Method for preparing workpiece for processing and processing method

Abstract

To provide a method for preparing a workpiece for processing, in which the workpiece is processed while being held on a table via a resin.SOLUTION: A method for preparing a workpiece for processing includes: a first resin supply step of laying a resin on a table 2; a first laminate formation step of pressing a flat member against the resin to form one piece, and solidifying the resin by an external stimulus to form a first laminate; a resin layer formation step of peeling the flat member from the first laminate to form a first resin layer 31; a sheet laying step of laying a sheet S on the top surface of the first resin layer; a second resin supply step of laying a resin 25 on the sheet; a second laminate formation step of facing and pressing a plate-shaped wafer W being the workpiece held by holding means 4 against the resin to form one piece, and solidifying the resin by an external stimulus to form a second laminate 42; and a third laminate formation step of removing the first resin layer from the second laminate to form a third laminate.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for processing a plate-like workpiece, and more particularly to a method for preparing a workpiece by coating one side of a wafer with resin to form a reference surface for grinding the workpiece into a flat surface, and a method for thinning the workpiece to a predetermined thickness by grinding the workpiece, and also to a method for processing the prepared workpiece. [Background technology]

[0002] Conventionally, when a wafer, which is a plate-shaped workpiece, is thinned, the rigidity of the wafer decreases significantly as the wafer is thinned, causing cracks, deflection, etc. during transportation and processing. To prevent this problem, a grinding method is known in which the wafer is bonded to a rigid support substrate and then ground.

[0003] Furthermore, with regard to such a grinding method, for example, as disclosed in Patent Document 2, it is known that the wafer is fixed to the surface of a support member via a liquid resin that serves as a fixing agent, and then ground to a predetermined thickness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-207606 [Patent Document 2] JP 2011-119578 A Summary of the Invention [Problem to be solved by the invention]

[0005] When performing the processing disclosed in Patent Document 2, it is necessary to achieve small variations in thickness after bonding the wafer, fixing agent, and support member, i.e., high flatness. If the flatness is low (thickness variations are large), it may cause cracks or chipping during grinding. Furthermore, the limit of thinning also depends on this flatness, i.e., there are cases where thinning to the desired thickness is not possible due to low flatness.

[0006] In the apparatus configuration disclosed in Patent Document 2, for example, the post-bonding accuracy (resin thickness variation) is heavily dependent on the parallelism caused by the component accuracy and installation error of each component of the apparatus. Specifically, although the parallelism between the stage (upper base, holding means) that holds the workpiece wafer by suction and the stage (surface plate) that applies the support member and liquid resin can be improved by adjustment, component tolerances and installation errors make it impossible to achieve the desired accuracy. The thickness variation of the bonded resin determines the limit of thinning when the composite wafer is ground. This can lead to problems such as the wafer not reaching the desired thickness, or even if it does reach the desired thickness, the wafer's thickness variation is so large that the post-processing quality is poor.

[0007] Furthermore, the above-mentioned parallelism adjustment process is not only necessary for thinning the workpiece, but is also an essential process for coating one side of the wafer with resin to form a reference surface for grinding the workpiece to a flat surface. This adjustment process requires a large number of steps, and improvements were needed.

[0008] In view of the above problems, the present invention proposes a novel technique for processing a workpiece while it is held on a table via resin. [Means for solving the problem]

[0009] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0010] According to one aspect of the present invention, a method for preparing a workpiece for processing includes: a first resin supply step of laying resin on a table; a first laminate formation step of pressing a flat member held by a holding means against the resin laid on the top surface of the table to form one body, and solidifying the resin sandwiched between the flat member and the table by applying an external stimulus to form a first laminate; a resin layer formation step of peeling the flat member from the first laminate to form a first resin layer; a sheet laying step of laying a sheet on the top surface of the first resin layer after the resin layer formation step; a second resin supply step of laying resin on the sheet; a second laminate formation step of pressing a plate-shaped workpiece held by the holding means against the resin laid on the top surface of the sheet to form one body, and solidifying the resin sandwiched between the sheet and the workpiece by applying an external stimulus to form a second laminate; and a third laminate formation step of removing the first resin layer from the second laminate to form a third laminate.

