 side (a portion including the adhesive layer 7b), and the carrier plate 3 can be easily removed from the workpiece 11. Furthermore, because the workpiece 11 is fixed to the reinforcing plate 17 before the carrier plate 3 is removed from the workpiece 11, the workpiece 11 can be easily handled even after the carrier plate 3 is removed.

[0064] The present invention is not limited to the above-described embodiment and can be implemented in various modifications. For example, in the above-described embodiment, a portion of the workpiece 11 is removed along its outer periphery to form a stepped step 11c on the outer periphery of the workpiece 11. However, the outermost portion of the workpiece 11 does not necessarily have to be removed as long as the release layer 9 can be exposed later.

[0065] Fig. 8 is a cross-sectional view showing the composite substrate 1 after a portion of the workpiece 11 has been removed along its outer periphery in the carrier plate removal method according to the first modified example. In the carrier plate removal method according to the first modified example, as shown in Fig. 8, a portion of the workpiece 11 slightly inside the outermost portion is removed as the first processed portion, thereby forming an annular groove 11d along the outer periphery. The specific processing method is the same as in the above-described embodiment, etc., except for the position where the cutting blade 18 cuts into the workpiece 11.

[0066] After at least a portion of workpiece 11 has been removed along its outer periphery to form groove 11d, a reinforcing plate 17 is fixed to second surface 11b of workpiece 11, as in the above-described embodiment. Then, composite substrate 1 is processed so that a portion of release layer 9 is exposed along the outer periphery of workpiece 11. Figure 9 is a cross-sectional view showing composite substrate 1 after a portion of laminate 5 has been removed and a portion of release layer 9 has been exposed in the carrier plate removal method according to the first modified example.

[0067] 9, in the carrier plate removal method according to the first modified example, the portion that overlaps with groove 11d of workpiece 11 when viewed from a direction perpendicular to second surface 3b of carrier plate 3 is removed as the second processed portion, and groove 1a including the portion that was groove 11d is formed. The specific processing method is the same as that of the above-described embodiment, etc., except for the position where cutting blade 18 cuts into composite substrate 1.

[0068] After part of the laminate 5 has been removed and part of the release layer 9 has been exposed, the carrier plate 3 is separated and removed from the workpiece 11. In this first modified example, for example, the part of the carrier plate 3 inside the groove 1a is held by the holding pad 22, and the part of the carrier plate 3 outside the groove 1a is not held by the holding pad 22. Other points are the same as those in the above-mentioned embodiment.

[0069] Furthermore, in the above-described embodiment and first modified example, the reinforcing plate 17 is fixed to the workpiece 11 after a portion of the workpiece 11 is removed along the outer periphery, but the reinforcing plate 17 may be fixed to the workpiece 11 before a portion of the workpiece 11 is removed along the outer periphery. Fig. 10 is a cross-sectional view showing the composite substrate 1 after the reinforcing plate 17 is fixed to the workpiece 11 in the carrier plate removal method according to the second modified example.

[0070] 10, in the carrier plate removal method according to the second modified example, a part of the workpiece 11 is not removed along the outer periphery (the workpiece part removing step is not performed), and the reinforcing plate 17 is fixed to the second surface 11b of the workpiece 11. The specific fixing method is the same as in the above-described embodiment.

[0071] After the reinforcing plate 17 is fixed to the second surface 11b of the workpiece 11, the composite substrate 1 is processed so that part of the release layer 9 is exposed along the outer peripheral edge of the workpiece 11. Fig. 11 is a cross-sectional view showing the composite substrate 1 after part of the laminate 5 has been removed and part of the release layer 9 has been exposed in the carrier plate removal method according to the second modified example.

[0072] 11 , in the carrier plate removal method according to the second modified example, a portion of the laminate 5 is removed along the outer periphery together with a portion of the reinforcing plate 17, a portion of the workpiece 11, and a portion of the carrier plate 3. Specifically, the carrier plate 3 of the composite substrate 1 is held by the chuck table 4 so that the reinforcing plate 17 is exposed upward, and then the cutting blade 18 cuts into the reinforcing plate 17 and the composite substrate 1.

