Method for manufacturing a laminate, laminate, and method for manufacturing a semiconductor package

Abstract

The present invention relates to a method for producing a multilayer body, said method comprising: a step for forming a multilayer body precursor which sequentially comprises a first glass substrate, a thermosetting resin layer and a second glass substrate that has a higher average thermal expansion coefficient than the first glass substrate in this order; a step for obtaining a resin layer by subjecting the multilayer body precursor to a heat treatment, thereby thermally curing the thermosetting resin layer, while causing the first glass substrate and the second glass substrate to expand; and a step for obtaining a multilayer body having a warp by cooling the multilayer body precursor, which has been subjected to thermal curing.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a laminate, a laminate, and a method for manufacturing a semiconductor package.

Background Art

[0002] A semiconductor device including an integrated circuit or the like is mounted by being electrically connected to a redistribution layer (RDL) by a bonding wire or solder balls, etc., and is further sealed with resin to form a semiconductor package. A semiconductor package is manufactured, for example, by the following method. First, after forming a redistribution layer on a glass substrate, a semiconductor device is electrically connected to the redistribution layer by a bonding wire or solder balls, etc. Then, the semiconductor device is sealed with resin. And a semiconductor package is obtained by peeling the redistribution layer on which the resin-sealed semiconductor device is mounted from the glass substrate. In consideration of deformation of the substrate due to heat in the manufacturing process of the semiconductor package, a glass substrate having warpage as described in Patent Document 1 is used for the glass substrate used in the manufacture of the semiconductor package. Patent Document 1 describes a glass substrate having a warpage of 2 to 300 μm and an inclination angle due to warpage of 0.0004 to 0.12°.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The glass substrate of Patent Document 1 described above has warpage formed through a forming process and a slow cooling process. Although the slow cooling temperature of the slow cooling process is adjusted to adjust the warpage and the inclination angle due to warpage, it is not easy to adjust the warpage amount, etc. Accordingly, an object of the present invention is to provide a method for manufacturing a laminate that can easily manufacture a laminate having warpage and maintaining the warpage even after being exposed to high temperatures. Another object of the present invention is to provide a laminate having warpage and a method for manufacturing a semiconductor package.

Means for Solving the Problems

[0005] As a result of intensive studies, the present inventors have found that the above object can be achieved by the following configuration. An aspect of the present invention includes a step of forming a precursor laminate having, in this order, a first glass substrate, a thermosetting resin layer, and a second glass substrate having a larger average thermal expansion coefficient than the first glass substrate; a step of subjecting the precursor laminate to a heat treatment to thermally cure the thermosetting resin layer while expanding the first glass substrate and the second glass substrate to obtain a resin layer; and a step of cooling the heat-treated precursor laminate to obtain a laminate having warpage. The present invention provides a method for manufacturing a laminate. It is preferable that the difference in average thermal expansion coefficient between the first glass substrate and the second glass substrate is 0.3 to 2.0 ppm / °C. The temperature of the thermosetting resin layer during thermosetting is preferably 400°C or lower. The thermosetting of the thermosetting resin layer is preferably performed at a temperature 20°C or higher than the thermosetting start temperature of the thermosetting resin layer.

[0006] An aspect of the present invention provides a laminate having, in this order, a first glass substrate, a resin layer, and a second glass substrate, wherein the average thermal expansion coefficient of the second glass substrate is larger than that of the first glass substrate, and the laminate has warpage. It is preferable that the outer surface of the first glass substrate is the surface on which an electronic device is formed. It is preferable that the first glass substrate, the resin layer, and the second glass substrate are curved so that the outer surface of the first glass substrate is convex, and an electronic device is disposed on the curved first glass substrate. It is preferable that the difference in average thermal expansion coefficient between the first glass substrate and the second glass substrate is 0.3 to 2.0 ppm / °C. The laminate preferably has a total thickness of 0.3 to 3.0 mm. The amount of warp of the laminate is preferably more than 0 μm and 500 μm or less. The amount of warp of the laminate after heating at 250° C. for 3 hours is preferably more than 0 μm and 500 μm or less. An aspect of the present invention provides a method for manufacturing a semiconductor package, including: preparing a laminate having, in this order, a first glass substrate, a resin layer, and a second glass substrate, and having a warp, wherein an average coefficient of thermal expansion of the second glass substrate is larger than that of the first glass substrate; forming a rewiring layer on an outer surface of the first glass substrate; electrically connecting a semiconductor device to the rewiring layer; encapsulating the semiconductor device with a resin; and peeling the rewiring layer on which the semiconductor device encapsulated with the resin is mounted from the first glass substrate.