[0011] According to one aspect of the present invention, there are provided a first resin supplying step of laying resin on a table, a first laminate forming step of pressing a flat member held by a holding means against the resin laid on the top surface of the table to form a first laminate, and solidifying the resin sandwiched between the flat member and the table by an external stimulus to form a first laminate, a resin layer forming step of peeling the flat member from the first laminate to form a first resin layer, and a sheet laying step of laying a sheet on the top surface of the first resin layer after the resin layer forming step, and The method for preparing a workpiece for processing includes a plate-like object setting step of setting a plate-like object on the upper surface of the sheet after the step, a second resin supply step of laying resin on the plate-like object, a second laminate formation step of pressing the plate-like workpiece held by the holding means against the resin laid on the upper surface of the plate-like object to form one body, and solidifying the resin sandwiched between the plate-like object and the workpiece by an external stimulus to form a second laminate, and a third laminate formation step of removing the first resin layer and the sheet from the second laminate to form a third laminate.

[0012] According to another aspect of the present invention, the area of ​​the lower surface of the flat member is larger than the area of ​​the lower surface of the workpiece.

[0013] According to one aspect of the present invention, the area of ​​the lower surface of the flat member is larger than the area of ​​the lower surface of the plate-like object and the area of ​​the lower surface of the workpiece, and the area of ​​the upper surface of the plate-like object is larger than the area of ​​the lower surface of the workpiece.

[0014] According to one aspect of the present invention, the resin is a liquid resin that hardens in response to an external stimulus.

[0015] According to one aspect of the present invention, the processing method includes a holding step for holding the sheet of the third laminate prepared by the processing preparation method for the workpiece on the holding surface of a chuck table of a grinding device, and a grinding step for grinding the upper surface of the workpiece using a grinding means of the grinding device to thin it to a desired thickness.

[0016] According to one aspect of the present invention, the processing method includes a holding step for holding the plate-like object of the third laminate prepared by the processing preparation method for the workpiece on a holding surface of a chuck table of a grinding device, and a grinding step for grinding the upper surface of the workpiece using a grinding means of the grinding device to thin it to a desired thickness. [Effects of the Invention]

[0017] The present invention provides the following effects. That is, according to one aspect of the present invention, even if high parallelism cannot be ensured in the components of the device for forming the resin layer due to component tolerances or installation errors, it is possible to prepare a third laminate having high-precision flatness with extremely low thickness variation. In addition, in the third laminate, the workpiece is fixed with resin, making it possible to provide a state suitable for thinning the workpiece exposed on the upper surface.

[0018] Furthermore, according to one aspect of the present invention, the first resin layer can be reused as a "reference surface," and the "reference surface" can be continuously utilized without having to perform a resin layer formation step to form a "reference surface" for each workpiece, thereby improving throughput. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a diagram showing an outline of the configuration of a bonding device. [Figure 2] 1A is a diagram illustrating a first resin supplying step, and FIG. 1B is a diagram illustrating a first laminate forming step. [Figure 3] 1A is a diagram showing a resin layer forming step, and FIG. 1B is a diagram showing a state in which a first resin layer has been formed on a sheet. [Figure 4] 1A is a diagram showing a sheet laying step, and FIG. 1B is a diagram showing a state in which the sheet is laid on the first resin layer 31. [Figure 5] 1A is a diagram illustrating a second resin supplying step, and FIG. 1B is a diagram illustrating a second laminate forming step. [Figure 6] 1A is a diagram illustrating a third laminate formation step, and FIG. 1B is a diagram illustrating the third laminate. [Figure 7] (A) is a diagram showing the holding step, and (B) is a diagram showing the grinding step. [Figure 8] 1A is a diagram illustrating how thickness variations do not occur in Example 1 of the present invention, and FIG. 1B is a diagram illustrating how thickness variations occur in a comparative example not according to the present invention. [Figure 9] FIG. 10 is a diagram illustrating a plate-like object installation step according to a second embodiment of the present invention. [Figure 10] 10A is a diagram illustrating a second resin supplying step in Example 2. FIG. 10B is a diagram illustrating a second laminate forming step in Example 2. FIG. [Figure 11] 10A is a diagram illustrating a third laminate formation step in Example 2. FIG. 10B is a diagram illustrating a third laminate formation step in Example 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing an outline of the configuration of a bonding device used to prepare a workpiece for processing. Fig. 1 shows how a wafer W, which is a workpiece, is placed face-to-face with resin 25 laid on the upper surface of a sheet S in the bonding device 1.