[0073] In this second modified example, the target position (height) of the cutting unit 14 is set so that the cutting blade 18 cuts into the carrier plate 3 but does not reach the second surface 3b of the carrier plate 3. Other points are the same as those of the above-mentioned embodiment.

[0074] As a result, a portion of the laminate 5 is removed together with a portion of the reinforcing plate 17, a portion of the workpiece 11, and a portion of the carrier plate 3, and a staircase-like step 1b is formed on the outer peripheral edge of the composite substrate 1 (carrier plate 3) as shown in Fig. 11. However, instead of the step 1b, a groove as in the first modified example may be formed in the composite substrate 1 (carrier plate 3). After the portion of the laminate 5 is removed and a portion of the release layer 9 is exposed, the carrier plate 3 is separated from the workpiece 11 and removed, as in the above-described embodiment.

[0075] In the second modified example described above, a portion of the laminate 5 is removed together with a portion of the reinforcing plate 17, a portion of the workpiece 11, and a portion of the carrier plate 3, but a portion of the laminate 5 may also be removed together with a portion of the workpiece 11 and a portion of the carrier plate 3. Fig. 12 is a cross-sectional view showing the composite substrate 1 after a portion of the laminate 5 has been removed and a portion of the release layer 9 has been exposed in the method for removing the carrier plate according to the third modified example.

[0076] In the carrier plate removal method according to the third modified example, similarly to the second modified example, a portion of the workpiece 11 is not removed along the outer periphery (a workpiece portion removing step is not performed), and a reinforcing plate 17 is fixed to the second surface 11b of the workpiece 11. Then, as shown in Fig. 12, a portion of the laminate 5 is removed along the outer periphery together with a portion of the workpiece 11 and a portion of the carrier plate 3.

[0077] Specifically, the reinforcing plate 17 fixed to the composite substrate 1 is held by the chuck table 4 so that the carrier plate 3 is exposed upward, and then the cutting blade 18 cuts into the composite substrate 1. In this third modified example, the target position (height) of the cutting unit 14 is set so that the cutting blade 18 cuts into the workpiece 11 but does not cut into the reinforcing plate 17. Other points are the same as those of the above-mentioned embodiment.

[0078] As a result, a portion of the laminate 5 is removed together with a portion of the workpiece 11 and a portion of the carrier plate 3, and a staircase-like step 1c as shown in Fig. 12 is formed on the outer peripheral edge of the composite substrate 1. However, instead of the step 1b, a groove as in the first modified example may be formed in the composite substrate 1. After the portion of the laminate 5 is removed and a portion of the release layer 9 is exposed, the carrier plate 3 is separated from the workpiece 11 and removed, as in the above-described embodiment.

[0079] In the third modified example described above, when removing a portion of the laminate 5, a portion of the reinforcing plate 17 may also be removed. Fig. 13 is a cross-sectional view showing the composite substrate 1 after a portion of the laminate 5 has been removed and a portion of the release layer 9 has been exposed in the method for removing the carrier plate according to the fourth modified example.

[0080] In the carrier plate removal method according to the fourth modified example, similarly to the second and third modified examples, a portion of the workpiece 11 is not removed along the outer periphery (a workpiece portion removing step is not performed), and the reinforcing plate 17 is fixed to the second surface 11b of the workpiece 11. Then, as shown in Fig. 13, a portion of the laminate 5 is removed along the outer periphery together with a portion of the reinforcing plate 17, a portion of the workpiece 11, and a portion of the carrier plate 3.

[0081] Specifically, the reinforcing plate 17 fixed to the composite substrate 1 is held by the chuck table 4 so that the carrier plate 3 is exposed upward, and then the cutting blade 18 cuts into the composite substrate 1 and the reinforcing plate 17. In this fourth modified example, the target position (height) of the cutting unit 14 is set so that the cutting blade 18 cuts into the reinforcing plate 17 but does not reach the second surface 17b of the reinforcing plate 17. Other points are the same as those of the above-mentioned embodiment.

