Sheet, handling sheet, handling method, method for handling thin device, method for removing thinned wafer, method for removing mold-sealed relocation element, method for manufacturing thinned wafer, mold-sealed relocation element, and method for manufacturing package

Abstract

The present invention relates to a sheet characterized by having on a surface thereof a plurality of structural bodies that each have a cylindrical or semicylindrical shape with a height of 50-500 μm and a diameter of 10 μm to 1 mm, or have a prismatic shape with a length of 100 μm to 1 mm and a thickness of 10 μm to 1 mm. The sheet is also characterized by: having on the surface thereof a structure in which the plurality of structural bodies are arranged at an equal interval, or a structure in which the plurality of structural bodies are arranged such that the maximum value of intervals therebetween is less than three-fold of the minimum value of the intervals; and being formed from a thermosetting resin. Accordingly, it is possible to provide: a sheet that enables easy handling of a thinned wafer or a mold-sealed relocated element and that has excellent chemical resistant properties; a thinned wafer handling sheet including the sheet; and a thin wafer handling method and a thin device handling method which use the thinned wafer handling sheet.

Description

[Technical field]

[0001] The present invention relates to a sheet, a sheet for handling thinned wafers, a method for handling thin wafers, and a method for handling thin devices. In particular, the present invention relates to an adhesive sheet for handling thin silicon wafers thinned to 300 microns or less, compound semiconductor wafers, or rectangular glass panels or glass wafers of 1 millimeter or less without damaging them. [Background technology]

[0002] In recent years, in order to increase the density of semiconductor elements, semiconductor element manufacturing is actively carried out using wafers having thicknesses of 300 microns or less, particularly 100 microns or less, rather than the conventional thicknesses of over 500 microns.

[0003] Furthermore, in order to make semiconductor devices three-dimensional, many manufacturing methods have been developed in which semiconductor elements using a wafer thickness of 300 microns or less, particularly 100 microns or less, are rearranged in a functionally required configuration and packaged on a glass panel that has been thinned to 1 millimeter or less, particularly 500 microns or less.

[0004] Regarding the manufacture of such thin wafers and packages using thin panels, for example, the TSV (Through Silicon Via) process, which is an important process for mounting three-dimensional semiconductor elements, involves forming circuits on both the front and back sides of a silicon wafer and forming TSVs (Through Silicon Vias), or so-called through electrodes, to connect them. To form these electrodes, the silicon wafer that will become the semiconductor element is bonded to a supporting glass wafer called a carrier using a temporary adhesive, and then the silicon wafer is thinned and further the circuits are formed.

[0005] In addition, regarding the manufacturing of packages using thin panels, for example, FPGA elements for AI or HBM elements, which are multi-layered DRAM, are rearranged on a thin glass panel to form one function. After the elements are rearranged on the glass panel, the panel is sealed with molding resin, and then thinned and flattened to expose the electrodes and perform circuit formation, etc.

[0006] In the two methods for handling thin substrates described above, a carrier such as a silicon wafer or a glass wafer serves as a supporting base material during circuit formation while the process is being carried out. After the process is completed, it is necessary to remove the silicon wafer with the circuit formed thereon, thinned to 300 microns, or in some cases to 100 microns or less, or the rearrangement elements sealed in a mold.

[0007] Conventionally, when removing the thinned silicon wafer or the mold-sealed repositionable element, a dicing tape using a UV peeling method is generally used, and the dicing tape is attached to the silicon wafer to be removed with the glass carrier connected, and then the carrier is generally removed in this state using a laser peeling method or the like.

[0008] However, the temporary adhesive resin used during the thinning process usually remains on the surface of the thinned silicon wafer having the circuits formed thereon and attached to the dicing tape, which is removed in this manner. This remaining resin must be dissolved and removed by a solvent cleaning method or the like.