[0021] The bonding device 1 is configured to include a table 2, a holding means 4 (holding pad), a lifting means 6, an ultraviolet light irradiation means 5, a resin supplying means 3, and a control device 7 for controlling various operating parts.

[0022] The table 2 has a horizontal upper surface 2a and is configured to transmit ultraviolet light, and is made of a transparent material such as glass. A suction groove that leads to a suction source (not shown) is formed on the horizontal upper surface 2a, and by generating negative pressure on the upper surface 2a, the upper surface 2a is configured to function as a suction holding surface.

[0023] The holding means 4 is disposed above the horizontal upper surface 2a of the table 2, and its horizontal lower surface 4a has suction grooves formed therein that communicate with a suction source (not shown), and by generating negative pressure on the lower surface 4a, the lower surface 4a is configured as a suction holding surface. One side (upper surface) of the wafer W, which is the workpiece, is suction-held by the lower surface 4a, and the other side (lower surface) is exposed.

[0024] The holding means 4 is fixed to the underside of the lifting base 61 of the lifting means 6, and moves up and down together with the lifting base 61. The lifting means 6 has an actuator (not shown), and the lifting base 61 moves up and down by operating the actuator.

[0025] The ultraviolet light irradiation means 5 is disposed below the table 2 and has a light source 5a for emitting ultraviolet light. As will be described in detail later, the ultraviolet light passes through the table 2 and the sheet S and solidifies the resin 25.

[0026] The resin supply means 3 has a supply nozzle 3a for supplying liquid resin 25 onto the upper surface of a sheet S or the like laid on the table 2. The supply nozzle 3a is configured to be movable by an actuator (not shown), and can be positioned at a supply position where the supply nozzle 3a is positioned at the center of the table 2, and at a retracted position where the supply nozzle 3a is away from the table 2. The supply nozzle 3a is connected to a resin supply source (not shown), and can supply a predetermined amount of resin 25 onto the upper surface of the sheet S or the like.

[0027] Next, a processing preparation method using the bonding device configured as above will be described. [Example]

[0028] <First resin supply step> As shown in FIG. 2(A), this is a step in which a resin 25 is laid on a table 2.

[0029] Specifically, a supply nozzle 3a is positioned above the approximate center of the horizontal upper surface 2a of the table 2, and a predetermined amount of resin 25 is supplied to the upper surface 2a by dripping resin 25 from the supply nozzle 3a. The resin 25 is, for example, an ultraviolet-curable resin, such as "Regilock" (registered trademark) manufactured by Disco Corporation. After solidifying, the resin 25 transmits ultraviolet light.

[0030] <First Laminate Forming Step> As shown in Figures 2(A) and (B), this is a step in which the flat member 8 held by the holding means 4 is pressed against the resin 25 laid on the upper surface 2a of the table 2 to form one piece, and the resin 25 sandwiched between the flat member 8 and the table 2 is solidified by an external stimulus to form a first laminate 41.

[0031] Specifically, first, supply nozzle 3a is retracted away from a position below holding means 4. Then, upper surface 8a of flat member 8 is held by suction on lower surface 4a of holding means 4, and flat member 8 is lowered by elevating means 6 (FIG. 1). When lower surface 8b of flat member 8 reaches resin 25, resin 25 is spread between flat member 8 and table 2 without any gaps.

