Method for manufacturing multilayer substrate, and semiconductor device

Abstract

In one example of this method for manufacturing a package substrate, a first substrate 30 having a cured insulating layer, a second substrate 40 having a cured insulating layer, a third substrate 50 having a cured insulating layer, and a fourth substrate 60 having a cured insulating layer are prepared. A semi-cured bonding body 70 (prepreg) is sandwiched and laminated between the first substrate 30 and the second substrate 40, and then the same is cured to form a first laminated substrate 100. Similarly, a semi-cured bonding body 80 is sandwiched and laminated between the third substrate 50 and the fourth substrate 60, and then the same is cured to form a second laminated substrate 110. Thereafter, a semi-cured bonding body 90 is sandwiched and laminated between the first laminated substrate 100 and the second laminated substrate 110, and then the same is cured to form a package substrate 1. According to this method, the steps can be shortened as compared with the case where layers are laminated one by one in order, and the shortening effect is prominent especially when the number of layers to be laminated is large.

Description

Multilayer substrate manufacturing method and semiconductor device

[0001] The present disclosure relates to a method for manufacturing a multilayer substrate, and more particularly to a method for manufacturing a package substrate.

[0002] Non-Patent Document 1 discloses a method for laminating printed wiring boards in one go. In this method, a core substrate with copper foil on both sides is etched using a subtractive process, and the etched core substrate is then stacked with a prepreg interposed between them under heat and pressure to form a laminate. Through-holes are then drilled in the laminate, and the walls of the through-holes are copper-plated (through-hole plating) to ensure electrical continuity between the upper and lower layers. This method is used, for example, in the manufacture of motherboards. However, when a board is fabricated using this method, the through-holes penetrate all layers of the board, which limits the planar wiring within a single layer. To address this issue, a technology called microvias has been developed. In this technology, instead of drilling holes that penetrate all layers of the board, holes are drilled in each insulating layer to ensure electrical continuity only between the upper and lower layers (see Non-Patent Document 2). Another known build-up method involves attaching an insulating film, then opening vias using laser processing, and then repeatedly forming wiring using a semi-additive process (see Non-Patent Document 3). This method allows for the formation of multiple wiring patterns on a single layer.

[0003] Furthermore, as semiconductor products become more powerful, the number of input / output terminals required for package substrates is increasing. However, there are limitations on the number of wiring lines that can be formed on a single wiring line. Therefore, efforts are being made to increase the number of buildup layers in package substrates, and plans are being considered to increase the number of buildup layers from nine to twelve (Non-Patent Document 4). However, because the buildup method involves stacking insulating layers one by one, there is a problem in that the substrate fabrication time increases in proportion to the number of layers stacked. To solve this problem, multilayer substrates using the PALAP method have been developed (see, for example, Non-Patent Document 5 and Patent Documents 1 and 2). This method involves preparing multiple substrates in a thermoplastic resin with a copper pattern formed on one side, drilling holes on the opposite side of the copper pattern, and injecting conductive powder into the holes. The prepared substrates are then stacked together to produce a multilayer substrate.

[0004] JP 2004-146694 A JP 2011-187843 A

[0005] Toshiki Suzumebe, "History of Printed Wiring Boards," Journal of the Japan Institute of Electronics Packaging, Vol. 16, No. 6 (2013), pp. 428-432; Hirotaka Ueda, "Applications and Technical Issues of Conductive Adhesives in Mobile Phone Terminals," Journal of the Japan Institute of Electronics Packaging, Vol. 9, No. 3 (2006), pp. 211-218; Michio Horiuchi et al., "Metallization technologies on a smooth resin surface for the next generation of flip chip packaging," Transactions of the Japan Institute of Electronics Packaging, Vol. 3, No. 1 (2010), pp. 110-115; FC-BGA Substrate, Roadmap, [online], 2022, [Retrieved April 27, 2023], Internet <URL: https: / / www.toppan.co.jp / electronics / package / fc-bga / >; Yoshitaro Yazaki et al. "Development of PALAP Multilayer Substrates Using Solid-State Diffusion Bonding," Denso Technical Review, Vol. 10, No. 2 (2005), pp. 85-89

[0006] As mentioned above, in the build-up method, insulating layers are stacked one by one, so the time required to fabricate a substrate increases in proportion to the number of layers. On the other hand, in the case of a batch stacking method such as PALAP, misalignment between the wiring may occur. Therefore, there is a need to develop a method that can efficiently fabricate multilayer substrates while suppressing misalignment between the wiring.

[0007] An object of the present disclosure is to provide a method for manufacturing a multilayer substrate that can efficiently manufacture the multilayer substrate while suppressing misalignment of each wiring.