[0009] Meanwhile, the adhesive used for dicing tape often uses uncured acrylic resin or the like, and it is known that during the solvent cleaning process of the residual resin of this temporary adhesive, it dissolves in the solvent used, causing problems such as peeling and swelling, and there is a problem that the cleaning solvents that can be used are very limited.

[0010] Patent Document 1 discloses an invention relating to a dry adhesive fiber structure including microfibers with mushroom-shaped ends. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] US Patent Application Publication No. 2015 / 0368519 Summary of the Invention [Problem to be solved by the invention]

[0012] In light of the above-described situation, there has been a need for the development of a tool that can easily handle already thinned wafers and rearrangement elements sealed in a mold for the thinning process of silicon wafers and compound semiconductors that are often used for purposes such as the above-mentioned three-dimensional mounting, and that has excellent chemical resistance.

[0013] The present invention has been made to solve the above problems, and aims to provide a sheet with excellent chemical resistance that can easily handle already thinned wafers and rearrangement elements sealed in a mold, a thinned wafer handling sheet including said sheet, and a thin wafer handling method and thin device handling method using said thinned wafer handling sheet. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention provides a sheet characterized in that it has on its surface a plurality of cylindrical or semi-cylindrical structures having a height of 50 microns to 500 microns and a diameter of 10 microns to 1 mm, or a prismatic structure having a length of 100 microns to 1 mm and a thickness of 10 microns to 1 mm, and the plurality of structures are arranged at equal intervals, or the plurality of structures are arranged such that the maximum spacing is less than three times the minimum spacing, and is molded from a thermosetting resin.

[0015] Such a sheet can easily and sufficiently adhere the wafer to the substrate while requiring almost no force to peel it off, allowing the wafer to be easily handled without damage to the already thinned wafer or the repositionable elements sealed in the mold.

[0016] Furthermore, since the sheet of the present invention is formed from a thermosetting resin and has excellent chemical resistance, it becomes possible to use various resins for cleaning temporary adhesives.

[0017] The thermosetting resin is, for example, at least one selected from the group consisting of an acrylic thermosetting elastomer, a silicone thermosetting elastomer, a urethane thermosetting elastomer, and a fluorine-based thermosetting elastomer.

[0018] By using such a thermosetting elastomer as the thermosetting resin, a sheet having superior chemical resistance can be obtained.

[0019] In the present invention, a substrate and The sheet of the present invention laminated on the substrate; The present invention provides a sheet for handling thinned wafers, comprising:

[0020] Such a thinned wafer handling sheet includes the sheet of the present invention, and therefore wafers that have already been thinned and repositionable elements sealed in a mold can be easily handled without being damaged.

[0021] Furthermore, by using the thinned wafer handling sheet of the present invention, the adhesive part has excellent chemical resistance due to the use of a thermosetting elastomer, making it possible to use various resins for cleaning temporary adhesives.

[0022] The present invention also provides a method for handling thin wafers, which comprises adhering a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less to the thinned wafer handling sheet of the present invention and then handling the wafer.

[0023] In the thin wafer handling method of the present invention, almost no force is required for peeling, so even silicon wafers with a thickness of 300 microns or less can be easily removed without damage.

[0024] The present invention also provides a method for handling thin devices, characterized in that a rectangular glass panel or metal panel having a thickness of 1.5 mm or less and carrying a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less is attached to the thinned wafer handling sheet of the present invention and then handled.

[0025] The method for handling thin devices of the present invention requires almost no force for peeling, so that even a rectangular glass panel or metal panel having a thickness of 1.5 mm or less carrying a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less can be easily removed without damage. Effect of the Invention

[0026] As described above, the sheet of the present invention can easily bond a wafer with sufficient adhesive strength, while requiring almost no force to peel it off, so that already thinned wafers and rearrangement elements sealed in a mold can be easily handled without being damaged. In addition, the sheet of the present invention is molded from a thermosetting resin and has excellent chemical resistance, so that it is possible to use various resins for cleaning temporary adhesives.

