WO2005029933A1 - Multilayer printed wiring board and method for manufacturing same - Google Patents

Abstract

A multilayer printed wiring board formed by mass lamination, wherein wiring patterns (3, 4) and positioning patterns (3a, 3b, and so on) are formed on the back and front surfaces of a base (2) of a two-layer core sheet (1); copper foils (7, 8) are provided on both sides of on the core sheet via prepregs (5, 6); location holes (9, 10) are formed in portions of the copper foils or the prepregs, referring to the positioning patterns detected by X rays; and wiring patterns (11, 12) are formed by etching the copper foils while using the location holes for alignment of the wiring layers. Consequently, high-density, small-sized, low-cost multilayer printed wiring board is utilized for advanced portable devices.

Description

 Description Multilayer printed wiring board and method of manufacturing the same

 The present invention relates to a printed wiring board and a method of manufacturing the same, and more particularly, to a multilayer printed wiring board that can be easily densified / reduced and reduced in cost, and a method of manufacturing the same. . Background art

 In recent years, multi-layer printed wiring boards have become increasingly complex and electronically multi-functional, with the need for higher density packaging and SIP (system-in-package).

There is a strong demand for high-density and high-definition wiring boards to enable the above-mentioned requirements. Also, personalization of advanced electronic devices and communication devices is progressing, and low-cost, miniaturized multilayer printed wiring boards are required.

 Usually, the lamination process of a multilayer printed wiring board consists of a lamination (lay-up) process of an insulating material and a forming press process, and a mass lamination method and a pin lamination method are well known as lamination molding. ing.

The mass lamination method is suitable for the production of low-cost printed wiring boards, since large-sized fixed-size ones can be laminated and formed, so that a large number of printed wiring boards can be obtained. However, it is usually difficult to align the inner layer pattern and the outer layer pattern, and there is a problem that it is becoming difficult to mass-produce a multilayer printed wiring board with high alignment accuracy between the layers. In particular, it requires high lamination accuracy and is difficult to apply to the production of multilayer printed wiring boards with small diameter vias, inner via holes (IVH) or fine patterns. Therefore, the mass laminating method is usually used during molding. It is used when it is not necessary to align the layers, and when alignment between the layers is necessary, it is used in the manufacture of multilayer printed wiring boards with four or less layers.

 On the other hand, when a multilayer printed wiring board is formed by performing precise alignment between wirings, a pin lamination method is usually used.

 As another conventional method for manufacturing a multilayer printed wiring board, for example, as shown in JP-A-6-224553, a mass lamination method and a pin lamination method are used in combination. There is a lamination method. Here, in the pin lamination method, a core material formed by a mass lamination method having four or less layers is used.

 The pin lamination method enables multilayering with high lamination accuracy, but has the problem of increasing the number of manufacturing steps and increasing the cost of multilayer printed wiring boards. This is because the manufacturing and material costs are higher than in the case of the mass laminating method, and the reference pins are removed after heating, pressing and forming, and the resin adhering around the reference pins is removed. This is because workability deteriorates and productivity improvement is limited.

 Also, when forming and pressing by this pin lamination method, in order to improve productivity, a large number of core materials are simultaneously laminated to form a multilayer, for example, the copper residual ratio of each double-sided copper-clad laminate, copper foil Due to differences in thickness, etc., the position of the reference hole of the pin lamination tends to shift. For this reason, there is a problem that there is a trade-off between improving the alignment accuracy between layers and improving productivity. With the progress of thinning of printed wiring boards along with the increase in the number of layers, the demand for forming wiring patterns on core materials, such as double-sided copper-clad laminates with a board thickness of 0.1 mm or less, has increased. There is a problem that it is difficult to form a wiring pattern by line etching.

As described above, it is difficult to produce a high-density / miniaturized multilayer printed wiring board at a low cost in the conventional technology. The present invention has been made in order to solve the above problems, and has as its object to facilitate high-density multilayer printed wiring boards, and to easily reduce the size and cost. Disclosure of the invention

 The multilayer printed wiring board according to the present invention has six or more wiring layers aligned with each other, and is laminated and formed only by a mass luminescence method. Here, a double-sided copper-clad laminate having a structure in which copper foil is adhered to the front and back surfaces of the insulating substrate is included as a core material for mass lamination.

