Multilayer wiring board and method of manufacturing the same

Abstract

To solve the problem in which: when a multilayer wiring board is formed using a thin glass core board 1, multilayer wiring may be formed by attaching it to a carrier board 3 across a release layer 2 in order to prevent, e.g., damage to the glass core board in a manufacturing process; but, if an adherend by sputtering or plating during the multilayer wiring formation adheres to side faces of the release layer 2 and the carrier board 3, the carrier board cannot be peeled off in a stable manner.SOLUTION: To this end, a multilayer wiring board of the present invention has a glass core board above a carrier board across a release layer such that side faces of the carrier board is recessed in the center direction compared to side faces of the glass core board.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a multilayer wiring board and a method for manufacturing the multilayer wiring board. [Background technology]

[0002] In recent years, as electronic devices have become more sophisticated and smaller, there has been a demand for higher density semiconductor modules to be installed in these devices. To address this demand, improvements to the manufacturing processes for forming multilayer wiring and fine wiring have been investigated. In particular, recent multilayer wiring boards often employ a glass core substrate, with a structure in which a conductor layer, an insulating resin layer, and another conductor layer are laminated in this order on both sides of the substrate. However, when the glass core substrate is made of glass with a thickness of about 100 μm, cracks tend to occur during the manufacturing process.

[0003] For this reason, in Patent Document 1, a carrier substrate is used as a support to prevent cracking of a thin glass core substrate with through holes in a manufacturing process, and a resin layer with "mold-releasing properties" is used to bond the glass core substrate and the carrier substrate. Specifically, an acrylic resin that exhibits releasability upon exposure to ultraviolet light has been proposed as the resin layer.

[0004] By employing such a laminate structure, the risk of cracks or defects occurring in the thin glass core substrate with through holes during the manufacturing process is reduced. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6176253 Summary of the Invention [Problem to be solved by the invention]

[0006] However, while Patent Document 1 examines the adhesion and releasability at the interface between the glass core substrate and the resin layer, it does not examine the peelability at the side of the laminate between the glass core substrate and the resin layer, or the carrier substrate. In particular, the relationship between the process of forming the multilayer wiring board and the state of the side surface of the laminate or peelability has not been considered at all, which may cause problems when peeling the carrier substrate from the glass core substrate on which the multilayer wiring layer has been formed. Therefore, an object of the present invention is to provide a technique for stably peeling a carrier substrate from a glass core substrate. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, one representative multilayer wiring board of the present invention is a multilayer wiring board in which a glass core substrate is provided above a carrier substrate via a release layer, and an insulating resin sheet is placed above the glass core substrate, When the distance that the side of the glass core substrate is set back toward the center compared to the side of the insulating resin sheet is B, the distance that the side of the carrier substrate is set back toward the center compared to the side of the glass core substrate is G, and the thickness of the glass core substrate is Tg, B, G, and Tg satisfy the following formula (1). B-(Tg+G)<0 (1) [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a technique for stably carrying out the process of peeling and removing the carrier substrate from the glass core substrate. Problems, configurations, and effects other than those described above will become apparent from the following description of the preferred embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a conventional multilayer wiring board. [Figure 2]FIG. 2 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a conventional multilayer wiring board. [Figure 3] FIG. 3 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a conventional multilayer wiring board. [Figure 4] FIG. 4 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a conventional multilayer wiring board. [Figure 5] FIG. 5 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a conventional multilayer wiring board. [Figure 6] FIG. 6 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a conventional multilayer wiring board. [Figure 7] FIG. 7 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a conventional multilayer wiring board. [Figure 8] FIG. 8 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a multilayer wiring board of the present invention. [Figure 9] FIG. 9 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a multilayer wiring board of the present invention. [Figure 10] FIG. 10 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a multilayer wiring board of the present invention. [Figure 11] FIG. 11 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a multilayer wiring board of the present invention. [Figure 12] FIG. 12 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a multilayer wiring board of the present invention. [Figure 13] FIG. 13 is a diagram illustrating a manufacturing process for peeling off a carrier substrate using a multilayer wiring board of the present invention. [Figure 14] FIG. 14 is a cross-sectional view of a multilayer wiring board for explaining the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, in the description of the drawings, the same parts are designated by the same reference numerals. In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0011] In this disclosure, the term "surface" may refer not only to the surface of a plate-shaped member, but also to the interface of a layer contained in the plate-shaped member that is approximately parallel to the surface of the plate-shaped member. Furthermore, the terms "upper surface" and "lower surface" refer to the surface shown at the top or bottom of a drawing of a plate-shaped member or a layer contained in the plate-shaped member. The "upper surface" and "lower surface" may also be referred to as the "first surface" and "second surface."