[0008] [1] One aspect of the present disclosure relates to a method for manufacturing a multilayer substrate, the method for manufacturing the multilayer substrate including the steps of: preparing a first substrate having a first insulating layer, a first wiring provided on a first surface of the first insulating layer, a second wiring provided on a second surface of the first insulating layer, and a first via penetrating the first insulating layer and connecting the first wiring and the second wiring to each other; preparing a second substrate having a second insulating layer, a third wiring provided on the first surface of the second insulating layer, a fourth wiring provided on the second surface of the second insulating layer, and a second via penetrating the second insulating layer and connecting the third wiring and the fourth wiring to each other; The method includes the steps of: preparing a third substrate having a third via that penetrates the third insulating layer and connects the fifth wiring and the sixth wiring to each other; preparing a first bonding body having a first bonding material and a first connecting via that penetrates the first bonding material; preparing a second bonding body having a second bonding material and a second connecting via that penetrates the second bonding material; stacking the first substrate and the second substrate so as to sandwich the first bonding body therebetween to produce a first laminated substrate; preparing a second laminated substrate including the third substrate; and stacking the first laminated substrate and the second laminated substrate so as to sandwich the second bonding body therebetween to produce a third laminated substrate.

[0009] In this method for manufacturing a multilayer substrate, a first laminated substrate is first fabricated by stacking a first substrate and a second substrate with a first bonded body sandwiched therebetween, and a second laminated substrate including a third substrate is prepared. Then, the first laminated substrate and the second laminated substrate are stacked with a second bonded body sandwiched therebetween to fabricate a third laminated substrate, which is a multilayer substrate. In this case, the number of layers can be increased by doubling, etc., thereby shortening the time required to fabricate a multilayer substrate compared to a method in which layers are stacked one by one. Meanwhile, because each laminated plate does not involve stacking multiple substrates at once, misalignment of the wiring is less likely to occur. Therefore, this method for manufacturing a multilayer substrate can efficiently fabricate a multilayer substrate while suppressing misalignment of the wiring.

[0010] [2] The method for manufacturing a multilayer substrate according to [1] above preferably further includes the steps of: preparing a fourth substrate having a fourth insulating layer, a seventh wiring provided on a first surface of the fourth insulating layer, an eighth wiring provided on a second surface of the fourth insulating layer, and a fourth via penetrating the fourth insulating layer and connecting the seventh wiring and the eighth wiring to each other; and preparing a third bonding body having a third bonding material and a third connecting via penetrating the third bonding material. In the step of preparing the second laminated substrate, the third substrate and the fourth substrate are preferably stacked so as to sandwich the third bonding body therebetween to produce the second laminated substrate. In this case, the time required to produce a multilayer substrate having at least eight layers of wiring can be further shortened.

[0011] [3] In the method for manufacturing a multilayer substrate according to [1] or [2] above, the first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer are preferably insulating layers containing a cured curable resin. In this case, the first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer are not melted by heating in subsequent lamination processes, etc., and misalignment of the wiring provided on each insulating layer is less likely to occur. Therefore, this method for manufacturing a multilayer substrate can more reliably suppress misalignment of each wiring. Note that the curable resin referred to here may be, for example, a thermosetting resin.

[0012] [4] In the method for manufacturing a multilayer substrate according to [1] or [2] above, the first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer may be glass substrates. In this case, the first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer will not melt due to heating in a subsequent lamination process, etc., and misalignment of the wiring provided on each insulating layer will be unlikely to occur. Therefore, this method for manufacturing a multilayer substrate can more reliably suppress misalignment of each wiring.

[0013] [5] In the method for manufacturing a multilayer substrate according to any one of [1] to [4] above, the first bonding material is preferably an insulating layer containing a semi-cured or uncured curable resin before the first laminate substrate is fabricated, and the second bonding material is preferably an insulating layer containing a semi-cured or uncured curable resin before the third laminate substrate is fabricated. In this case, bonding between the first substrate and the second substrate and bonding between the first laminate substrate and the second laminate substrate can be performed reliably and easily.

[0014] [6] In the method for manufacturing a multilayer substrate according to any one of [1] to [5] above, at least one of the first via, the second via, and the first connecting via may be provided at a position in a planar direction different from that of the other vias. In this case, the degree of freedom in designing the wiring pattern of each wiring can be improved.

[0015] [7] In the method for manufacturing a multilayer substrate according to any one of [1] to [6] above, the first connection via may be provided at a position in a planar direction different from the first via and the second via. In this case, the degree of freedom in designing the wiring pattern of each wiring can be improved.

[0016] [8] The method for manufacturing a multilayer substrate according to any one of [1] to [7] above may further include a step of preparing a fourth bonding body having a fourth bonding material and a fourth connection via penetrating the fourth bonding material. In the step of producing a third laminate substrate, two third laminate substrates may be produced by stacking the first laminate substrate and the second laminate substrate so as to sandwich the second bonding material therebetween. A fourth laminate substrate may then be produced by stacking two third laminate substrates so as to sandwich the fourth bonding material therebetween. In this case, a multilayer substrate having a larger number of wiring layers, such as 12 or 16 layers, can be efficiently produced.

[0017] [9] The method for manufacturing a multilayer substrate according to any one of [1] to [8] above may further include a step of forming external terminals on the outermost layer of the multilayer substrate. In this case, a multilayer substrate having external terminals can be manufactured.