 As a result, multilayer printed wiring boards with high lamination accuracy between wiring layers can be mass-produced at low cost, and electronic devices, particularly mobile devices such as mobile phones, can be made smaller, thinner, and lower in cost. This has the effect of greatly progressing.

 In the multilayer printed wiring board according to the present invention, as a hole for connecting each wiring layer, a build-up via for connecting to the outermost wiring layer, a through hole for penetrating the wiring board and connecting each wiring layer are provided. Only holes are formed. Further, the multilayer printed wiring board is used as a core material of mass lamination and is laminated and formed by mass lamination to form a multilayer. This has the effect of further increasing the density or miniaturization of the multilayer printed wiring board.

 The multilayer printed wiring board according to the present invention has, as a core material, an inner layer board provided with a positioning pattern used for positioning between wiring layers on a surface, and has a structure formed by lamination molding only by a mass lamination method. I have. The inner plate is formed of a double-sided copper-clad laminated plate having a structure in which a copper foil is adhered to the front and back surfaces of the insulating substrate.

As a result, the wiring layers, vias or through holes of the wiring board are minutely formed. Even if the thickness is reduced, the positioning between the wiring layers can be performed with high accuracy, and an effect that a high-density multilayer printed wiring board can be manufactured at low cost is produced.

 In the multilayer printed wiring board according to the present invention, the prepreg used for the insulating substrate or the mass lamination is a glass epoxy resin or a glass epoxy resin containing a glass cloth made of S glass fiber or E glass fiber.

 I

It is composed of a BT resin that includes a glass-like glass.

 As a result, the insulating substrate or the inner layer plate is strengthened, and in lamination molding using the mass lamination method, distortion due to heating and pressure or plastic deformation of the substrate that has expanded and contracted unevenly is significantly reduced. For this reason, in the alignment between the wiring layers in the process of forming the wiring layer, the area where the alignment shift occurs on the large-sized substrate is reduced, and the production yield of the multilayer printed wiring board of the present invention is reduced. The improvement is greatly improved. In addition, it is possible to further reduce the thickness of the inner layer board, and it is possible to obtain the effect of increasing the density and reducing the size of the multilayer printed wiring board.

 In the multilayer printed wiring board according to the present invention, the positioning pattern is formed by etching a copper foil, and a plurality of types of positioning patterns corresponding to alignment between wiring layers are arranged on the insulating substrate surface. .

 In the lamination molding of the mass lamination method, the above-mentioned deformation of the wiring board becomes larger as the multilayer printed wiring board becomes more multilayered. Therefore, in the positioning between the wiring layers, the effect of the deformation is reduced by sequentially using the positioning patterns arranged inside the insulating substrate in accordance with the multilayering. Then, the production yield of the multilayer printed wiring board of the present invention is improved.

The method of manufacturing a multilayer printed wiring board according to the present invention is a method of manufacturing a multilayer printed wiring board that is formed by lamination only using a mass lamination method, and in which copper foil is adhered to the front and back surfaces of an insulating substrate. Above structure of double-sided copper-clad laminate A process of forming a desired wiring pattern and a positioning pattern by etching a copper foil to form an inner layer plate, and sequentially laminating and forming a prepreg and an outer layer copper foil by mass lamination using the above inner layer plate as a core material. And multi-layering.

 This has the effect of reducing the cost of manufacturing a multilayer printed wiring board having highly accurate alignment between wiring layers and improving the yield.

 The method for manufacturing a multilayer printed wiring board according to the present invention includes:

-X-rays are detected, and a reference hole is formed in the copper foil for the outer layer or a part of the pre-preder below it based on the above positioning pattern. Then, using the reference holes for positioning between the wiring layers, the outer layer copper foil is etched to form a wiring pattern.

 As a result, there is an effect that it is possible to surely position the wiring layers in a multilayer printed wiring board using the mass lamination method.

 In the method for manufacturing a multilayer printed wiring board according to the present invention, the positioning pattern is detected by X-rays, and a through-hole for connecting the wiring layers is formed based on the positioning pattern. Also, the through-hole is used for positioning between wiring layers, and the outer layer copper foil is etched to form a wiring pattern.