[0012] Furthermore, the term "side surface" refers to a surface or thickness portion of a layer included in a plate-like member or a layer included in a plate-like member. Furthermore, a portion of a surface and a side surface may be collectively referred to as an "edge portion." Furthermore, "upward" refers to the direction vertically upward when the plate-like member or layer is placed horizontally. Furthermore, "upward" and its opposite, "downward," are sometimes referred to as the "positive Z-axis direction" and the "negative Z-axis direction," and the horizontal direction is sometimes referred to as the "X-axis direction" and the "Y-axis direction."

[0013] Furthermore, "planar shape" and "plan view" refer to the shape of a surface or layer when viewed from above. Furthermore, "cross-sectional shape" and "cross-sectional view" refer to the shape of a plate-like member or layer when cut in a specific direction and viewed from the horizontal direction. Furthermore, "center" means the center of a surface or layer, not the periphery, and "toward the center" means the direction from the periphery of the surface or layer toward the center of the planar shape of the surface or layer.

[0014] <Conventional example> First, problems with the conventional example will be described with reference to FIGS. FIG. 1 is a diagram illustrating the attachment of a carrier substrate according to a conventional example. In this disclosure, the term "carrier method" refers to a method for manufacturing a multilayer wiring substrate, which includes the steps of attaching a glass core substrate to a carrier substrate, which serves as a support, forming through holes and multilayer wiring in the glass core substrate, and then peeling off the carrier substrate.

[0015] (Glass core substrate 1) FIG. 1 is a cross-sectional view of a glass core substrate 1 above a carrier substrate 3, in which a through hole 5 is formed. In Fig. 1, glass core substrate 1 is made of alkali-free glass with a thickness of about 100 µm, and has through holes 5. Glass core substrate 1 is also bonded via release layer 2 to carrier substrate 3, which serves as a support. Then, before proceeding to the next step, contaminants on the surface of the glass core substrate 1 are removed by ultrasonic cleaning or the like. In the drawings of the present disclosure, only one through hole 5 is shown in the glass core substrate 1, but this is for the sake of convenience in order to clearly show the structure of the multilayer wiring board, and does not indicate that there is only one through hole formed in the glass core substrate 1 that is the subject of the present invention. Normally, multiple interposers are formed in one glass core substrate, and therefore many through holes are formed therein.

[0016] (Seed layer formation) Next, the step of forming the seed layer 4 will be described with reference to FIG. Figure 2 is a cross-sectional view in which a metal film (in the range of 10 nm or more and 1000 nm or less) that will become the seed layer 4 is formed by a sputtering method or the like on the first surface (the surface opposite to the surface bonded to the carrier substrate 3), which is the upper surface of the glass core substrate 1. The material of the metal film is, for example, Ti, Cu, electroless Ni, etc., and at least one metal layer selected from these is formed on the side surface of the through hole.

[0017] Next, a pattern of photoresist 6 is formed on the upper surface of the metal film that will become the seed layer 4. For example, using dry photoresist (RD1225) manufactured by Showa Denko Materials Inc., a laminating press process is performed on the first surface side, and the desired pattern is drawn, followed by development, thereby exposing the seed layer in the desired pattern.