[0032] The area of ​​the lower surface 8b of the flat member 8 is larger than the area of ​​the lower surface Wb of the workpiece (wafer) described later. For example, in the case where the wafer described later is 12 inches, a silicon wafer having a diameter of 306 mm is used, which is larger than the wafer. As a result, as shown in FIG. 6(A), the area of ​​the first resin layer 31 described later can be larger than the area of ​​the wafer W, and the first resin layer 31 can support the wafer W. The total thickness variation (TTV) of the flat member 8 is preferably 3 μm or less, and more preferably 1 μm or less. The flat member 8 may be a silicon wafer or, for example, a plate made of a glass material. The shape of the flat member 8 may be a circular plate or a rectangular shape.

[0033] 2(B), the flat member 8 is lowered to a predetermined height relative to the table 2 to press the resin 25, and ultraviolet light UV is irradiated from below by the ultraviolet light irradiation means 5 (FIG. 1), and the resin 25 is irradiated with ultraviolet light UV through the table 2 to harden the resin 25. As a result, the resin 25 having a predetermined thickness is hardened.

[0034] In this way, in this embodiment, ultraviolet light is used as the means of external stimulus for solidifying the resin 25. Other external stimuli include, for example, heat, and in this case, it is possible to use a thermosetting resin as the resin.

[0035] <Resin layer formation step> This is a step in which the flat member 8 is peeled off from the first laminate 41 shown in FIG. 2(B) to form the first resin layer 31 as shown in FIG. 3(A).

[0036] As shown in FIG. 3(A), the first resin layer 31 remains on the upper surface 2a of the table 2, and the inclination of the flat member 8 (FIG. 2(A)) is transferred to the upper surface 31a of the first resin layer 31. In the example of FIG. 3(A), the upper surface 31a of the first resin layer 31 is inclined at an angle θ so that the right side is lower, and this angle θ is the same as the angle of inclination of the flat member 8 (holding means 4) as shown in FIG. 2(A). Note that in FIG. 2(A), the inclination of the flat member 8 is also the inclination of the holding means 4, and the flat member 8 held by the holding means 4 is held at an inclination of angle θ.

[0037] Fig. 3(B) is a plan view of Fig. 3(A), showing a state in which the flat member 8 (Fig. 2(A)) is peeled off, thereby forming a first resin layer 31 on the table 2. The first resin layer 31 transmits ultraviolet light.

[0038] Peeling between the first resin layer 31 and the flat member 8 (Figure 2(A)) can be easily performed because the resin 25 is solidified by ultraviolet light to become the first resin layer 31, and the adhesive force in the peeling direction is weak.

[0039] <Sheet laying steps> As shown in FIG. 4(A), this is a step of placing a sheet S on the upper surface of the first resin layer 31 after the resin layer forming step. The sheet S is made of, for example, a film made of a transparent PET (polyethylene terephthalate) material that transmits ultraviolet light.

[0040] Fig. 4(B) is a plan view of Fig. 4(A) and shows the state in which the sheet S is placed on the first resin layer 31. The diameter of the sheet S is larger than the diameter of the first resin layer 31, but is not particularly limited thereto. The shape of the sheet may be circular or rectangular.

[0041] As shown in FIG. 4(A), the sheet S is placed on the upper surface 31a of the first resin layer 31 inclined at an angle θ, and the upper surface Sa of the sheet S is also inclined at the angle θ.

[0042] <Second resin supply step> As shown in FIG. 5(A), this is a step of laying a resin 25 on a sheet S. Specifically, a supply nozzle 3a is positioned above the sheet S, and a predetermined amount of resin 25 is supplied to the upper surface Sa of the sheet S by dripping the resin 25 from the supply nozzle 3a onto the upper surface Sa of the sheet S. This resin 25 may be the same as or different from the resin used in the first laminate formation step described above.