Advantages of the Invention

[0007] According to the present invention, a laminate having a warp and maintaining the warp even after being exposed to a high temperature can be easily manufactured. Further, a laminate having a warp can be provided. Furthermore, a semiconductor package can be manufactured.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are exemplary for explaining the present invention and are not limited to the following embodiments. Various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. A numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0010] The method for manufacturing a laminate of the present invention includes a step of forming a precursor laminate having, in this order, a first glass substrate, a thermosetting resin layer, and a second glass substrate having a higher average thermal expansion coefficient than the first glass substrate, and a step of subjecting the precursor laminate to a heat treatment to expand the first glass substrate and the second glass substrate while thermosetting the thermosetting resin layer to obtain a resin layer, and then cooling the precursor laminate that has been subjected to the thermosetting treatment. Thereby, a laminate having a warp and having a resin layer disposed between the first glass substrate and the second glass substrate is obtained. By subjecting the precursor laminate to a heat treatment to expand the first glass substrate and the second glass substrate while forming and cooling the resin layer, a laminate having a warp can be formed at a temperature sufficient to cure the thermosetting resin. Therefore, it is not necessary to increase the temperature. Furthermore, in the laminate having a warp, the resin layer is thermoset and the warp is maintained even after being exposed to a high temperature. Hereinafter, the method for manufacturing a laminate will be described.

[0011] [Method for Manufacturing a Laminate] [An Example of the Method for Manufacturing a Laminate] Figs. 1(a) to 1(d) are schematic cross-sectional views showing the manufacturing method of the laminate according to the embodiment of the present invention in the order of steps, and Fig. 2 is a schematic cross-sectional view of an example of the laminate according to the embodiment of the present invention. The laminate to be manufactured (see Fig. 2) has warpage, and a resin layer is disposed between two glass substrates, and has a first glass substrate 14 (see Fig. 1(b)) and a second glass substrate 10 (see Fig. 1(b)). Both the first glass substrate 14 (see Fig. 1(b)) and the second glass substrate 10 (see Fig. 1(b)) are disks. The first glass substrate 14 and the second glass substrate 10 have different average thermal expansion coefficients, and the second glass substrate 10 has a larger average thermal expansion coefficient than the first glass substrate 14. First, as shown in Fig. 1(a), a thermosetting resin layer 12 is formed on one surface (surface 10a) of the second glass substrate 10. In Fig. 1(a), the thermosetting resin layer 12 is in an uncured state. Next, as shown in Fig. 1(b), the first glass substrate 14 is disposed on the surface 12a opposite to the surface of the thermosetting resin layer 12 on which the second glass substrate 10 is disposed. Thereby, a precursor laminate 16 having the thermosetting resin layer 12 disposed between the first glass substrate 14 and the second glass substrate 10 is formed. Note that the precursor laminate 16 may have its periphery chamfered. The precursor laminate 16 may be further ground and polished on the outer surface 14a of the first glass substrate 14 and the surface 10b of the second glass substrate 10. Thereby, the thickness of the precursor laminate 16 and the TTV (Total Thickness Variation) are adjusted.

[0012] Next, the precursor laminate 16 is heat-treated. As shown in FIG. 1(c), while expanding the first glass substrate 14 and the second glass substrate 10, the thermosetting resin layer 12 is cured to obtain the resin layer 13. The heat treatment of the precursor laminate 16 is, for example, carried out in a nitrogen atmosphere. After raising the temperature from 25°C to 250°C at a rate of 10°C / min, it is held at 250°C for 30 minutes. The first glass substrate 14 and the second glass substrate 10 have different average thermal expansion coefficients. Since the second glass substrate 10 has a larger average thermal expansion coefficient than the first glass substrate 14, during the heat treatment, as shown in FIG. 1(c), the second glass substrate 10 expands more than the first glass substrate 14. Also, due to the heat treatment, the thermosetting resin layer 12 is cured to become the resin layer 13. Next, after holding the precursor laminate 16 at 250°C for 30 minutes, it is cooled from 250°C to 150°C at a rate of -10°C / min. During cooling, as shown in FIG. 1(d), the first glass substrate 14 and the second glass substrate 10 are deformed such that the outer surface 14a of the first glass substrate 14 becomes convex. That is, the first glass substrate 14 and the second glass substrate 10 are warped in the laminated state. Thereby, a warped precursor laminate 16 is obtained.