[0018] (Formation of first wiring) Next, the formation of the first wiring 8 will be described with reference to Fig. 4. Power is supplied to the seed layer 4, and electrolytic copper plating is performed to a thickness of 2 µm or more and 15 µm or less. After plating, the dry film resist that is no longer needed is dissolved and peeled off, and the seed layer 4 is removed by etching, thereby forming the first wiring 8.

[0019] (Formation of interlayer insulating layer) Next, the formation of the interlayer insulating layer will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view showing a state in which, following Fig. 4, the seed layer 4 is removed by etching, and then a sheet of insulating resin 7 that becomes the interlayer insulating layer is formed on the upper surfaces of the glass core substrate and the first wiring. The interlayer insulating layer can be made of a sheet-like insulating resin that can be formed by vacuum lamination, vacuum pressing, roll lamination, or the like. In particular, to keep dielectric loss low, it is preferable to use a laminated film sheet with an increased content of inorganic material such as SiO2. Furthermore, when the content of inorganic material is high, the resin has low fluidity even when melted, so in this respect, a laminated film sheet with an increased content of inorganic material is also preferable. Specifically, it is preferable to laminate an insulating resin (ABF-GXT31, 32.5 μm thick) manufactured by Ajinomoto Fine-Techno Co., Inc., and process the insulating resin 7 so that the first wiring 8 is completely embedded in the insulating resin 7. In this case, the lamination process is performed using a vacuum press laminating device, and heating is performed at 100°C and a pressure of 20 kgf / cm. 2 First pressing, heating at 100℃ and 12kgf / cm 2 It is recommended to do a second pressing.

[0020] In order to form an interlayer insulating layer without any gaps on the upper surface of the glass core substrate 1, the sheet of insulating resin 7, which is the material for the interlayer insulating layer, is placed over an area larger than the glass core substrate 1, as shown in Fig. 5. As a result, the insulating resin 7 is placed so that it protrudes outward from the side surfaces of the glass core substrate 1. When the insulating resin 7 is subjected to a laminating press process, the insulating resin 7 that protrudes outward from the side surfaces of the glass core substrate 1 is adhered to the side surfaces of the glass core substrate 1, the side surfaces of the release layer 2, and even the side surfaces of the carrier substrate 3, as shown in Fig. 6.

[0021] In the next step, as shown in FIG. 7, a second carrier substrate 10 is formed on the upper surface of the insulating resin 7 via a second release layer 9. The reason for adhering the second carrier substrate is to make it easier to handle the glass core substrate 1 after the carrier substrate 3 is peeled off.

[0022] The next step is to peel the carrier substrate 3 from the glass core substrate 1 using the peel layer 2. The step of peeling off the carrier substrate 3 can be carried out by a method of reducing the adhesive strength of the adhesive layer of the release layer 2 by irradiating it with a laser or by heating it, or by a method of applying a physical force. However, as shown in FIG. 7, in the conventional example, insulating resin 7 adheres to the side surface of the wiring board, and carrier substrate 3 may not be peeled off reliably.

[0023] First Embodiment Next, a first embodiment of the present invention will be described with reference to FIGS. The first embodiment differs from the conventional example in that the area of ​​the glass core substrate 1 is larger than the area of ​​the carrier substrate 3 with adhesive. 8 to 13 are cross-sectional views showing the steps of manufacturing a multilayer wiring board in which the area of ​​the glass core substrate 1 is larger than the area of ​​the adhesive carrier substrate 3. In the following description, components that are the same as or equivalent to those in the above-mentioned conventional example are given the same reference numerals, and their description will be simplified or omitted.

[0024] 12 is laminated (temporarily attached) on the upper surfaces of the glass core substrate 1 and the first wiring, the carrier substrate 3 has a smaller area than the glass core substrate. In other words, as for the side surfaces of the glass core substrate 1 and the carrier substrate 3, if the side surface of the carrier substrate 3 is sufficiently recessed toward the center compared to the side surface of the glass core substrate 1, the insulating resin 7 can be formed without adhering to the side surfaces of the carrier substrate 3 and the release layer 2 even after the insulating resin 7 is vacuum press laminated. As a result, in the peeling process of the multilayer wiring board shown in Figure 13, since the insulating resin 7 is not adhered to the sides of the carrier substrate or the release layer, the process of peeling and removing the carrier substrate 3 from the glass core substrate can be carried out stably.