[0018]

[10] In the method for manufacturing a multilayer substrate according to any one of the above [1] to [9], the multilayer substrate to be manufactured is preferably a package substrate.

[0019]

[11] The method for manufacturing a multilayer substrate according to any one of [1] to

[10] above may further include a step of inspecting at least one of the first, second, third, and fourth substrates before stacking them. In this case, defective substrates or substrates with a high defect rate are removed, and non-defective substrates or substrates with a high defect rate are advanced to the next step, thereby improving the overall yield rate of the multilayer substrate.

[0020]

[12] In the method for manufacturing a multilayer substrate according to any one of [1] to

[11] above, the step of preparing a first substrate may include preparing a plurality of first substrates, the step of preparing a second substrate may include preparing a plurality of second substrates, and the step of fabricating a first laminated substrate may include fabricating a plurality of first laminated substrates, each of the plurality of first substrates and each of the plurality of second substrates being a large-sized substrate including a plurality of wiring portions. The step of inspecting may include inspecting each wiring portion of each of the plurality of first substrates and inspecting each wiring portion of each of the plurality of second substrates. In the step of fabricating a first laminated substrate, it is preferable to select a combination of each of the plurality of first substrates and each of the plurality of second substrates based on the inspection results of the inspection step. This allows the overall yield rate of the multilayer substrate to be further improved by excluding defective substrates or substrates with a high defect rate and proceeding to the next step with non-defective substrates or substrates with a high defect rate.

[0021]

[13] In the method for manufacturing a multilayer substrate according to

[12] above, in the step of fabricating the first laminated substrate, selection may be performed so that wiring portions determined to be non-defective in the inspection step are superimposed on each other. In this case, the yield rate of the multilayer substrate can be further improved.

[0022] According to the present disclosure, it is possible to efficiently manufacture a multilayer substrate while suppressing misalignment of each wiring.

[0023] FIG. 1 is a cross-sectional view showing an example of a cross-sectional configuration of a package substrate (multilayer substrate) according to an embodiment of the present invention. FIGS. 2A and 2B are cross-sectional views showing a method for manufacturing the package substrate shown in FIG. 1. FIG. 3 is a cross-sectional view showing a method for manufacturing the package substrate shown in FIG. 1, illustrating a step performed after the step shown in FIG. 2. FIG. 4 shows another example of a step performed after the step shown in FIG. 2. FIG. 5 is a diagram for explaining a bonding step that reflects the results of an inspection step. FIG. 6 is a diagram for explaining a bonding step that reflects the results of an inspection step. FIG. 7 is a perspective view for explaining the bonding step of FIGS. 5 and 6. FIG. 8 is a diagram for explaining a bonding step that does not reflect the results of the inspection step when there are multiple substrates. FIG. 9 is a diagram for explaining a bonding step that reflects the results of the inspection step when there are multiple substrates, and then performs a selection process.

[0024] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent parts will be denoted by the same reference numerals, and duplicate explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0025] In this specification, the term "layer" includes not only a structure having a shape formed over the entire surface when observed in a plan view, but also a structure having a shape formed on a portion thereof. In this specification, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0026] In this specification, numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a numerical range in one stage may be replaced with the upper or lower limit of a numerical range in another stage. In numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0027] FIG. 1 is a diagram illustrating an example of a package substrate manufactured by a manufacturing method according to an embodiment of the present invention. As shown in FIG. 1 , the package substrate 1 (multilayer substrate, third laminated substrate) is a substrate having eight wiring layers. The package substrate 1 includes a first wiring layer 11, a second wiring layer 12, a third wiring layer 13, a fourth wiring layer 14, a fifth wiring layer 15, a sixth wiring layer 16, a seventh wiring layer 17, an eighth wiring layer 18, a first insulating layer 21, a second insulating layer 22, a third insulating layer 23, a fourth insulating layer 24, a fifth insulating layer 25, a sixth insulating layer 26, and a seventh insulating layer 27. Each of the wiring layers from the first wiring layer 11 to the eighth wiring layer 18 can be formed by, for example, a subtractive method or a semi-additive method. Other methods may also be used. The first wiring layer 11 to the eighth wiring layer 18 are formed from a metal such as copper. The thickness of the first wiring layer 11 to the eighth wiring layer 18 is, for example, 5 μm to 35 μm, and preferably 9 μm to 25 μm.

[0028] The first to seventh insulating layers 21 to 27 are formed of a curable resin such as a thermosetting resin, and are in the form of a cured resin in the package substrate 1. The first to seventh insulating layers 21 to 27 may contain glass cloth G in the curable resin, or may not contain glass cloth G. The first to seventh insulating layers 21 to 27 are, for example, a cured prepreg. The first to seventh insulating layers 21 to 27 may be formed from a glass substrate. The first to seventh insulating layers 21 to 27 are disposed between the first to eighth wiring layers 11 to 18, respectively, to ensure insulation between the wiring layers. Meanwhile, the first to seventh insulating layers 21 to 27 may be provided with vias (microvias) penetrating each insulating layer, and these vias are configured to ensure necessary electrical continuity between the wiring layers. Such a package substrate 1 may be, for example, a package substrate for an FC-BGA. Although the package substrate 1 shown in FIG. 1 has eight wiring layers (first wiring layer 11 to eighth wiring layer 18), it is not limited to this and may have six wiring layers, 12 wiring layers, 16 wiring layers, or 24 wiring layers.