[0013] After cooling, a laminate 30 having the first glass substrate 14, the resin layer 13, and the second glass substrate 10 in this order as shown in FIG. 2 and having warpage is obtained. The laminate 30 maintains the warpage even after being exposed to a high temperature, such as when being heated during the manufacture of a semiconductor package as described later. The laminate 30 shown in FIG. 2 has a circular outer shape. In the above description, the first glass substrate 14 and the second glass substrate 10 are each a disk, but the shape is not particularly limited and may be, for example, rectangular. Also, the first glass substrate 14 and the second glass substrate 10 are preferably similar in shape in order to be laminated and deformed to form the laminate 30. Also, when manufacturing the laminate 30, instead of using a disk-shaped glass substrate, for example, a rectangular first glass substrate 14 and a second glass substrate 10 are used. After forming the precursor laminate, it may be cut into a circular shape and chamfered, ground, and polished to obtain a precursor laminate having a circular outer shape.

[0014] <Stacked body> As described above, the stacked body 30 shown in FIG. 2 has a circular outer shape. For example, when the surface 10b of the second glass substrate 10 is placed on the plane B in contact with the plane B, the first glass substrate 14, the resin layer 13, and the second glass substrate 10 are curved so that the outer surface 14a of the first glass substrate 14 becomes convex. The outer diameter of the first glass substrate 14 in the warped state when the surface 10b of the second glass substrate 10 is placed on the plane B in contact with the plane B as described above is the diameter D of the stacked body 30. The diameter D is not particularly limited, but can be approximately the same size as a semiconductor wafer, for example, 8 inches or 12 inches. FIG. 3 is a schematic cross-sectional view showing an example of a usage example of the stacked body according to the embodiment of the present invention. In FIG. 3, the same components as the stacked body 30 shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted. As described above, the first glass substrate 14, the resin layer 13, and the second glass substrate 10 are curved so that the outer surface 14a of the first glass substrate 14 becomes convex. The outer surface 14a of the first glass substrate 14 means the surface on the opposite side of the surface on which the resin layer 13 of the first glass substrate 14 is disposed.

[0015] Also, considering the handling in the transfer process and the peeling of the rewiring layer 42, the total thickness h (FIG. 2) of the stacked body 30 is preferably 0.3 to 3.0 mm, more preferably 0.5 to 2.0 mm. The total thickness h of the stacked body 30 can be measured using a spectral laser displacement meter. Also, the warpage amount of the stacked body 30 is preferably more than 0 μm and 500 μm or less, more preferably 50 to 300 μm. When the warpage amount of the stacked body 30 is more than 0 μm, the warpage correction effect in the packaging process of the electronic device is sufficient. When the warpage amount of the stacked body 30 is 500 μm or less, it becomes easier to hold (chuck) the substrate in the packaging process of the electronic device. The warpage amount of the laminate 30 after heating at 250°C for 3 hours is preferably more than 0 μm and 500 μm or less, more preferably 50 to 300 μm. If the warpage amount of the laminate 30 after heating at 250°C for 3 hours is more than 0 μm and 500 μm or less, the warpage is maintained even after the laminate 30 is exposed to high temperatures, such as in the packaging process of electronic devices, and it can be repeatedly used in the manufacture of semiconductor packages. Note that "after heating at 250°C for 3 hours" means the state after heating at 250°C for 3 hours in a nitrogen atmosphere and then the laminate has reached room temperature (25°C).

[0016] (Semiconductor Package and Method for Manufacturing the Same) As shown in FIG. 3, a semiconductor package 40 is provided on the outer surface 14a of the curved first glass substrate 14. The semiconductor package 40 has, for example, an electronic device 44 mounted on a redistribution layer 42. The electronic device 44 is disposed on the curved first glass substrate 14. The surface of the first glass substrate 14 opposite to the surface on which the resin layer 13 is disposed, that is, the outer surface 14a of the first glass substrate 14, is the surface on which the electronic device 44 is formed. The redistribution layer 42 and the electronic device 44 are electrically connected by bonding wires, solder balls, or the like. The electronic device 44 is encapsulated with a resin 46. The redistribution layer 42 is formed on the outer surface 14a of the first glass substrate 14. The semiconductor package 40 is taken out by peeling the redistribution layer 42 from the outer surface 14a of the first glass substrate 14. The electronic device 44 is a semiconductor device having an integrated circuit or the like, and specifically, for example, MEMS (Micro Electro Mechanical Systems), ASIC (Application Specific Integrated Circuit), or the like. The resin 46 is a sealing resin for encapsulating the electronic device 44, and those used for semiconductor packages can be appropriately used. As the resin 46, for example, a known thermosetting resin such as an epoxy resin mixed with fine silica particles is used.