 This has the effect of reducing the cost and increasing the density and size of the multilayer printed wiring board. Brief Description of Drawings

FIG. 1 is a cross-sectional view of a multilayer printed wiring board according to Embodiment 1 of the present invention in the order of manufacturing steps. FIG. 2 is a cross-sectional view of a multilayer printed wiring board in the order of the manufacturing process following the above manufacturing process.

 FIG. 3 is a sectional view of a multilayer printed wiring board according to Embodiment 2 of the present invention in the order of manufacturing steps.

 FIG. 4 is a cross-sectional view of the multilayer printed wiring board following the above manufacturing steps in the order of the manufacturing steps.

 FIG. 5 is a cross-sectional view of a multilayer printed wiring board according to Embodiment 3 of the present invention in a manufacturing process order.

 FIG. 6 is a cross-sectional view of a multilayer printed wiring board following the above manufacturing steps in the order of the manufacturing steps. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1

 1 and 2 are cross-sectional views illustrating a first embodiment of the present invention in the order of manufacturing steps. In this description, the structure of the multilayer printed wiring board of the present invention is also shown.

In FIG. 1A, first, a two-layer core substrate 1 is formed from a double-sided copper-clad laminate as follows. Here, the base material 2, which is an insulating substrate of the double-sided copper-clad laminate used in the present invention, is an epoxy material containing glass cloth made of glass fiber or BT resin. A copper foil having a thickness of about 20 m on the surface of the base material 2 is selectively etched using a resist mask formed by a well-known photolithography technique to form and position the first wiring pattern 3. Patterns 3 a and 3 b are formed on at least three places of the substrate 2. Similarly, the copper foil on the back surface of the base material 2 is Using a resist mask formed by the luffy technique, selective etching is performed to form the second wiring pattern 4 and the positioning patterns 4a and 4b. Here, the second wiring pattern 4 and the positioning patterns 4a and 4b are formed by using a well-known CCD camera alignment method in the exposure of the photolithography technology, so that the first wiring pattern 3 and the positioning patterns 3a and 3b Formed in alignment with.

 Next, by a known mass lamination method, the two-layer core substrate 1, which is the above-mentioned inner layer plate, is laminated and formed into a core material, and the two-layer core substrate 1, the pre-readers 5, 6 as shown in FIG. Then, a four-layer plate composed of copper foils 7 and 8 for the outer layer is formed. Here, the prepregs 5 and 6 are made of an epoxy resin material having a glass cloth made of S glass fiber or E glass fiber and having a thickness of 0.03 mm or more or BT resin. The thickness of the copper foils 7 and 8 is arbitrary.

 Next, the four-layer plate is seen through the copper foil 7 with X-rays to detect the positioning pattern 3a. Then, as shown in FIG. 1C, the plurality of positioning plates 3a are aligned with each other to form corresponding reference holes 9 respectively. In this case, the reference hole is formed by well-known laser processing, X-ray processing, or the like.

Next, as shown in FIG. 1D, a third wiring pattern 11 is formed by selectively etching the copper foil 7 using a resist mask formed by a known photolithography technique. In the exposure and transfer process of the photolithography technology, since the reference hole 9 can be used as a mask alignment mark to perform alignment with the photomask, the third wiring pattern 11 is different from the first wiring pattern 3. Positioning can be performed with high accuracy. The same can be said for patterns 4 and 12. In this way, a four-layer core substrate 13 having a wiring pattern with high accuracy of alignment between the layers is formed. Next, as shown in Figs. 2A and 2B, the mass lamination method was used again. And laminate molding. Here, your material is the four-layer core substrate 13. Two prepregs 14 a and 14 b and a copper foil 15 for the outer layer are laminated on the surface of the four-layer core substrate 13, and two prepregs are also provided on the back surface of the four-layer core substrate 13. 16 a, 16 b and copper foil 17 for the outer layer are laminated. This laid-up insulating material is heated and pressed to form and press, and as shown in Fig. 2B, a six-layer board consisting of a four-layer core substrate 13, prepregs 14, 16 and copper foils 15, 17 To form Here, the prepregs 14 and 16 are made of an epoxy resin material or a BT resin having a glass cloth made of S glass fiber or E glass fiber and having a thickness of 0.03 mm or more. The thickness of the copper foils 15 and 17 is arbitrary.