[0029] Next, a method for manufacturing the package substrate 1 will be described with reference to Figures 2 and 3. Figures 2(a) and 2(b) are cross-sectional views showing the method for manufacturing the package substrate shown in Figure 1. Figure 3 is a cross-sectional view showing the method for manufacturing the package substrate shown in Figure 1, illustrating a step performed after the step shown in Figure 2. This manufacturing method includes the following steps [A] to [J].

[0030] Step A: Preparing a first substrate having a first insulating layer, a first wiring provided on a first surface of the first insulating layer, a second wiring provided on a second surface of the first insulating layer, and a first via that penetrates the first insulating layer and connects the first wiring and the second wiring to each other. Step B: Preparing a second substrate having a second insulating layer, a third wiring provided on a first surface of the second insulating layer, a fourth wiring provided on a second surface of the second insulating layer, and a second via that penetrates the second insulating layer and connects the third wiring and the fourth wiring to each other. Step C: Preparing a third substrate having a third insulating layer, a fifth wiring provided on a first surface of the third insulating layer, a sixth wiring provided on a second surface of the third insulating layer, and a third via that penetrates the third insulating layer and connects the fifth wiring and the sixth wiring to each other. Step D: A step of preparing a fourth substrate having a fourth insulating layer, a seventh wiring provided on a first surface of the fourth insulating layer, an eighth wiring provided on a second surface of the fourth insulating layer, and a fourth via that penetrates the fourth insulating layer and connects the seventh wiring and the eighth wiring to each other. Step E: A step of preparing a first bonding body having a first bonding material and a first connection via that penetrates the first bonding material. Step F: A step of preparing a third bonding body having a third bonding material and a third connection via that penetrates the third bonding material. Step G: A step of preparing a second bonding body having a second bonding material and a second connection via that penetrates the second bonding material. Step H: A step of stacking the first substrate and the second substrate so as to sandwich the first bonding body therebetween to produce a first laminated substrate. Step I: A step of stacking the third substrate and the fourth substrate so as to sandwich the third bonding body therebetween to produce a second laminated substrate. Step J: A step of stacking the first laminate substrate and the second laminate substrate so as to sandwich the second bonded body therebetween to produce a multilayer substrate.

[0031] 2A, a first substrate 30 is prepared. The first substrate 30 has an insulating layer 31 (first insulating layer), a wiring layer 32 (first wiring) provided on a first surface 31a of the insulating layer 31, a wiring layer 33 (second wiring) provided on a second surface 31b of the insulating layer 31, and a via 34 (first via) that penetrates the insulating layer 31 and connects the wiring layer 32 and the wiring layer 33 to each other.

[0032] The insulating layer 31 is composed of a thermosetting resin such as an epoxy resin, and is formed, for example, from a prepreg containing glass cloth G. The resin composition constituting the insulating layer 31 may contain a curing agent such as a phenolic resin compound, an acid anhydride compound, an amine compound, or a hydrazide compound. The insulating layer 31 is a cured product (so-called C stage) formed by curing the prepreg or the like. In a cured state, the insulating layer 31 has a thickness of, for example, 7 μm to 100 μm, and preferably 20 μm to 60 μm. The insulating layer 31 may also be a glass substrate.

[0033] A wiring layer 32 is formed on the first surface 31a of the insulating layer 31. A wiring layer 33 is formed on the second surface 31b of the insulating layer 31. The wiring layers 32, 33 are wirings made of metal such as copper, gold, or silver, and can be formed in the insulating layer 31 by a subtractive method or a semi-additive method. They may also be formed by other methods. The wiring layers 32, 33 may be metal plating layers, metal foils such as copper foils, layers formed by vapor deposition such as sputtering, or metal sintered layers. The thickness of the wiring layers 32, 33 may be, for example, 5 μm to 35 μm. The insulating layer 31 may further include vias 34 formed therein, penetrating the insulating layer 31 in the stacking direction and connecting the wiring layers 32 and 33 to each other. The vias 34 are made of metal such as copper.

[0034] [Step B] In step B, a second substrate 40 is prepared. The second substrate 40 has a configuration similar to that of the first substrate 30, and includes an insulating layer 41 (second insulating layer), a wiring layer 42 (third wiring) provided on a first surface 41 a of the insulating layer 41, a wiring layer 43 (fourth wiring) provided on a second surface 41 b of the insulating layer 41, and vias 44 (second vias) that penetrate the insulating layer 41 and connect the wiring layer 42 and the wiring layer 43 to each other. The materials and methods of forming the insulating layer 41 and the wiring layers 42 and 43 of the second substrate 40 are similar to those of the first substrate 30, and therefore detailed description thereof will be omitted.