[0017] (Measurement of warpage amount) Figs. 4(a) and (b) are schematic cross-sectional views for explaining a method of measuring the warpage amount of the laminate according to an embodiment of the present invention. As shown in Fig. 4(a), the warpage amount of the laminate 30 is measured by arranging the laminate 30 with the surface 10b of the second glass substrate 10 facing the surface 50a of the precision surface plate 50. A laser displacement meter 52 is used for measuring the warpage amount. Laser light L is irradiated from the laser displacement meter 52 onto the outer surface 14a of the first glass substrate 14, and the height from the surface 50a of the precision surface plate 50 to the outer surface 14a of the first glass substrate 14 irradiated with the laser light L is measured. For example, the laser light L is irradiated at intervals of 3 mm along one direction parallel to the surface 50a of the precision surface plate 50, and the height at each irradiation position is measured. Thereby, the maximum height hc in the plane of the first glass substrate 14 and the height hi at the end are obtained. In the thickness direction of the laminate 30, a value (hc - hi) obtained by subtracting the height hi at the end of the first glass substrate 14 from the maximum height hc in the plane of the first glass substrate 14 is calculated as the warpage amount. As shown in Fig. 4(a), when the laminate 30 has a convex shape, that is, when the end of the surface 10b of the second glass substrate 10 is in contact with the surface 50a of the precision surface plate 50 and the center is not in contact with the surface 50a of the precision surface plate 50, the warpage amount of the laminate 30 is positive. On the other hand, as shown in Fig. 4(b), when the laminate 30 has a concave shape, that is, when the end of the surface 10b of the second glass substrate 10 is not in contact with the surface 50a of the precision surface plate 50 and the center is in contact with the surface 50a of the precision surface plate 50, the warpage amount of the laminate is the difference between the minimum height hm in the plane and the height hi at the end. In this case, the warpage amount is negative.

[0018] [Manufacturing method of laminated substrate] As described above, the manufacturing method of the laminated substrate includes at least a step of forming a precursor laminate having two glass substrates and a thermosetting resin layer disposed between the two glass substrates (precursor laminate forming step), and a step of thermosetting the thermosetting resin layer to form a resin layer (forming step). Hereinafter, each of the above steps will be described.

[0019] (Precursor laminate formation step) <Thermosetting resin layer formation step> In the thermosetting resin layer formation step, as the thermosetting resin layer, for example, a layer of thermosetting silicone is formed on the surface 10a of the second glass substrate 10. The method for forming the thermosetting resin layer (layer of thermosetting silicone) is not particularly limited, and for example, spray coating method, die coating method, spin coating method, dip coating method, roll coating method, bar coating method, screen printing method, and gravure coating method are used.

[0020] <Lamination step> The lamination step is a step of laminating the first glass substrate 14 on the surface 12a of the thermosetting resin layer 12. Specific examples of the method for laminating the first glass substrate 14 on the surface 12a of the thermosetting resin layer 12 include a method of overlapping the first glass substrate 14 on the surface 12a of the thermosetting resin layer 12 in an atmospheric pressure environment. If necessary, after overlapping the first glass substrate 14 on the surface 12a of the thermosetting resin layer 12, the first glass substrate 14 may be pressure-bonded to the thermosetting resin layer using a roll or a press. Pressure-bonding by a roll or a press is preferable because bubbles mixed between the thermosetting resin layer 12 and the first glass substrate 14 can be removed relatively easily. Pressing by a vacuum lamination method or a vacuum press method is preferable because it can suppress the mixing of bubbles and achieve good adhesion. By pressing under vacuum, there is also an advantage that even if minute bubbles remain, it is difficult for the bubbles to grow by heat treatment. When laminating the first glass substrate 14 on the surface 12a of the thermosetting resin layer 12, it is preferable to sufficiently clean the surface of the first glass substrate 14 that contacts the thermosetting resin layer and perform the lamination in an environment with a high degree of cleanliness. In the precursor laminate formation step, after forming the thermosetting resin layer 12 on the surface of the first glass substrate 14 in the thermosetting resin layer formation step, the second glass substrate 10 may be laminated on the surface of the thermosetting resin layer 12 in the lamination step.

[0021] <Chamfering step> The chamfering process is a process of chamfering the periphery of the precursor laminate 16. The chamfering method is not particularly limited, and known methods such as a method using a chamfering machine for a glass substrate can be used. Also, after chamfering, the front surface, back surface, etc. of the precursor laminate 16 may be ground using a grinding machine or the like and polished using a polishing machine. By performing chamfering or the like, it is possible to prevent the precursor laminate 16 from damaging the apparatus or the like. Also, by grinding and polishing the front surface, back surface, etc. of the precursor laminate 16, the thickness of the precursor laminate 16 and the TTV (Total Thickness Variation) can be adjusted.