[0027] In addition, the thinned wafer handling sheet of the present invention includes the sheet of the present invention, so that the already thinned wafer or the rearrangement element sealed in the mold can be easily handled without being damaged. Furthermore, by using the thinned wafer handling sheet of the present invention, the adhesive part has excellent chemical resistance due to the use of the thermosetting elastomer, so that it is possible to use various temporary adhesive cleaning resins. Therefore, the thinned wafer handling sheet of the present invention is particularly useful for use in, for example, a method for handling a thin wafer and a method for handling a thin device.

[0028] Furthermore, in the thin wafer handling method of the present invention, almost no force is required for peeling, so even silicon wafers with a thickness of 300 microns or less can be easily removed without damage.

[0029] Furthermore, because the thin device handling method of the present invention requires almost no force for peeling, even a rectangular glass panel or metal panel having a thickness of 1.5 mm or less carrying a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less can be easily removed without damage. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a sheet of the present invention. [Diagram 2] FIG. 1 is a schematic cross-sectional view showing an example of a thinned wafer handling sheet of the present invention. [Diagram 3] FIG. 2 is a schematic cross-sectional view showing an example of a portion where the thinned wafer handling sheet of the present invention is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] As described above, there has been a demand for the development of a tool that can easily handle already thinned wafers and rearrangement elements sealed in a mold for the thinning process of silicon wafers and compound semiconductors that are often used for purposes such as the above-mentioned three-dimensional mounting, and that has excellent chemical resistance.

[0032] As a result of intensive research into the above-mentioned problems, the inventors have found that a sheet having a plurality of cylindrical or semi-cylindrical structures having a height of 50 microns to 500 microns, or a prismatic structure having a length of 100 microns to 1 mm, and a diameter or thickness of 10 microns to 1 mm, on its surface, which are arranged at equal intervals or have a structure on its surface in which the maximum interval is less than three times the minimum interval, and which is molded from a thermosetting resin, can easily bond wafers with sufficient adhesive strength, while requiring almost no force to peel off, so that already thinned wafers and rearrangement elements sealed in a mold can be easily handled without damage, and furthermore can exhibit excellent chemical resistance, thereby completing the present invention.

[0033] In other words, the present invention is a sheet characterized in that it has on its surface a plurality of cylindrical or semi-cylindrical structures having a height of 50 microns to 500 microns and a diameter of 10 microns to 1 mm, or a prismatic structure having a length of 100 microns to 1 mm and a thickness of 10 microns to 1 mm, and the plurality of structures are arranged at equal intervals, or the plurality of structures are arranged so that the maximum spacing is less than three times the minimum spacing, and is molded from a thermosetting resin.

[0034] The present invention also provides a substrate, The sheet of the present invention laminated on the substrate; A thinned wafer handling sheet comprising:

[0035] The present invention also provides a method for handling thin wafers, comprising the steps of adhering a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less to the thinned wafer handling sheet of the present invention and then handling the wafer.

[0036] The present invention also relates to a method for handling thin devices, which comprises adhering a rectangular glass panel or metal panel having a thickness of 1.5 mm or less and carrying a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less to the thinned wafer handling sheet of the present invention and then handling the panel.

[0037] The present invention will be described in detail below, but the present invention is not limited thereto.

[0038] Fig. 1 is a schematic cross-sectional view showing an example of the sheet of the present invention. The sheet 1 shown in Fig. 1 has a plurality of structures 1a on one surface of a resin base 1b. The sheet 1, i.e., the plurality of structures 1a and the base 1b, are molded from a thermosetting resin.

[0039] The resin used in the present invention is a thermosetting resin, specifically a thermosetting elastomer, more specifically, at least one selected from the group consisting of, for example, an acrylic thermosetting elastomer, a silicone thermosetting elastomer, a urethane thermosetting elastomer, and a fluorine-based thermosetting elastomer is used.

[0040] These resins are preferably moldable into the shapes described below and do not migrate when peeled off from the object to be adhered, but there are no limitations on the scope or use.