[0035] [Step C] In step C, a third substrate 50 is prepared. The third substrate 50 has a configuration similar to that of the first substrate 30, and includes an insulating layer 51 (third insulating layer), a wiring layer 52 (fifth wiring) provided on a first surface 51 a of the insulating layer 51, a wiring layer 53 (sixth wiring) provided on a second surface 51 b of the insulating layer 51, and a via 54 (third via) that penetrates the insulating layer 51 and connects the wiring layer 52 and the wiring layer 53 to each other. The materials and methods of forming the insulating layer 51 and the wiring layers 52 and 53 of the third substrate 50 are similar to those of the first substrate 30, and therefore detailed description thereof will be omitted.

[0036] [Step D] In step D, a fourth substrate 60 is prepared. The fourth substrate 60 has a configuration similar to that of the first substrate 30, and includes an insulating layer 61 (fourth insulating layer), a wiring layer 62 (seventh wiring) provided on a first surface 61 a of the insulating layer 61, a wiring layer 63 (eighth wiring) provided on a second surface 61 b ​​of the insulating layer 61, and a via 64 (fourth via) that penetrates the insulating layer 61 and connects the wiring layer 62 and the wiring layer 63 to each other. The materials and methods of forming the insulating layer 61 and the wiring layers 62 and 63 of the fourth substrate 60 are similar to those of the first substrate 30, and therefore detailed description thereof will be omitted.

[0037] [Step E] In step E, a bonded body 70 (first bonded body) is prepared. The bonded body 70 includes a bonding material 71 (first bonding material) and connection vias 72 (first connection vias) that penetrate the bonding material 71. The bonding material 71 of the bonded body 70 is a member that bonds the first substrate 10 and the second substrate 20. For example, the bonding material 71 is a semi-cured (B-stage) or uncured curable resin such as a thermosetting resin, and is composed of a prepreg containing glass cloth G. The bonding material 71 is formed from a resin or the like and has insulating properties. The bonding material 71 is provided with connection vias 72 that penetrate the bonding material 71. The connection vias 72 are formed from a metal such as copper. The bonding material 71 is preferably composed of the same prepreg as the insulating layers 31, 41, 51, and 61. However, the bonding material 71 is different from the first bonded body 70 in that it is in a semi-cured or uncured state before bonding (before step H, described below).

[0038] [Step F] In step F, a bonded body 80 (third bonded body) is prepared. Like the bonded body 70, the bonded body 80 has a bonding material 81 (third bonding material) and a connection via 82 (third connection via) penetrating the bonding material 81. The materials and methods for forming the bonding material 81 (insulating layer) and the connection via 82 of the bonded body 80 are the same as those of the bonded body 70, and therefore detailed description thereof will be omitted.

[0039] [Step G] In step G, a bonded body 90 (second bonded body) is prepared (see FIG. 3 ). Like the bonded body 70, the bonded body 90 has a bonding material 91 (second bonding material) and connection vias 92 (second connection vias) that penetrate the bonding material 91. The materials and methods for forming the bonding material 91 (insulating layer) and connection vias 92 of the bonded body 90 are the same as those of the bonded body 70, and therefore detailed description thereof will be omitted.

[0040] [Step H] In step H, as shown in FIGS. 2A and 2B , once the preparation of the first substrate 30, the second substrate 40, and the bonded structure 70 is complete, the first substrate 30 and the second substrate 40 are laminated together so that the bonded structure 70 is sandwiched between them to produce a first laminated substrate 100. That is, the semi-cured or uncured bonded structure 70 is sandwiched between the first substrate 30 and the second substrate 40 and functions as an adhesive, bonding the first substrate 30 and the second substrate 40 to form a laminated structure. Thereafter, the laminated structure is heated and pressurized to cure the semi-cured or uncured bonded structure 70, thereby producing the first laminated substrate 100. The temperature for curing is, for example, 100° C. to 250° C., and the pressure for pressing is 0.2 to 10 MPa. Furthermore, since the insulating layers 31, 41 of the first substrate 30 and the second substrate 40 are cured products of curable resin or glass substrates, even if they are heated in process H, the wiring layers 32, 33, wiring layers 42, 43, and vias 34, 44 will not shift from their original positions.

[0041] [Step I] In step I, once the preparation of the third substrate 50, the fourth substrate 60, and the bonded structure 80 is complete, the third substrate 50 and the fourth substrate 60 are laminated together so that the bonded structure 80 is sandwiched between them to produce a second laminated substrate 110. That is, similar to the first laminated substrate 100, the bonded structure 80 in a semi-cured or uncured state is sandwiched between the third substrate 50 and the fourth substrate 60 and functions as an adhesive to bond the third substrate 50 and the fourth substrate 60 to form a laminated structure. Thereafter, the laminated structure is heated and pressurized to cure the semi-cured or uncured bonded structure 80, thereby producing the second laminated substrate 110. The temperature and pressure required for curing are the same as those required for producing the first laminated substrate 100. Furthermore, since the insulating layers 51, 61 of the third substrate 50 and the fourth substrate 60 are cured products of a curable resin or glass substrates, even if they are heated in step I, the wiring layers 52, 53, wiring layers 62, 63, and vias 54, 64 will not shift from their original positions.