[0022] (Forming process) The forming process is a process of thermally curing the thermosetting resin layer 12 by subjecting the precursor laminate 16 to a heat treatment to form the resin layer 13. As described above, when the precursor laminate 16 is subjected to a heat treatment, as shown in FIG. 1(c), the second glass substrate 10 expands more than the first glass substrate 14. By the heat treatment, the thermosetting resin layer 12 is cured to become the resin layer 13. Next, by cooling, as shown in FIG. 1(d), the first glass substrate 14 and the second glass substrate 10 are curved, and the laminate 30 (see FIG. 2) is formed. When the thermosetting resin layer 12 is composed of a thermosetting silicone, it is cured by heat treatment to form a silicone resin layer as the resin layer 13. As the thermosetting silicone, for example, a condensation reaction type silicone and an addition reaction type silicone are used. The silicone resin layer will be described later. The conditions for the heat curing treatment are, for example, the temperature conditions for heat curing are preferably 50 to 400°C, more preferably 100 to 300°C. The heating time is preferably 10 to 300 minutes, more preferably 20 to 120 minutes. The temperature of the thermosetting resin layer during heat curing is preferably 400°C or lower, more preferably 300°C or lower. Thereby, it is possible to suppress the temperature during molding from becoming high. Further, the thermosetting of the thermosetting resin layer is preferably carried out at a temperature that is 20 °C or more, more preferably 50 °C or more higher than the thermosetting start temperature of the thermosetting resin layer. By thermosetting the thermosetting resin layer at the above temperature, it can be surely thermoset, and a resin layer can be obtained. The thermosetting start temperature of the thermosetting resin layer is preferably 40 °C or more and 300 °C or less, more preferably 80 °C or more and 200 °C or less. If the thermosetting start temperature of the thermosetting resin layer is too low, the curing of the thermosetting resin layer may proceed before the molding process, and it may be impossible to obtain a laminate with a desired amount of warp after the molding process. On the other hand, if the thermosetting start temperature of the thermosetting resin layer is too high, the temperature during molding may become high. Regarding the definition of the thermosetting start temperature, differential scanning calorimetry (DSC) is performed on the thermosetting resin under the condition of a heating rate of 10 °C / min, and the intersection of the baseline of the DSC curve and the tangent at the inflection point of the peak is defined as the thermosetting start temperature.

[0023] Hereinafter, the laminate will be described. <First Glass Substrate, Second Glass Substrate> As described above, the first glass substrate and the second glass substrate have different average thermal expansion coefficients, and the average thermal expansion coefficient of the second glass substrate is larger than that of the first glass substrate. The glass constituting the first glass substrate and the second glass substrate is not particularly limited. As the type of glass, alkali-free borosilicate glass, borosilicate glass, soda-lime glass, high-silica glass, and other oxide-based glasses mainly composed of silicon oxide are preferable. As the oxide-based glass, a glass having a silicon oxide content of 40 to 90% by mass in terms of oxide is preferable. As an example of the glass plate, more specifically, a glass plate made of alkali-free borosilicate glass (product name "AN100" manufactured by AGC Inc.) can be mentioned. Also, product names "FL900" and "FL960" manufactured by AGC Inc. can be used. A combination of glass substrates with different average thermal expansion coefficients is used for the first glass substrate and the second glass substrate. As an example of a method for manufacturing a glass plate, a method of melting a glass raw material and forming the molten glass into a plate shape is generally cited. Such a forming method may be a common one, and examples include the float method, the fusion method, and the slot down draw method.

[0024] As described above, the glass constituting the first glass substrate and the second glass substrate is not particularly limited, but the first glass substrate 14 and the second glass substrate 10 have different average thermal expansion coefficients, and the difference in the average thermal expansion coefficients between the first glass substrate and the second glass substrate is preferably 0.3 to 2.0 ppm / °C. From the viewpoint of obtaining a sufficient amount of warpage, the difference in the average thermal expansion coefficients is more preferably 0.6 to 1.5 ppm / °C. When the first glass substrate and the second glass substrate are the same glass substrate, the difference in the average thermal expansion coefficients is 0 ppm / °C. When the difference in the average thermal expansion coefficients is 0.3 ppm / °C or more, a sufficient amount of warpage can be obtained. On the other hand, when the difference in the average thermal expansion coefficients is 2.0 ppm / °C or less, cracking of the first glass substrate or the second glass substrate due to heating in the forming process or the device manufacturing process can be suppressed. The average thermal expansion coefficients of the first glass substrate and the second glass substrate are the average thermal expansion coefficients at a temperature of 30 to 220°C measured using a differential thermal dilatometer (TMA) in accordance with the method specified in JIS R3102 (1995). The thickness of the first glass substrate and the thickness of the second glass substrate are each preferably 0.1 to 1.8 mm, and more preferably 0.15 to 1.0 mm from the viewpoint of preventing cracking or the like due to heating in the laminate manufacturing process, the forming process, or the device manufacturing process. The preferred ranges of the thickness of the first glass substrate and the thickness of the second glass substrate described above indicate the preferred ranges of both the thickness before laminate manufacturing and the thickness in the laminate. The thicknesses of the first glass substrate and the second glass substrate can be measured using a spectral laser displacement meter.