[0041] The sheet 1 of the present invention is a resin (base portion 1b) surfaceThe sheet 1 has minute structures 1a, specifically, a plurality of structures 1a in the form of a cylinder or semi-cylinder with a height of 50 microns to 500 microns and a diameter of 10 microns to 1 mm, or a prismatic structure with a length of 100 microns to 1 mm and a thickness of 10 microns to 1 mm. In the present invention, when the structures 1a are prismatic, the thickness refers to the diameter of the circumscribed circle of the cross section of the structures 1a. The sheet 1 has, on its surface, a structure in which a plurality of structures 1a are arranged at equal intervals, or a structure in which a plurality of structures 1a are arranged such that the maximum interval 1c is less than three times the minimum interval 1d. The maximum interval 1c is greater than the minimum interval 1d.

[0042] Furthermore, as shown in FIG. 2, this sheet 1 is generally used in a form in which it is laminated to a film (substrate 2) such as a PET or polyolefin resin sheet.

[0043] The laminated sheet 10 can be used, for example, as a sheet for handling thinned wafers. The thinned wafer handling sheet 10 shown in Fig. 2 includes a substrate 2 and the sheet 1 of the present invention laminated on the substrate 2. The sheet 1 shown in Fig. 2 has the same structure as the sheet 1 shown in Fig. 1.

[0044] The structures 1a of the sheet 1 formed on the base material 2 such as a resin sheet preferably have a uniform height and a flat surface. The size and pitch (the size of the structures 1a and the interval between the structures 1a) can be selected arbitrarily, but it is desirable that they can hold the objects to be bonded, such as silicon wafers or compound semiconductor wafers on which circuits are formed.

[0045] Next, an example of the use of the thinned wafer handling sheet 10 of the present invention will be described. FIG. 3 is a schematic cross-sectional view showing an example of a portion where the thinned wafer handling sheet of the present invention is used.

[0046] After a part of the surface of the plurality of structures 1a of the sheet 1 of the thinned wafer handling sheet 10 is bonded to a frame (e.g., a metal frame) 4 such as a dicing frame, another part of the surface of the plurality of structures 1a bonds a processed thinned wafer (e.g., a silicon wafer, a compound semiconductor wafer) 3 with a carrier 5. The thinned wafer 3 to be bonded is temporarily bonded to the carrier 5 via a temporary adhesive layer 6 containing a temporary adhesive. Then, the carrier 5, for example, a glass wafer, is peeled off by a laser peeling method or the like according to the nature of the temporary adhesive of the temporary adhesive layer 6. After the carrier 5 is peeled off, the temporary adhesive residue remaining on the thinned wafer 3 is washed with an appropriate organic solvent-based cleaner, so that the thinned wafer 3 bonded on the thinned wafer handling sheet 10 according to the present invention can be taken out. Here, the sheet 1 of the present invention is molded from a thermoplastic resin, and therefore has high chemical resistance. Therefore, in the handling method using the sheet 1 of the present invention, various temporary adhesive cleaning solvents and resins can be used to remove the temporary adhesive residue.

[0047] Through the above steps, a thinned wafer 3 attached to the thinned wafer handling sheet 10 is obtained. The adhesion between the thinned wafer handling sheet 10 and the thinned wafer 3 can exhibit sufficient strength to withstand handling due to the presence of multiple structures 1a on the surface of the sheet 1. On the other hand, after handling, the thinned wafer 3 can be easily removed from the thinned wafer handling sheet 10 by applying a light force to the edge of the wafer, for example. Due to the multiple structures 1a formed on the surface of the thinned wafer handling sheet 10, almost no force is required for this peeling, and even a 300 mm silicon wafer 3 with a thickness of 300 microns or less, or even a thickness of 30 microns or less, can be easily removed without damage.

[0048] Furthermore, after the thinned wafer 3 is removed, no transfer of resin occurs on its surface, making an additional cleaning step or the like unnecessary.