[0042] [Step J] In step J, as shown in FIG. 3 , once the preparation of the first laminate substrate 100, the second laminate substrate 110, and the bonded body 90 is complete, the first laminate substrate 100 and the second laminate substrate 110 are laminated together so that the bonded body 90 is sandwiched between them, thereby producing the package substrate 1. That is, the semi-cured or uncured bonded body 90 is sandwiched between the first laminate substrate 100 and the second laminate substrate 110 and functions as an adhesive, bonding the first laminate substrate 100 and the second laminate substrate 110 to form a laminate. Thereafter, the laminate is heated and pressurized to cure the semi-cured or uncured bonded body 90, thereby producing the package substrate 1 (see FIG. 1 ). The temperature and pressure for curing are the same as those used to produce the first laminate substrate 100, etc. Furthermore, since each insulating layer of the first laminate substrate 100 and the second laminate substrate 110 is a cured product of a curable resin or a glass substrate, even if they are reheated in process J, the wiring layers 32, 33, wiring layers 42, 43, wiring layers 52, 53, wiring layers 62, 63, and vias 34, 44, 54, 64 will not shift from their original positions.

[0043] In this way, eight wiring layers are formed by bonding laminated substrates each having four wiring layers. However, as shown in Fig. 4, a laminate may be formed by sandwiching a semi-cured or uncured bonded body 90 between a first laminated substrate 100, which is a laminated substrate having four wiring layers, and a third substrate 50, which has two wiring layers, to function as an adhesive, and bonding the first laminated substrate 100 and a second laminated substrate 110A including the third substrate 50. In this case, the laminate is then heated and pressurized to harden the semi-cured or uncured bonded body 90, thereby producing a six-layer package substrate.

[0044] External terminals may be formed on the outermost layer of the package substrate 1, which is a multilayer substrate obtained after laminating and curing the first laminate substrate 100 and the second laminate substrate 110. This produces a package substrate having external terminals. Furthermore, a semiconductor element can be mounted on the package substrate produced in this manner to produce a semiconductor device.

[0045] As described above, in the method for manufacturing a package substrate according to this embodiment, the first laminated substrate 100 is fabricated by stacking the first substrate 30 and the second substrate 40 so as to sandwich the bonded structure 70 therebetween. The third substrate 50 and the fourth substrate 60 are then stacked so as to sandwich the bonded structure 80 therebetween, or the second laminated substrate 110, 110A is fabricated so as to include the third substrate 50. The package substrate 1 is then fabricated by stacking the first laminated substrate 100 and the second laminated substrate 110, 110A so as to sandwich the bonded structure 90 therebetween. In this case, the number of layers can be multiplied, thereby shortening the time required to fabricate the package substrate 1 compared to a method in which layers are stacked one by one. Meanwhile, because each laminated board is not formed by stacking multiple substrates, misalignment of the wiring layers is less likely to occur. Therefore, this method for manufacturing a package substrate can efficiently fabricate a multilayer package substrate while suppressing misalignment of the wiring layers.

[0046] Furthermore, in the method for manufacturing a package substrate according to this embodiment, the insulating layers 31, 41, 51, and 61 are preferably insulating layers containing a cured thermosetting resin. In this case, the insulating layers are not melted by heating in the subsequent lamination process, and misalignment of the wiring layers is unlikely to occur. Therefore, this method for manufacturing a package substrate can more reliably suppress misalignment of the wiring layers.

[0047] Furthermore, in the method for manufacturing a package substrate according to this embodiment, the insulating layers 31, 41, 51, and 61 may be glass substrates. In this case, the insulating layers will not melt when heated in subsequent lamination processes, and misalignment of the wiring layers is unlikely to occur. Therefore, this method for manufacturing a package substrate can more reliably suppress misalignment of the wiring layers.

[0048] Furthermore, in the method for manufacturing a package substrate according to this embodiment, the bonded body 70 is preferably an insulating layer containing a semi-cured or uncured thermosetting resin before the first laminated substrate 100 is fabricated. The bonded body 80 is preferably an insulating layer containing a semi-cured or uncured thermosetting resin before the second laminated substrate 110 is fabricated. In this case, bonding between the first substrate 30 and the second substrate 40 and bonding between the third substrate 50 and the fourth substrate 60 can be performed reliably and easily. Furthermore, the bonded body 90 is preferably an insulating layer containing a semi-cured or uncured thermosetting resin before the package substrate 1 is fabricated. In this case, bonding between the first laminated substrate 100 and the second laminated substrate 110 can be performed reliably and easily.