[0025] <Resin layer> The resin layer 13 laminates the first glass substrate 14 and the second glass substrate 10 and holds the deformed state. With the first glass substrate and the second glass substrate in a deformed state, the thermosetting resin layer 12 is cured to obtain the resin layer 13. Thereby, the resin layer 13 holds the deformed state of the first glass substrate 14 and the second glass substrate 10. The thickness of the resin layer 13 is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. On the other hand, the thickness of the resin layer 13 is preferably more than 1 μm, more preferably 4 μm or more. The above thickness is obtained by measuring the thickness of the resin layer 13 at any 5 or more positions with a contact-type film thickness measuring device and calculating their arithmetic mean.

[0026] <Silicone resin layer> The resin layer 13 is a silicone resin layer if the thermosetting resin layer 12 is composed of a thermosetting silicone. The silicone resin layer is an example of the layer constituting the resin layer 13. The silicone resin layer mainly consists of a silicone resin. The structure of the silicone resin is not particularly limited. The silicone resin is usually obtained by curing (crosslinking and curing) a curable silicone that can become a silicone resin by a curing treatment. Specific examples of the curable silicone include a condensation reaction type silicone and an addition reaction type silicone. The weight average molecular weight of the curable silicone is preferably 5,000 to 60,000, more preferably 5,000 to 30,000.

[0027] The silicone resin layer is formed by applying a curable composition containing a curable silicone that becomes a silicone resin to form a thermosetting resin layer and by heat treatment. In addition to the curable silicone, the curable composition may contain a solvent, a platinum catalyst (when using an addition reaction type silicone as the curable silicone), a leveling agent, and a metal compound, etc. Specific examples of the metal element contained in the metal compound include 3d transition metals, 4d transition metals, lanthanoid series metals, bismuth, aluminum, and tin. The content of the metal compound is adjusted as appropriate. Examples of the resin layer 13 include those containing acrylic resins, novolak resins, naphthoxane resins, hydrocarbon resins, polyimide resins, elastomers, and the like. The resin layer 13 can be composed of, for example, hydrocarbon resins, acrylic-styrene resins, maleimide resins, elastomers, etc., or resins obtained by combining these.

Examples

[0028] The present invention will be specifically described below with reference to examples and the like, but the present invention is not limited by these examples. Examples 1 to 10 described later are examples, and Examples 11 to 14 are comparative examples. In Examples 1 to 13, all were laminates having a circular outer shape. Example 14 was a single glass substrate having a circular outer shape.

[0029] <Evaluation> 《Heat resistance test》 The circular laminate was placed in an inert gas oven and heated at 250°C for 3 hours in a nitrogen atmosphere. After confirming that the circular laminate taken out of the oven had reached room temperature (25°C), the amount of warpage was measured. The method for measuring the amount of warpage will be described later.

[0030] <Preparation of curable silicone and curable composition> 《Preparation of curable silicone》 A curable silicone was obtained by mixing organohydrogensiloxane and alkenyl group-containing siloxane. The composition of the curable silicone had a molar ratio of M units, D units, and T units of 9:59:32, a molar ratio of methyl groups and phenyl groups in the organic groups of 44:56, a molar ratio of all alkenyl groups to hydrogen atoms bonded to all silicon atoms (hydrogen atom / alkenyl group) of 0.7, and an average number of OX groups of 0.1. The average number of OX groups is a numerical value representing the average number of OX groups (X is a hydrogen atom or a hydrocarbon group) bonded to one Si atom.

[0031] 《Preparation of curable composition 1》 A solution obtained by mixing diethylene glycol diethyl ether (“Hysorb EDE”, manufactured by Toho Chemical Industry Co., Ltd.) (1986 g) and a curable silicone (2997 g) was added with Platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane (CAS No. 68478-92-2) so that the content of platinum element with respect to the curable silicone became 120 ppm, to obtain a mixture A. Methylphenyl-modified silicone (“AP 1000”, manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) (4.5 g) was mixed into the mixture A, and the resulting mixed solution was filtered using a filter with a pore size of 0.45 μm to obtain a curable composition.

[0032] Hereinafter, Examples 1 to 14 will be described. <Examples 1 to 12> 《Preparation of Glass Substrate》 The glass substrates described in Table 1 were prepared as the first glass substrate and the second glass substrate. The size of the first glass substrate was 450 mm × 450 mm, and the size of the second glass substrate was 500 mm × 500 mm. The glass substrates were washed using an aqueous glass cleaner (“PK-LCG213”, manufactured by Parker Corporation), and then washed with pure water.