[0025] <Second embodiment> Next, a second embodiment will be described with reference to FIG. The second embodiment differs from the first embodiment in that the distance that the side surface of the carrier substrate 3 is set back toward the center compared to the side surface of the glass core substrate 1 is defined in relation to the distance that the insulating resin 7 sheet protrudes beyond the side surface of the glass core substrate 1 and the thickness of the glass core substrate. In the following description, components that are the same as or equivalent to those in the above-mentioned conventional example are given the same reference numerals, and their description will be simplified or omitted. 14, in the second embodiment, the distance by which the side surface of the carrier substrate 3 is set back toward the center compared to the side surface of the glass core substrate 1 is defined as G. In this case, the distance by which the sheet of insulating resin 7 protrudes outward beyond the side surface of the glass core substrate 1 is defined as B, and the thickness of the glass core substrate 1 is defined as Tg. Note that G refers to the shortest distance that the side surface of the carrier substrate recedes toward the center compared to the side surface of the glass core substrate, and B refers to the shortest distance that the insulating resin 7 sheet protrudes outward beyond the side surface of the glass core substrate 1. In the second embodiment, the relationship between G, B and Tg satisfies the following formula (1). B-(Tg+G)<0 (1) If the above formula (1) is satisfied, the insulating resin 7 does not wrap around during the laminating press process and adheres to the side surfaces of the carrier substrate and the release layer, and a multilayer wiring board can be formed.

[0026] <Third embodiment> Next, a third embodiment will be described. The third embodiment differs from the second embodiment in that the distance B by which the insulating resin 7 sheet protrudes outward from the side surface of the glass core substrate 1 is defined by the relationship between the area of ​​the insulating resin 7 sheet and the area ratio of the glass core substrate 1. In other words, when the sheet of insulating resin 7 and the glass core substrate are made to have approximately similar shapes and are stacked with the center points of their respective faces overlapping, the area of ​​the sheet of insulating resin 7 can be set larger than the area of ​​the glass core substrate 1, thereby controlling the distance by which the side of the glass core substrate recedes toward the center compared to the side of the sheet of insulating resin 7. In the third embodiment, the area of ​​the glass core substrate 1 is set to 99% or less of the area of ​​the insulating resin sheet . In this way, by setting the area ratio when the center points of the insulating resin 7 sheet and the glass core substrate 1 are overlapped and laminated, the insulating resin 7 can be formed without adhering to the sides of the carrier substrate or release layer due to its wraparound after the laminating press process.

[0027] <Fourth embodiment> Next, a fourth embodiment will be described. The fourth embodiment differs from the third embodiment in that the distance G by which the side surface of the carrier substrate 3 is set back toward the center from the side surface of the glass core substrate 1 is set to 0.7 mm or more, and the distance B by which the sheet of insulating resin 7 protrudes outward beyond the side surface of the glass core substrate 1 is set to 10 mm or less. By defining the distance G between the side of the carrier substrate and the side of the glass core substrate and the distance B by which the sheet of insulating resin 7 extends beyond the side of the glass core substrate 1 as absolute values, the insulating resin 7 can be formed without adhering to the side of the carrier substrate or the release layer by wrapping around during press lamination processing.