[0049] Furthermore, in the method for manufacturing a package substrate according to this embodiment, the connection vias 72 and 82 may be provided at positions in a planar direction different from the vias 34 and 54 and the vias 44 and 64. In this case, the degree of freedom in designing the wiring pattern in each wiring layer can be improved.

[0050] 3 , two package substrates 1 formed by bonding and curing a first laminate substrate 100 and a second laminate substrate 110 with a bonded body 90 may be fabricated as third laminate substrates, and another bonded body (fourth bonded body) having a similar configuration to the bonded body 90 may be sandwiched between the two package substrates 1 (third laminate substrates) and laminated and cured to fabricate a package substrate (fourth laminate substrate) having 16 wiring layers. Like the bonded body 90, this other bonded body has a bonding material (fourth bonding material) and connection vias (fourth connection vias) that penetrate the bonding material. Fabrication in this manner allows efficient fabrication of package substrates with a greater number of layers, such as 16 layers.

[0051] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above-described embodiments and may be modified as appropriate without departing from the spirit of the present disclosure. For example, in the above-described package substrate manufacturing method, each substrate is laminated and then bonded together as a unit. Therefore, in the package substrate manufacturing method according to the present embodiment, a continuity test may be performed on the wiring portions 30a-30f, 40a-40f included in each substrate, as shown in FIGS. 5 and 6, before fabricating the laminate (e.g., before laminating the first substrate 30 and the second substrate 40 as shown in FIG. 7). In this case, each substrate is a large-sized substrate including multiple wiring portions, and the continuity test is performed by testing the continuity and insulation of each wiring portion from both sides of the substrate using a flying probe or the like. If the continuity test results in a wiring portion being determined to be defective (Fail) (see FIG. 6), the overall yield rate can be improved by not manufacturing that portion or not using that substrate. Fig. 5 shows a case where all wiring portions are good (OK), while Fig. 6 shows a case where some wiring portions are defective (Fail). In the example of Fig. 6, for example, wiring portions 30c, 40c and wiring portions 30e, 40e where good (OK) portions overlap are used as subsequent products, and since it is clear that the other wiring portions are defective (Fail), subsequent inspections can be omitted.

[0052] Furthermore, when a plurality of first substrates 30A, 30B, and 30C are fabricated and a plurality of second substrates 40A, 40B, and 40C are fabricated, each wiring portion of each of the plurality of first substrates 30A to 30C may be inspected (determined as OK or Fail) and each wiring portion of each of the plurality of second substrates 40A to 40C may be inspected (determined as OK or Fail), as shown in Fig. 8. Then, corresponding first substrates 30A and 40A, corresponding first substrates 30B and 40B, and corresponding first substrates 30C and 40C may be bonded together with respective bonding bodies 70, as shown in Fig. 8. In this case, for example, the number of overlapping non-defective wiring portions is seven. Alternatively, a selection process may be performed based on the inspection results of each wiring portion of the plurality of first substrates 30A-30C and the inspection results of each wiring portion of the plurality of second substrates 40A-40C, such that as many wiring portions determined to be good as possible are overlapped, and the first substrate and the second substrate may be bonded together, as shown in FIG. 9. In this case, for example, as shown in FIG. 9, the number of overlapping good wiring portions (overlapping OK portions) is 11. This selection process may be performed by using a computer to calculate the yield rate (yield) when all substrates are combined, or other processing methods may be used.

[0053] Although the above-described inspection process and non-defective product selection process have been described using the example of bonding the first substrate 30 and the second substrate 40 together, the present invention is not limited to this example and may also be applied to bonding the third substrate 50 and the fourth substrate 60 together, or bonding the first laminate substrate 100 and the second laminate substrate 110, 110A together. By performing such inspection and selection processes, it is possible to reliably improve the yield rate compared to when insulating layers are laminated all at once.

[0054] Furthermore, in the above-described embodiment, the case of manufacturing a package substrate has been described as an example, but it goes without saying that the present invention may also be applied to the case of manufacturing other multilayer substrates.

[0055] 1...package substrate (multilayer substrate, third laminated substrate), 30, 30A to 30C...first substrate, 31...insulating layer (first insulating layer), 32...wiring layer (first wiring), 33...wiring layer (second wiring), 34...via (first via), 40, 40A to 40C...second substrate, 41...insulating layer (second insulating layer), 42...wiring layer (third wiring), 43...wiring layer (fourth wiring), 44...via (second via), 50...third substrate, 51...insulating layer (third insulating layer), 52...wiring layer (fifth wiring), 53...wiring layer (sixth wiring), 54...via (third via), 60...fourth substrate, 61...insulating layer (fourth insulating layer), 62...wiring layer (seventh wiring), 63...wiring layer (eighth wiring), 64...via (fourth via), 70...bonded body (first bonding body), 71...bonding material (first bonding material), 72...connecting via (first connecting via), 80...bonded body (third bonding body), 81...bonding material (third bonding material), 82...connecting via (third connecting via), 90...bonded body (second bonding body), 91...bonding material (second bonding material), 92...connecting via (second connecting via), 100...first laminated substrate, 110, 110A...second laminated substrate.