 Next, in FIG. 2C, drilling is performed based on the positioning pattern 3b or 4b as a position reference, and the first wiring pattern 3, the second wiring pattern 4, the third wiring pattern 11 and the fourth wiring pattern 11 are formed. A through hole 18 penetrating the wiring pattern 12 and the copper foils 15 and 17 is formed. Then, after performing a copper plating with a film thickness of several m / s to several tens of m, a mask alignment with a photomask is performed based on the through hole 18 in the exposure transfer of the photolithography technology, (1) A fifth wiring pattern (19) and a sixth wiring pattern (20) aligned with the second wiring pattern (3), the second wiring pattern (4), the third wiring pattern (11), and the fourth wiring pattern (12) are formed. In the subsequent steps, surface treatment using a solder resist is performed to complete a 6-layer printed wiring board with 6-layer through-holes.

As described above, the first major feature of the present invention is that a two-layer core board is formed from a double-sided copper-clad laminate, and this is used as a core material to perform lamination molding by a mass lamination method to form a four-layer core board. The lamination molding by the mass lamination method is sequentially applied, such that the lamination molding by the mass lamination method using the four-layer core substrate as a core material to form a six-layer material. There is stratification. The second major feature of the present invention is that a positioning pattern is provided on an initial core material (in this case, a double-sided copper-clad laminate to a two-layer core substrate) in order to perform alignment between layers. The point is that a reference hole for alignment is formed based on this positioning pattern. The point is that all of the wiring layers to be multi-layered are positioned through the positioning pattern arranged on the surface of the core material at the earliest stage.

 Note that there are various methods for aligning the wiring layers, other than the method described in the embodiment. Here, without using the above-described reference holes, the above-mentioned positioning pattern is used as a mask alignment mark that is detected by X-rays by exposure transfer of the pattern on the photomask to the photo resist in the photolithography technology, and the photomask is directly used. There is a method of aligning the position.

 According to the present invention, the accuracy of the alignment between the multilayer wirings is greatly improved as compared with the conventional method. In particular, in the formation of six or more wiring layers, the above effects are remarkable as compared with the conventional method. In addition, since the material containing glass cloth is used for the inner layer plate, the plastic deformation of the substrate that has been unevenly expanded and contracted in the lamination molding is greatly reduced, and misalignment occurs in the alignment between the wiring layers in the process of forming the wiring layer. Area to be reduced. Therefore, the production yield of the multilayer printed wiring board is improved. Then, the thickness of the inner layer plate can be further reduced. In this way, the multi-layer printed wiring board can be easily densified, miniaturized, and inexpensively combined with the above-described effect of the multi-printed wiring board in the mass lamination method. Mass production will be possible. Embodiment 2

FIG. 3 and FIG. 4 are cross-sectional views in the order of manufacturing steps for describing the second embodiment. It is. In this embodiment, an eight-layer printed wiring board is formed. In this case as well, up to the six-layer plate 13 described in the first embodiment is formed in the same manner. That is, the six-layer plate 21 shown in FIG. 3A is almost the same as the six-layer plate 13 of FIG. 2B described in the first embodiment. However, here, the thickness of the copper foils 15 and 17 is as thick as about 20 μm. Further, positioning patterns 3c, 4c are formed further inside positioning patterns 3b, 4b. Then, in the same manner as in the first embodiment, the above-mentioned six-layer plate 21 is seen through the copper foil 15 with X-rays, and a positioning pattern 3b different from the positioning pattern 3a is detected. Then, as shown in FIG. 3B, the reference holes 22 are respectively formed by aligning the plurality of positioning patterns 3b. Here, the positioning patterns 3b and 4b are preferably formed on the same layer as the above-described positioning patterns 3a and 4a, and provided on the inner side away from the periphery of the six-layer plate 21.

 As described above, in lamination molding using the mass lamination method, the inner layer board or the wiring board undergoes plastic deformation that is unevenly expanded and contracted by heating or pressing. Furthermore, such deformation increases as the wiring board is multi-layered, and particularly increases nearer the periphery of the wiring board. Therefore, when the positioning patterns 3b and 4b arranged farther from the periphery than the positioning patterns 3a and 4a arranged on the peripheral side of the insulating substrate are used in the alignment between the wiring layers, the above-described deformation alignment is achieved. This is because the effect on the environment can be reduced.