[0049] In this way, the thinned wafer handling sheet 10 of the present invention can be used in a thin wafer handling method for handling, for example, a silicon wafer or compound semiconductor wafer 3 having a thickness of 300 microns or less. In the thin wafer handling method of the present invention, the silicon wafer or compound semiconductor wafer 3 can be handled after being adhered to the thinned wafer handling sheet 10 of the present invention. As a result, even a silicon wafer or compound semiconductor wafer 3 having a thickness of 300 microns or less can be easily removed without damage.

[0050] On the other hand, if the structures 1a are cylindrical or semi-cylindrical structures with a height of less than 50 microns, a height of more than 500 microns, a diameter of less than 10 microns, or a diameter of more than 1 mm, it is not possible to achieve both the adhesive strength required for handling and excellent ease of peeling.Similarly, if the structures 1a are prismatic structures with a length of less than 100 microns, a length of more than 1 mm, a thickness of less than 10 microns, or a diameter of more than 1 mm, it is not possible to achieve both the adhesive strength required for handling and excellent ease of peeling.

[0051] Furthermore, if the multiple structures 1a are arranged such that the maximum spacing exceeds three times the minimum spacing, the adhesive strength required for handling cannot be exhibited.

[0052] In the present invention, a sheet 1 made of a thermoplastic resin, preferably a thermosetting elastomer, more preferably an acrylic, silicone, urethane or fluorine-based thermosetting elastomer, processed into a desired shape is bonded to a thinned wafer, thereby making it possible to produce a thinned wafer handling sheet 10 that has excellent chemical resistance and compatibility with other processes.

[0053] The application of the thinned wafer handling sheet 10 of the present invention is not limited to a method for handling thin wafers. For example, the thinned wafer handling sheet 10 of the present invention can also be used in a method for handling thin devices. In the method for handling thin devices of the present invention, for example, a square glass panel or metal panel having a thickness of 1.5 mm or less and carrying a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less can be attached to the thinned wafer handling sheet of the present invention and then handled. As a result, even a square glass panel or metal panel having a thickness of 1.5 mm or less and carrying a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less can be easily handled without breakage.

[0054] The lower limit of the thickness of the silicon wafer or compound semiconductor wafer to be attached to and handled by the thinned wafer handling sheet 10 of the present invention is not particularly limited, but for example, a silicon wafer or compound semiconductor wafer having a thickness of 10 microns or more and 300 microns or less can be handled. Also, the lower limit of the thickness of the rectangular glass panel or metal panel to be attached to and handled by the thinned wafer handling sheet 10 of the present invention is not particularly limited, but for example, a rectangular glass panel or metal panel having a thickness of 0.1 millimeters or more and 1.5 millimeters or less carrying a silicon wafer or compound semiconductor wafer having a thickness of 10 microns or more and 300 microns or less can be handled. EXAMPLES

[0055] The present invention will be specifically described below using examples, but the present invention is not limited to these.

[0056] [Example] A thermosetting elastomer urethane resin was molded onto a PET sheet with a thickness of 100 microns to form cylindrical structures with a height of 200 microns and a diameter of 500 microns, spaced at equal intervals of 500 microns, for a total thickness of 500 microns. This produced a sheet for handling thinned wafers.

[0057] On the other hand, a 300 mm glass wafer (700 microns thick) was used as a carrier, and a 775 micron thick wafer with TSVs formed thereon was attached to the glass carrier using a UV laser peelable temporary material (SPIS-TA401+SPIS-TA501) manufactured by Shin-Etsu Chemical Co., Ltd. as a temporary adhesive layer. Next, the wafer with TSVs formed thereon was thinned to a thickness of 50 microns, TSV terminals were formed, and a SiO2 film was formed by plasma CVD using TEOS to obtain a thinned silicon wafer. The thinned wafer handling sheet obtained above was then applied to this thinned silicon wafer. stomach After forming it into a singe frame, it was glued together.