Claims

1. A step of preparing a first substrate having a first insulating layer, a first wiring provided on the first surface of the first insulating layer, a second wiring provided on the second surface of the first insulating layer, and a first via that penetrates the first insulating layer and connects the first wiring and the second wiring to each other, A step of preparing a second substrate having a second insulating layer, a third wiring provided on the first surface of the second insulating layer, a fourth wiring provided on the second surface of the second insulating layer, and a second via that penetrates the second insulating layer and connects the third wiring and the fourth wiring to each other, A step of preparing a third substrate having a third insulating layer, a fifth wiring provided on the first surface of the third insulating layer, a sixth wiring provided on the second surface of the third insulating layer, and a third via that penetrates the third insulating layer and connects the fifth wiring and the sixth wiring to each other, A step of preparing a first joint having a first joining material and a first connecting via penetrating the first joining material, A step of preparing a second joint having a second joining member and a second connecting via penetrating the second joining member, A step of manufacturing a first laminated substrate by stacking the first substrate and the second substrate so that the first bond is sandwiched between them, A step of preparing a second laminated substrate including the third substrate, A step of manufacturing a third laminated substrate by stacking the first laminated substrate and the second laminated substrate so that the second bond is sandwiched between them, A method for manufacturing a multilayer substrate.

2. A step of preparing a fourth substrate having a fourth insulating layer, a seventh wiring provided on the first surface of the fourth insulating layer, an eighth wiring provided on the second surface of the fourth insulating layer, and a fourth via that penetrates the fourth insulating layer and connects the seventh wiring and the eighth wiring to each other, The process includes a step of preparing a third joint having a third joining member and a third connecting via penetrating the third joining member, In the step of preparing the second laminated substrate, the third substrate and the fourth substrate are stacked so that the third bond is sandwiched between them to produce the second laminated substrate. A method for manufacturing a multilayer substrate according to claim 1.

3. The first insulating layer, the second insulating layer, and the third insulating layer are insulating layers containing a cured curable resin. A method for manufacturing a multilayer substrate according to claim 1 or 2.

4. The first insulating layer, the second insulating layer, and the third insulating layer are glass substrates. A method for manufacturing a multilayer substrate according to claim 1 or 2.

5. The first bonding material is an insulating layer containing a semi-cured or uncured curable resin before the first laminated substrate is manufactured. The second bonding material is an insulating layer containing a semi-cured or uncured curable resin before the third laminated substrate is manufactured. A method for manufacturing a multilayer substrate according to claim 1 or 2.

6. At least one of the first via, the second via, and the first connecting via is located in a different planar position from the other vias. A method for manufacturing a multilayer substrate according to claim 1 or 2.

7. The first connecting via is located in a different planar direction from the first via and the second via. A method for manufacturing a multilayer substrate according to claim 1 or 2.

8. The process further comprises the step of preparing a fourth joint having a fourth joining member and a fourth connecting via penetrating the fourth joining member, In the process of manufacturing the third laminated substrate, two third laminated substrates are manufactured by stacking the first laminated substrate and the second laminated substrate with the second bonding material sandwiched between them. A fourth laminated substrate is fabricated by stacking two third laminated substrates with the fourth bonding material sandwiched between them. A method for manufacturing a multilayer substrate according to claim 1 or 2.

9. The process further includes forming external terminals on the outermost layer of the multilayer substrate. A method for manufacturing a multilayer substrate according to claim 1 or 2.

10. The aforementioned multilayer substrate is a package substrate. A method for manufacturing a multilayer substrate according to claim 1 or 2.

11. The process further includes inspecting at least one of the first substrate, the second substrate, and the third substrate before stacking them. A method for manufacturing a multilayer substrate according to claim 1 or 2.

12. In the process of preparing the first substrate, a plurality of first substrates are prepared. In the process of preparing the second substrate, a plurality of second substrates are prepared. In the process of manufacturing the first laminated substrate, a plurality of first laminated substrates are manufactured. Each of the plurality of first substrates and each of the plurality of second substrates is a large-format substrate including a plurality of wiring sections. In the inspection process, each wiring section on each of the plurality of first substrates is inspected, and each wiring section on each of the plurality of second substrates is inspected. In the process of manufacturing the first laminated substrate, a combination of each of the plurality of first substrates and each of the plurality of second substrates is selected based on the inspection results in the inspection process. A method for manufacturing a multilayer substrate according to claim 11.

13. In the process of manufacturing the first laminated substrate, selection is made so that the wiring sections that were judged to be good in the inspection process are superimposed on each other. A method for manufacturing a multilayer substrate according to claim 12.

14. A package substrate manufactured by the method for manufacturing a multilayer substrate according to claim 1 or 2, Semiconductor elements mounted on the aforementioned package substrate, A semiconductor device equipped with a semiconductor device.