After that, in the same manner as described with reference to FIG. 1D, the mask is aligned with the photomask based on the reference hole 22 and the copper foil 15 is etched as shown in FIG. 3C. 5 Form a wiring pattern 24. Similarly, a mask is aligned with a photomask based on the reference hole 22, and the copper foil 17 is etched to form a sixth wiring pattern 25. In this way, between each layer A six-layer core substrate 26 having wiring patterns with high alignment accuracy is formed.

 Next, as shown in FIGS. 4A and 4B, the laminate is formed again using the mass lamination method. Here, the core material is a six-layer core substrate 26. The subsequent steps are the same as those described in FIG. That is, the prepregs 27a and 27b and the copper foil 28 for the outer layer are laminated on the six-layer core substrate 26, and the prepregs 29a and 29b and the copper foil 30 for the outer layer are laminated on the back surface. Laminate. Then, forming and pressing are performed to form an eight-layer plate including a six-layer core substrate 26, prepregs 27 and 29, and copper foils 28 and 30. Here, the prepregs 27 and 29 are made of an epoxy resin material having a glass cloth made of S glass fiber or E glass fiber and having a thickness of not less than 0.03 mm or BT resin. The thickness of the copper foil 28, 30 is arbitrary.

Then, in FIG. 4C, drilling is performed based on the positioning pattern 3c or 4c as a position reference, and the first wiring pattern 3, the second wiring pattern 4, the third wiring pattern 11, and the fourth wiring pattern are formed. A through hole 31 penetrating through the wiring pattern 12, the fifth wiring pattern 24, the sixth wiring pattern 25, and the copper foils 28, 30 is formed. Then, after performing a copper plating with a film thickness of several m / s to several tens of m, a mask alignment with a photomask is performed based on the above-mentioned through hole 31 in the exposure transfer of the photolithography technology, and the first Wiring pattern 3, 2nd wiring pattern 4, 3rd wiring pattern 11, 4th wiring pattern 12, 5th wiring pattern 24, 7th wiring aligned with 6th wiring pattern 25 The pattern 32 and the eighth wiring pattern 33 are formed. In this way, an eight-layer printed wiring board having eight through-holes is completed. As described above, another feature of the present invention is that the alignment between the layers is most important. Initial core material (in this case, double-layer copper clad laminate A plurality of types of positioning patterns are arranged and provided on a substrate, and the core material becomes multilayered and the positioning patterns used from the periphery of the above-mentioned initial core material are used sequentially as the positioning patterns to be used. .

 Usually, as the multilayer printed wiring board is multi-layered, the above-mentioned deformation of the wiring board increases. However, in the present invention, in positioning between the wiring layers, the inside of the insulating substrate is adjusted from the periphery of the insulating substrate in accordance with the multilayering. By sequentially using the positioning patterns to be arranged at the same time, the influence of the deformation is reduced, and the production yield of the multilayer printed wiring board of the present invention is improved. Embodiment 3.

 FIG. 5 and FIG. 6 are cross-sectional views in the order of the manufacturing steps for explaining the third embodiment. In this embodiment, an 8-layer printed wiring board having a plurality of through holes, a one-stage build-up structure, and a method of manufacturing the same will be described. FIG. 5A is the same as that of FIG. 2C described in the first embodiment, which is referred to as a six-layer core substrate 41. Then, the six-layer core substrate 41 is used as an inner layer plate and laminated by a mass lamination method using a core material. Here, although not shown, the prepreg in the lay-up stage is an epoxy resin material having a glass cloth made of S glass fiber or E glass fiber and BT resin, and is also filled in the inner via hole 18. I do. In this way, as shown in Fig. 5B, the prepregs 42, 43, which fill the inner via hole 18, sandwiching the six-layer core substrate 41, and the copper foils 44, 45 for the outer layer are formed. An eight-layer plate formed by lamination is formed. Here, the thickness of the copper foils 44 and 45 is arbitrary, and the thickness of the prepregs 42 and 43 is not less than 0.03 mm.