[0043] <Second Laminate Forming Step> As shown in Figures 5(A) and (B), this is a step in which the workpiece, a plate-shaped wafer W held by holding means 4, is pressed against resin 25 laid on the upper surface of sheet S to form one piece, and the resin 25 sandwiched between sheet S and wafer W is solidified by an external stimulus to form a second laminate 42.

[0044] Specifically, first, the supply nozzle 3a is retracted away from a position below the holding means 4. Then, the back surface Wb of the wafer W is held by suction on the lower surface 4a of the holding means 4, and the wafer W is lowered by the elevating means 6 (FIG. 1). When the wafer W reaches the resin 25, the resin 25 is spread without leaving any gaps between the wafer W and the sheet S.

[0045] The wafer W is, for example, a silicon wafer, which is to be thinned later by grinding the back surface Wb. The workpiece may be an oxide wafer, a compound wafer, a device wafer, a mold wafer, or the like, in addition to a silicon wafer. The upper surface of the wafer W, i.e., the surface held by the holding means 4, is supported by the holding means 4, so that the wafer W does not bend when the resin 25 is pressed against it.

[0046] Then, as shown in Figure 5(B), while the resin 25 is pressed by the wafer W, ultraviolet light UV is irradiated from below by the ultraviolet light irradiation means 5 (Figure 1), and the ultraviolet light UV is irradiated onto the resin 25 through the table 2, the first resin layer 31, and the sheet S, thereby solidifying the resin 25.

[0047] In this way, in this embodiment, ultraviolet light is used as the means of external stimulus for solidifying the resin 25. Other external stimuli include, for example, heat, and in this case, it is possible to use a thermosetting resin as the resin.

[0048] In this manner, the second resin layer 32 is formed between the wafer W and the sheet S. The second resin layer 32 transmits ultraviolet light.

[0049] <Third Laminate Forming Step> 6(A) and 6(B), this is a step in which the wafer W is released from the holding means 4 and the first resin layer 31 is removed from the second laminate 42 to form a third laminate 43. In other words, this is a step in which the sheet S is peeled off from the first resin layer 31 to form the third laminate 43. The third laminate 43 is configured to include the sheet S, the second resin layer 32, and the wafer W.

[0050] Peeling between the first resin layer 31 and the sheet S can be easily performed because the resin 25 has been solidified by ultraviolet light to become the first resin layer 31 and the adhesive strength in the direction of peeling them off is weak.

[0051] As described above, the upper surfaces of the sheet S and the second resin layer 32 were inclined at the angle θ, and the wafer W was also held by the holding means 4 at an angle θ, so the lower surface Sb of the sheet S and the exposed surface of the wafer W, that is, the back surface Wb of the wafer W, are parallel to each other. Therefore, as shown in FIG. 6(B), if the lower surface Sb of the sheet S is made parallel to the horizontal plane H, the back surface Wb of the wafer W also becomes horizontal, and it becomes possible to thin the wafer W to a uniform thickness in the subsequent thinning process.

[0052] The method for forming the third stack 43 as described above is a preparation method for processing the workpiece, that is, the wafer W. Then, the third stack 43 prepared in this manner is processed as follows.

[0053] As shown in FIG. 6(B), after the third laminate formation step, the first resin layer 31 can remain on the upper surface 2a of the table 2, resulting in the same state as after the resin layer formation step shown in FIG. 3(A). Therefore, when creating a third laminate 43 equivalent to another wafer W or other workpiece, the resin layer formation step can be omitted. In other words, the first resin layer 31 can be reused as a "reference surface," and the "reference surface" can be used continuously without performing a resin layer formation step to form a "reference surface" for each workpiece, thereby improving throughput.

[0054] <Holding step> 7(A), this is a step of holding the lower surface Sb of the sheet S of the third stack 43 on a holding surface 71a of a chuck table 71 of a grinding device 70. By holding the lower surface Sb of the sheet S on the chuck table 71, the back surface Wb of the wafer W, which is the workpiece, is exposed.