[0033] 《Measurement Method for Physical Properties of Glass Substrate》 (Average Coefficient of Thermal Expansion) In accordance with the method specified in JIS R3102 (1995), the average coefficient of thermal expansion from 30 to 220 °C was measured using a differential thermal dilatometer (TMA). (Thickness) The plate thickness of the glass substrate was measured using a spectral laser displacement meter (manufactured by Keyence Corporation).

[0034] 《Preparation of Precursor Laminate》 The prepared curable composition was applied to a second glass substrate using a die coater, and heated at 120°C for 3 minutes using a hot plate to form a silicone resin layer with a thickness of 10 μm. Subsequently, the silicone resin layer surface on the second glass substrate and the first glass substrate were bonded together using a bonding apparatus to produce a precursor laminate. After forming scribe lines on both surfaces of the precursor laminate using a glass cutter, stress was applied to the ends of the precursor laminate to cut it, obtaining a circular precursor laminate with a diameter of 300 mm. Next, the ends of the circular precursor laminate were chamfered using a glass grinding wheel. Thereafter, one or both surfaces of the circular precursor laminate were ground and polished to obtain a desired plate thickness.

[0035] 《Laminating of the laminate》 The obtained circular precursor laminate was placed in an inert gas oven and heated in a nitrogen atmosphere. After heating from 25°C to 250°C at a rate of 10°C / min, it was held at 250°C for 30 minutes and then cooled from 250°C to 150°C at a rate of -10°C / min. When it was cooled to 150°C, air was introduced into the inert gas oven, and the circular precursor laminate was taken out of the oven to obtain a laminate with a circular outer shape. After confirming that the circular laminate taken out of the oven reached room temperature (25°C), the total thickness of the laminate and the amount of warpage of the laminate were measured.

[0036] <Example 13> A silicon nitride film 19 (SiN film) was formed on one side of the first glass substrate 14 (see FIG. 5) washed by the same procedure as in Example 1 using a sputtering apparatus to obtain a laminate with a circular outer shape. The thickness of the silicon nitride film 19 (see FIG. 5) was 200 nm. After forming the silicon nitride film 19, the total thickness of the laminate and the amount of warpage of the laminate were measured. Subsequently, a heat resistance test similar to that in Example 1 was carried out, and the amount of warpage after the heat resistance test was measured. <Example 14> When manufacturing the first glass substrate, in the process of shaping molten glass into a plate shape and gradually cooling it, by adjusting the temperature of the central part of the glass ribbon in the width direction of the glass ribbon perpendicular to the advancing direction of the glass ribbon and the temperature of the end part of the glass ribbon, a first glass substrate 60 (see Fig. 6) having warpage was manufactured. After confirming that the first glass substrate 60 (see Fig. 6) had been cooled to room temperature, the amount of warpage was measured. Subsequently, a heat resistance test similar to Example 1 was carried out, and the amount of warpage after the heat resistance test was measured. In Example 14, the plate thickness of the first glass substrate 60 (see Fig. 6) was set to the total thickness shown in Table 1 below.

[0037] <Regarding the measurement of the amount of warpage> A method for measuring the amount of warpage of the laminate will be described with reference to Figs. 4(a) and (b). Figs. 4(a) and (b) schematically show the state of warpage of the laminate. The laminate 30 was placed on the surface 50a of the precision surface plate 50 with the first glass substrate 14 on the upper side and the second glass substrate 10 on the lower side. The height in the thickness direction of the outer surface 14a of the first glass substrate 14 was measured at 3 mm intervals along a direction parallel to the surface 50a of the precision surface plate 50 by a non-contact laser displacement meter 52. The amount of warpage was calculated as the value obtained by subtracting the height of the end part of the first glass substrate 14 from the maximum height in the plane of the first glass substrate 14 in the thickness direction of the laminate 30. As shown in Fig. 4(a), the amount of warpage of the laminate 30 when the laminate 30 is convex is taken as positive, and as shown in Fig. 4(b), the amount of warpage of the laminate 30 when the laminate 30 is concave is taken as negative.

[0038] In Examples 11 and 12, the laminate was placed on the surface 50a of the precision surface plate 50 with the surface on which the electronic device is formed on the upper side. In Example 13, as shown in Fig. 5, the first glass substrate 14 with a silicon nitride film 19 was placed on the surface 50a of the precision surface plate 50 with the non-film-forming surface of the silicon nitride film 19 on the upper side and the film-forming surface side on the lower side. The height in the thickness direction of the non-film-forming surface side was measured by the laser displacement meter 52, and the amount of warpage was calculated as the value obtained by subtracting the height of the end part from the maximum height in the plane of the substrate. In Example 14, as shown in FIG. 6, similar to the laminate, the first glass substrate 60 was placed on the surface 50a of the precision surface plate 50, and the amount of warpage was calculated by the laser displacement meter 52 as the value obtained by subtracting the height of the end portion from the maximum height in the plane of the first glass substrate 60. In FIGS. 5 and 6, the same components as those shown in FIGS. 4(a) and (b) are denoted by the same reference numerals, and detailed description thereof is omitted. Also, the total thickness of the laminate was measured by a spectral laser displacement meter (manufactured by Keyence Corporation).