[0028] <Example> Examples according to embodiments of the present invention and comparative examples will be described below with reference to Table 1. [Table 1] The examples and comparative examples shown in Table 1 were obtained by varying the distance that the side of the carrier substrate 3 was set back toward the center compared to the side of the glass core substrate 1 and the distance that the sheet of insulating resin 7 protruded outside the side of the glass core substrate 1, and then applying the insulating resin 7 by a laminating press process, and then evaluating the stability of peeling in each case. The assumed composition of the insulating resin 7 sheet and the processing conditions for laminating press are as follows. (Conditions for forming insulating resin sheets) Equipment: Vacuum laminator CVP-60 (manufactured by Nikko Materials Co., Ltd.) 1st press vacuum time 120sec Press pressure 20kgf / cm 2 Press time 120 seconds Temperature 100℃ 2nd press without vacuum Press pressure 12kgf / cm 2 Press time 120 seconds Temperature 100℃

[0029] As is clear from Table 1 above, when formula (1) is satisfied in the second embodiment, or when the area of ​​the glass core substrate 1 in the third embodiment is 99% or less of the area of ​​the insulating resin 7 sheet and the area ratio is 1% or more, it can be seen that good results can be obtained in terms of peel stability. Furthermore, in the fourth embodiment, the distance G by which the side of the carrier substrate is set back toward the center compared to the side of the glass core substrate is set to 0.72 mm or more, and the distance B by which the sheet of insulating resin 7 protrudes outside the side of the glass core substrate 1 is set to 10 mm or less, so that it is possible to obtain good results in terms of peel stability.

[0030] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention. For example, the first to fourth embodiments have been described on the premise that there is a problem of peeling of the carrier substrate 3 due to the insulating resin 7 provided above the glass core substrate 1 wrapping around the insulating resin 7 . However, the present invention is not limited to this, and can also be applied to a case where a second carrier substrate 10 is placed above the glass core substrate 1 and a second insulating resin is formed below the glass core substrate 1. If the present invention is applied to the second insulating resin and the second carrier substrate, it is also possible to stably peel off the second carrier substrate. [Explanation of symbols]

[0031] 1: Glass core substrate 2: Peel layer 3: Carrier board 4: Seed layer 5:Through hole 6: Photoresist 7: Insulating resin 8: 1st wiring 9: Second release layer 10: Second carrier board

Claims

1. A multilayer wiring board in which a glass core substrate is provided above a carrier substrate via a release layer, and an insulating resin sheet is provided above the glass core substrate, When the distance that the side surface of the carrier substrate is set back toward the center compared to the side surface of the glass core substrate is G, the distance that the insulating resin sheet protrudes outward from the side surface of the glass core substrate is B, and the thickness of the glass core substrate is Tg, G, B, and Tg satisfy the following formula (1): A multilayer wiring board characterized by: B-(Tg+G)<0...(1)

2. 2. The multilayer wiring board according to claim 1, The insulating resin sheet and the glass core substrate are substantially similar in shape and are laminated with the center points of their surfaces overlapping, and the area of ​​the glass core substrate is 99% or less of the area of ​​the insulating resin sheet. A multilayer wiring board characterized by:

3. 2. The multilayer wiring board according to claim 1, The distance by which the side surface of the carrier substrate is recessed toward the center compared to the side surface of the glass core substrate is 0.7 mm or more, and the distance by which the insulating resin sheet protrudes outward beyond the side surface of the glass core substrate is 10 mm or less. A multilayer wiring board characterized by:

4. A method for manufacturing a multilayer wiring substrate, comprising: providing a glass core substrate above a carrier substrate via a release layer; providing an insulating resin sheet above the glass core substrate; providing a second release layer and a second carrier substrate above the insulating resin sheet; and then peeling off the carrier substrate; a first step of forming the carrier substrate, the glass core substrate, and the insulating resin sheet so that G, B, and Tg satisfy the following formula (1), where G is a distance that the side surface of the carrier substrate is recessed toward the center compared to the side surface of the glass core substrate, B is a distance that the insulating resin sheet protrudes outward from the side surface of the glass core substrate, and Tg is a thickness of the glass core substrate; B-(Tg+G)<0...(1) a second step of performing a laminating press process on the insulating resin sheet to fix the insulating resin after the first step; a third step of peeling the carrier substrate from the glass core substrate after the second step; A method for manufacturing a multilayer wiring board having the above structure.

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