[0055] The grinding device 70 is mainly composed of a chuck table 71 and a grinding unit 72, and grinds the back surface Wb of the wafer W, which is the workpiece, to thin the wafer W. A suction groove (not shown) is formed in the holding surface 71a of the chuck table 71, and the third stack 43 is sucked and held on the holding surface 71a by generating negative pressure in the suction groove. The chuck table 71 is configured to rotate by a rotation mechanism (not shown).

[0056] The grinding unit 72 has a grinding wheel 74 in which a plurality of grinding stones 74a are arranged at intervals in an annular shape. The grinding wheel 74 is rotated at a predetermined speed by a rotation mechanism (not shown) and is fed for grinding at a predetermined speed by a grinding feed mechanism (not shown).

[0057] <Grinding step> As shown in FIG. 7(B), this is a step in which the back surface Wb, which is the upper surface of the wafer W, is ground by a grinding unit 72, which is a grinding means of a grinding device, to thin the wafer W to a desired thickness.

[0058] Specifically, the chuck table 71 is rotated to rotate the third stack 43, and the grinding wheel 74 is rotated and fed downward for grinding, thereby grinding the back surface Wb of the wafer W and thinning the wafer W to a predetermined thickness. Because the wafer W is fixed to the rigid second resin layer 32, grinding can be performed while suppressing the occurrence of cracks, warping, and the like.

[0059] Note that mechanical adhesion (anchor effect) is achieved between the second resin layer 32 and the sheet S, and between the second resin layer 32 and the wafer W, by the liquid resin filling the gaps and solidifying. Therefore, no misalignment occurs between the layers constituting the third laminate 43 during grinding, and processing can be carried out stably.

[0060] According to the above-described embodiments, even if, for example, as shown in FIG. 2(A), the lower surface 4a of the holding means 4, which is a component of the bonding device 1, is inclined and not parallel to the horizontal upper surface 2a of the table 2, in other words, high parallelism cannot be ensured due to component tolerances or installation errors, in the third laminate 43 shown in FIG. 6(B), the lower surface Sb of the sheet S and the lower surface 32b of the second resin layer 32 can be made parallel to the processing surface (back surface Wb) of the wafer W, which is the workpiece.

[0061] As a result, as shown in Fig. 8(A), the wafer W is uniformly thinned during grinding, and a thinned wafer W without thickness variations can be obtained. Eliminating thickness variations can improve the quality of the chips that are finally manufactured.

[0062] 8(B) shows a comparative example that does not conform to this embodiment, in which a wafer W, which is a workpiece, is integrated with a second plate-like object 120 via a resin layer 132. Because the back surface Wb of the wafer W is tilted, the wafer W is not uniformly thinned during grinding, resulting in thickness variations. Such thickness variations may result in poor quality of the chips that are ultimately manufactured. [Example]

[0063] 2 to 4 are the same as those in Example 1, so the explanation of Example 2 will be omitted. After that, the "plate-like object installation step," "second resin supply step," "second laminate formation step," and "third laminate formation step" are performed.

[0064] In Example 2, the area of ​​the lower surface 8b (FIG. 2(A)) of the flat member 8 is larger than the area of ​​the lower surface 20b of the plate-like object 20 and the area of ​​the lower surface Wb of the workpiece (wafer). For example, in the case where the wafer described below is 12 inches, a silicon wafer having a diameter of 306 mm, which is larger than the diameter of the wafer, is used. As a result, as shown in FIG. 11(A), the area of ​​the upper surface of the first resin layer 31 can be made larger than the area of ​​the lower surfaces of the plate-like object 20 and the wafer W, and the plate-like object 20 and the wafer W can be supported by the first resin layer 31. Furthermore, by making the area of ​​the upper surface 20a of the plate-like object 20 larger than the area of ​​the lower surface of the wafer W, the wafer W can be supported by the plate-like object 20.

[0065] <Plate installation step> As shown in FIG. 9, this is a step of placing a plate-like object 20 on the upper surface Sa of the sheet S after the sheet laying step.