[0039] [Table 1]

[0040] <Summary of Evaluation Results> As shown in Table 1 above, in Examples 1 to 10 that satisfy the predetermined requirements, the change in the amount of warpage before and after the heat resistance test was small and the heat resistance was excellent. In Examples 11 and 12, the first glass substrate and the second glass substrate were made of the same glass substrate, and there was no difference in the average coefficient of thermal expansion, and a laminate having a sufficient amount of warpage could not be produced. In Example 13, a glass substrate warped by a silicon nitride film (SiN film) can be produced, but the stress of the SiN film was relaxed by heating in the heat resistance test, and the amount of warpage became small. Therefore, in Example 13, warpage during the semiconductor process cannot be suppressed. In Example 14, there is no change in the amount of warpage before and after the heat resistance test and there is no problem, but since it is molded at a high temperature, it is not easy to produce a glass substrate having high molding accuracy and warpage. It is disadvantageous in terms of production efficiency such as the production amount per unit time and manufacturing cost.

[0041] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application No. 2020-133874 filed on August 6, 2020, the content of which is incorporated herein by reference. [Explanation of Reference Numerals]

[0042] 10 Second glass substrate 10a, 10b, 12a, 14a, 50a surfaces 12 Thermosetting resin layer 13 Resin layer 14 First glass substrate 16 Precursor laminate 19 Silicon nitride film 30 Laminate 40 Semiconductor package 42 Rewiring layer 44 Electronic device 50 Precision surface plate 52 Laser displacement meter 60 First glass substrate B Plane D Diameter L Laser beam h Total thickness hc Maximum height in plane hi Height of end portion hm Minimum height in plane

Claims

1. Forming a precursor laminate having, in this order, a first glass substrate, a thermosetting resin layer, and a second glass substrate having a higher average coefficient of thermal expansion than the first glass substrate; Subjecting the precursor laminate to a heat treatment to thermally cure the thermosetting resin layer to obtain a resin layer while expanding the first glass substrate and the second glass substrate; Cooling the precursor laminate subjected to the heat curing treatment to obtain a laminate having warpage, A method for manufacturing a laminate, wherein the difference in average coefficient of thermal expansion between the first glass substrate and the second glass substrate is 0.3 to 2.0 ppm / °C.

2. The method for manufacturing a laminate according to claim 1, wherein the temperature of the thermosetting resin layer during the thermal curing is 400°C or lower.

3. The method for manufacturing a laminate according to claim 1 or 2, wherein the thermal curing of the thermosetting resin layer is performed at a temperature 20°C or higher than the thermal curing start temperature of the thermosetting resin layer.

4. A laminate having, in this order, a first glass substrate, a resin layer, and a second glass substrate, wherein the average coefficient of thermal expansion of the second glass substrate is greater than that of the first glass substrate, and the difference in average coefficient of thermal expansion between the first glass substrate and the second glass substrate is 0.6 to 1.5 ppm / °C, and the laminate has warpage.

5. The laminate according to claim 4, wherein the outer surface of the first glass substrate is a surface on which an electronic device is formed.

6. The laminate according to claim 4, wherein the first glass substrate, the resin layer, and the second glass substrate are curved such that the outer surface of the first glass substrate is convex, and an electronic device is disposed on the curved first glass substrate.

7. The laminate according to any one of claims 4 to 6, wherein the total thickness of the laminate is 0.3 to 3.0 mm.

8. The laminate according to any one of claims 4 to 7, wherein the amount of warpage of the laminate is more than 0 μm and 500 μm or less.

9. The laminate according to any one of claims 4 to 8, wherein the amount of warpage of the laminate after heating at 250°C for 3 hours is more than 0 μm and 500 μm or less.

10. Preparing a laminate having, in this order, a first glass substrate, a resin layer, and a second glass substrate, and having warpage, wherein the average coefficient of thermal expansion of the second glass substrate is greater than that of the first glass substrate; Forming a rewiring layer on the outer surface of the first glass substrate; a step of electrically connecting the semiconductor device to the rewiring layer; a step of encapsulating the semiconductor device with a resin; A method of manufacturing a semiconductor package, comprising a step of peeling the rewiring layer on which the semiconductor device encapsulated with the resin is mounted from the first glass substrate.

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