[0058] First, a UV laser was irradiated from the glass carrier surface to the front of the laminate consisting of the glass carrier, the temporary adhesive layer, the thinned silicon wafer, and the thinned wafer handling sheet to peel off the glass carrier. After that, the temporary adhesive resin residue remaining on the silicon wafer was dissolved and cleaned with a cleaner SPIS-TA-Cleaner-25 manufactured by Shin-Etsu Chemical Co., Ltd.

[0059] At this time, no abnormality such as peeling, floating, etc. was observed in the thinned wafer handling sheet supporting the thinned silicon wafer. In other words, the adhesion between the thinned wafer handling sheet and the thinned silicon wafer was strong enough to withstand handling of the thin wafer.

[0060] Finally, when the thinned wafer handling sheet was peeled off from the edge of the thinned silicon wafer using the back side of the sheet, the sheet peeled off easily, and no damage such as cracks occurred on the 50 micron thick wafer, and no resin adhesive residue was left behind.

[0061] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. a structure having on its surface a plurality of cylindrical or semi-cylindrical structures having a height of 50 microns to 500 microns and a diameter of 10 microns to 1 mm, or a prismatic structure having a length of 100 microns to 1 mm and a thickness of 10 microns to 1 mm, the plurality of structures being equally spaced from one another, or a structure having on its surface a plurality of structures being arranged such that the maximum distance between the structures is less than three times the minimum distance between the structures, the structure being molded from a thermosetting resin; A sheet used for handling thinned wafers or mold-encapsulated repositionable elements.

2. A structure having on its surface a plurality of cylindrical or semi-cylindrical structures having a height of 50 microns to 500 microns and a diameter of 10 microns to 1 mm, or a prismatic structure having a length of 100 microns to 1 mm and a thickness of 10 microns to 1 mm, the plurality of structures being equally spaced apart, or the plurality of structures being arranged such that the maximum spacing is less than three times the minimum spacing, the structure comprising a thermosetting elastomer; A sheet used for handling thinned wafers or mold-encapsulated repositionable elements.

3. 3. The sheet according to claim 2, wherein the thermosetting elastomer is at least one selected from the group consisting of an acrylic thermosetting elastomer, a silicone thermosetting elastomer, a urethane thermosetting elastomer, and a fluorine-based thermosetting elastomer.

4. A substrate; The sheet according to any one of claims 1 to 3 laminated on the substrate; A handling sheet comprising:

5. A handling method comprising the steps of: adhering a thinned wafer or a mold-sealed relocation element having a thickness of 300 microns or less to the sheet according to any one of claims 1 to 3 and then handling the same.

6. A method for handling a thin device, comprising the steps of: bonding a rectangular glass panel or metal panel having a thickness of 1.5 mm or less and carrying a silicon wafer or compound semiconductor wafer having a thickness of 300 microns or less to the sheet according to any one of claims 1 to 3, and then handling the panel.

7. A method for removing a thinned wafer, comprising peeling off the carrier from the thinned wafer while the thinned wafer supported by the carrier is adhered to a sheet described in any one of claims 1 to 3.

8. A method for removing a molded sealed relocation element, characterized in that the molded sealed relocation element supported by a carrier is adhered to a sheet described in any one of claims 1 to 3, and the carrier is peeled off from the molded sealed relocation element.

9. A method for manufacturing a extracted thinned wafer, comprising peeling off the carrier from the thinned wafer while the thinned wafer supported by the carrier is adhered to a sheet described in any one of claims 1 to 3.

10. A method for producing a molded sealed relocation element that is extracted, comprising: peeling the carrier from the molded sealed relocation element while the molded sealed relocation element supported by the carrier is adhered to a sheet described in any one of claims 1 to 3.

11. A method for manufacturing a package, comprising a step of peeling off a thinned wafer or a molded sealed relocation element supported by a carrier while the carrier or the molded sealed relocation element is adhered to a sheet described in any one of claims 1 to 3.

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