[0066] Here, the plate-like object 20 is made of, for example, a plate material made of a transparent glass material that transmits ultraviolet light and has high rigidity. The purpose of using the plate-like object 20 is to bond and integrate it with the wafer to be thinned later, so that it functions as a support member for the wafer and suppresses cracking and warping of the wafer. In addition, it is preferable that the plate-like object 20 has a good TTV (Total Thickness Variation).

[0067] Since the plate-like object 20 is placed on the upper surface Sa of the sheet S which is inclined at the angle θ, the upper surface 20a of the plate-like object 20 is also inclined at the angle θ.

[0068] <Second resin supply step> As shown in FIG. 10(A), this is a step of laying a resin 25 on a plate-like object 20.

[0069] Specifically, a supply nozzle 3a is positioned above the plate-like object 20, and a predetermined amount of resin 25 is supplied to the upper surface 20a of the plate-like object 20 by dripping the resin 25 from the supply nozzle 3a onto the upper surface 20a of the plate-like object 20. This resin 25 may be the same as or different from the resin used in the first laminate formation step described above.

[0070] <Second Laminate Forming Step> As shown in Figures 10(A) and (B), this is a step in which the workpiece, a plate-shaped wafer W held by holding means 4, is pressed against resin 25 laid on the upper surface 20a of the plate-shaped object 20 to form one piece, and the resin 25 sandwiched between the plate-shaped object 20 and the wafer W is solidified by an external stimulus to form a second laminate 142.

[0071] Specifically, first, the supply nozzle 3a is retracted away from a position below the holding means 4. Then, the back surface Wb of the wafer W is held by suction on the lower surface 4a of the holding means 4, and the wafer W is lowered by the elevating means 6 (FIG. 1). When the wafer W reaches the resin 25, the resin 25 is spread without leaving any gaps between the wafer W and the plate-like object 20.

[0072] Then, as shown in Figure 10(B), while the resin 25 is pressed by the wafer W, ultraviolet light UV is irradiated from below by the ultraviolet light irradiation means 5 (Figure 1), and the ultraviolet light UV is irradiated onto the resin 25 through the table 2, the first resin layer 31, the sheet S, and the plate-like object 20, thereby solidifying the resin 25.

[0073] In this way, in this embodiment, ultraviolet light is used as the means of external stimulus for solidifying the resin 25. Other external stimuli include, for example, heat, and in this case, it is possible to use a thermosetting resin as the resin.

[0074] In this manner, the second resin layer 32 is formed between the wafer W and the plate-like object 20. The second resin layer 32 is transparent to ultraviolet light.

[0075] <Third Laminate Forming Step> 11(A) and 11(B), this is a step in which the wafer W is released from the holding means 4 and the first resin layer 31 and the sheet S are removed from the second stack 142 to form a third stack 143. In other words, this is a step in which the plate-like object 20 is peeled off from the sheet S to form the third stack 143. The third stack 143 is configured to include the plate-like object 20, the second resin layer 32, and the wafer W.

[0076] Since there is nothing between the plate-like object 20 and the sheet S that contributes to adhesion, the plate-like object 20 can be easily peeled off from the sheet S.

[0077] As described above, the upper surface 20a of the plate-like object 20 is inclined at the angle θ, and the wafer W is also held by the holding means 4 at an angle θ, so the lower surface 20b of the plate-like object 20 and the exposed surface of the wafer W, that is, the back surface Wb of the wafer W, are parallel to each other. Therefore, as shown in Fig. 11(B), if the lower surface 20b of the plate-like object 20 is made parallel to the horizontal plane H, the back surface Wb of the wafer W also becomes horizontal, and it becomes possible to thin the wafer W to a uniform thickness in the subsequent thinning process.

[0078] The third stack 143 is subjected to the holding step and grinding step in the same manner as in the embodiment, thereby thinning the wafers W.

[0079] As described in the above examples, according to the present invention, even if high parallelism cannot be ensured in the components of the device for forming the resin layer due to component tolerances or installation errors, it is possible to prepare a third laminate having high-precision flatness with extremely low thickness variation. Furthermore, in the third laminate, the workpiece is fixed with resin, making it possible to provide a state suitable for thinning the workpiece exposed on the upper surface.