[0082] As a result, a portion of the laminate 5 is removed together with a portion of the reinforcing plate 17, a portion of the workpiece 11, and a portion of the carrier plate 3, and a staircase-like step 17d is formed on the outer periphery of the reinforcing plate 17 (and the composite substrate 1) as shown in FIG. 13. However, a groove as in the first modified example may be formed in the reinforcing plate 17 (and the composite substrate 1) instead of the step 1b. After the portion of the laminate 5 is removed and a portion of the release layer 9 is exposed, the carrier plate 3 is separated from the workpiece 11 and removed, as in the above-described embodiment.

[0083] In the above-described embodiment and each modified example, at least a portion of the workpiece 11 is removed along the outer periphery or a portion of the release layer 9 is exposed along the outer periphery of the workpiece 11 by cutting with the cutting blade 18, but the present invention is not limited to this. At least a portion of the workpiece 11 may be removed along the outer periphery or a portion of the release layer 9 may be exposed along the outer periphery of the workpiece 11 by irradiating a laser beam (laser ablation).

[0084] In the above-described embodiment and each modified example, the laminate 5 is separated at the peeling layer 9 by moving the carrier plate 3 and the workpiece 11 in directions that separate them relatively, i.e., by applying a physical force, but the present invention is not limited to this. For example, the laminate 5 may be separated at the peeling layer 9 by irradiating the peeling layer 9 or its vicinity with a laser beam.

[0085] In addition, the structures, methods, etc. according to the above-described embodiments and modifications may be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0086] 1: Composite board 1a: Groove 1b: Stepped section 1c: Stepped section 3: Carrier plate 3a: 1st side (front) 3b: 2nd side 5: Laminate (temporary adhesive sheet) 7: Adhesive part (multilayer adhesive layer) 7a: Adhesive layer (carrier plate side adhesive layer) 7b: Adhesive layer (workpiece side adhesive layer) 9: Peeling layer 11: Workpiece 11a: 1st page 11b: 2nd side 11c: Stepped section 11d: Groove 13: Device chip 15: Mold resin layer 17: Reinforcement plate 17a: 1st page 17b: 2nd side 17c: part 17d: Stepped section 2:Cutting device 4: Chuck table 6: Frame 6a: Flow path 8: Holding plate 8a:Top surface 10: Valve 12: Suction source 14: Cutting unit 16: Spindle 18: Cutting blade 20: Separation device 22: Holding pad 22a: Bottom surface

Claims

1. a fixing step of fixing a reinforcing plate to a second surface of the workpiece facing the opposite side to the first surface, with the workpiece fixed to the carrier plate via a laminate having a carrier plate-side adhesive layer adhered to the surface of the carrier plate, a workpiece-side adhesive layer adhered to a first surface of the plate-shaped workpiece, and a release layer sandwiched between the carrier plate-side adhesive layer and the workpiece-side adhesive layer and not exposed to the outside; a laminate portion removing step of removing at least a portion of the laminate so as to expose the release layer along the outer periphery of the workpiece; A method for removing a carrier plate, which includes, after the laminate portion removal step, a separation and removal step of separating the laminate into a portion on the carrier plate side and a portion on the workpiece side at the peel layer, thereby separating and removing the carrier plate from the workpiece.

2. and a workpiece portion removing step, prior to the fixing step, of removing at least a part of the second surface side of the workpiece along the portion to be removed in the laminate portion removing step, so that the entire release layer remains in a state in which the workpiece is fixed to the carrier plate via the laminate; 2. The method for removing a carrier plate according to claim 1, wherein the laminate portion removing step removes the portion remaining in the workpiece portion removing step along with the portion removed in the workpiece portion removing step so that the entire stiffener plate remains.

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