[0080] Furthermore, according to the present invention, the first resin layer can be reused as a "reference surface," and the "reference surface" can be continuously utilized without having to perform a resin layer formation step to form a "reference surface" for each workpiece, thereby improving throughput. [Explanation of symbols]

[0081] 1 Pasting device 2 tables 2a Top surface 2a 3. Resin supply means 3a Supply nozzle 4 Holding means 5 Ultraviolet light irradiation means 6 Lifting means 7 Control Device 8 Flat members 25 Resin 31 First resin layer 32 Second resin layer 41 First laminate 42 Second laminate 43 Third Stack 61 Lifting Platform 70 Grinding equipment 120 Plate-shaped objects 132 Second resin layer 142 Second laminate 143 Third Stack H horizontal plane S seat W wafer

Claims

1. a first resin supply step of laying resin on a table; a first laminate formation step in which the flat member held by the holding means is pressed against the resin laid on the top surface of the table to form a single unit, and the resin sandwiched between the flat member and the table is solidified by an external stimulus to form a first laminate; a resin layer forming step of peeling the flat member from the first laminate to form a first resin layer; a sheet laying step of laying a sheet on an upper surface of the first resin layer after the resin layer forming step; a second resin supply step of laying resin on the sheet; a second laminate formation step in which the plate-shaped workpiece held by the holding means is pressed against the resin laid on the upper surface of the sheet to form a single piece, and the resin sandwiched between the sheet and the workpiece is solidified by an external stimulus to form a second laminate; and a third laminate formation step of removing the first resin layer from the second laminate to form a third laminate.

2. a first resin supply step of laying resin on a table; a first laminate formation step in which the flat member held by the holding means is pressed against the resin laid on the top surface of the table to form a single unit, and the resin sandwiched between the flat member and the table is solidified by an external stimulus to form a first laminate; a resin layer forming step of peeling the flat member from the first laminate to form a first resin layer; a sheet laying step of laying a sheet on an upper surface of the first resin layer after the resin layer forming step; a plate-like object installation step of installing a plate-like object on the upper surface of the sheet after the sheet laying step; a second resin supply step of laying resin on the plate-like object; a second laminate formation step in which the plate-shaped workpiece held by the holding means is pressed against resin laid on the upper surface of the plate-shaped workpiece to form a single piece, and the resin sandwiched between the plate-shaped workpiece and the workpiece is solidified by an external stimulus to form a second laminate; a third laminate formation step of removing the first resin layer and the sheet from the second laminate to form a third laminate.

3. The area of ​​the lower surface of the flat member is larger than the area of ​​the lower surface of the workpiece.

2. The method for preparing a workpiece for processing according to claim 1.

4. the area of ​​the lower surface of the flat member is larger than the area of ​​the lower surface of the plate-like object and the area of ​​the lower surface of the workpiece; The area of ​​the upper surface of the plate-like object is larger than the area of ​​the lower surface of the workpiece.

3. The method for preparing a workpiece for processing according to claim 2.

5. The resin is a liquid resin that hardens when exposed to an external stimulus.

5. The method for preparing a workpiece for processing according to claim 1.

6. The third laminate prepared by the workpiece processing preparation method according to claim 1, a holding step of holding the sheet of the third stack on a holding surface of a chuck table of a grinding device; a grinding step of grinding the upper surface of the workpiece by a grinding means of the grinding device to thin it to a desired thickness; A processing method that performs the above.

7. The third laminate prepared by the workpiece processing preparation method according to claim 2, a holding step of holding the plate-like object of the third stack on a holding surface of a chuck table of a grinding device; a grinding step of grinding the upper surface of the workpiece by a grinding means of the grinding device to thin it to a desired thickness; A processing method that performs the above.

8. The resin is a liquid resin that hardens when exposed to an external stimulus.

8. The processing method according to claim 6 or 7.

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