Next, as shown in Fig. 6A, a drilling process is performed with the positioning pattern 3b or 4b as a position reference, and the copper foils 44, 45 and the inner layer wiring pattern are drilled. Form a through hole 4 6 through the turn. Then, as shown in FIG. 6B, using the alignment based on the through hole 46, the prepreg is moved to reach the fifth wiring pattern 19a and the sixth wiring pattern 20a, respectively. 4 2 and 4 3 are provided with respective vias for build-up. Thereafter, copper plating with a film thickness of several m to several tens / m is applied. Then, in the exposure transfer of the photolithography technology, the mask is aligned with the photomask based on the through hole 46, and the first wiring pattern 3, the second wiring pattern 4, the third wiring pattern 11, A seventh wiring pattern 47 and an eighth wiring pattern 48 aligned with the fourth wiring pattern 12, the fifth wiring pattern 19, and the sixth wiring pattern 20 are formed. Also, a seventh wiring pattern 47a, which builds up from the fifth wiring pattern 19a, and an eighth wiring pattern 48a, which builds up from the sixth wiring pattern 20a, are formed thereon. In this way, an eight-layer printed wiring board having a structure having a plurality of through holes and a one-stage build-up is completed.

 In this manner, in the present invention, it is easy to connect through the through holes between the multi-layered wirings or to form a gap between the wirings, and it is possible to further increase the density and miniaturization of the multi-layer printed wiring board with low cost. Can be formed. In addition, multilayer printed wiring boards having high alignment accuracy between wiring layers can be manufactured at low cost, and the miniaturization and cost reduction of portable devices such as mobile phones will be greatly advanced.

In the embodiment of the present invention, in the lamination molding of the mass lamination method, two pre-predas are laid up and down on the core material respectively, but the number is not limited. Further, the present invention can be similarly applied to formation of an instantaneous poser used for a chip size-package (CSP). INDUSTRIAL APPLICABILITY As described above, the multilayer printed wiring board according to the present invention enables both high density / miniaturization and low cost. We will also provide inexpensive multilayer printed wiring boards for use in advanced personalized electronic and communication equipment.

Claims

The scope of the claims 1.6 Multi-layer printed wiring board characterized by having at least six wiring layers aligned with each other and being laminated and formed only by the mass lamination method 2. The multilayer printed wiring board according to claim 1, wherein a double-sided copper-clad laminate having a structure in which copper foil is adhered to the front and back surfaces of an insulating substrate is included as a core material of mass lamination. . 3. As holes for connecting each wiring layer, only build-up vias for connecting to the outermost wiring layer and through holes for penetrating the wiring board and connecting each wiring layer shall be formed. 3. The multilayer printed wiring board according to claim 2, wherein: 4. A multilayer printed wiring board, characterized in that the multilayer printed wiring board according to claim 3 is used as a core material and is laminated and formed only by a mass luminescence method. 5. A multilayer printed wiring board characterized in that an inner layer board having a positioning pattern used for positioning between wiring layers on its surface is used as a core material, and is laminated and formed only by a mass lamination method. 6. The inner layer plate is formed from a double-sided copper-clad laminate having a structure in which copper foil is adhered to the front and back surfaces of an insulating substrate, and the positioning pattern is formed by etching the copper foil. Claim 5 characterized by the following: Printed wiring board. 7. The prepreg used for the insulating substrate or mass lamination is made of a glass epoxy resin containing a glass cloth made of S glass fiber or E glass fiber or a BT resin containing the glass cloth. 7. The multilayer printed wiring board according to claim 6, wherein 8. The multilayer printed wiring board according to claim 6, wherein a plurality of types of positioning patterns are arranged on the surface of the insulating substrate so as to correspond to alignment between wiring layers. 9. It has six or more wiring layers, and has a built-in via for connecting to the outermost wiring layer and a through hole for connecting each wiring layer through the wiring board. 7. The multilayer printed wiring board according to claim 6. 10. A method for producing a multilayer printed wiring board, which is formed by lamination only using the massalumination method, wherein the copper foil is a double-sided copper-clad laminate having a structure in which copper foil is adhered to the front and back surfaces of an insulating substrate. To form a desired wiring pattern and positioning pattern to form an inner layer plate, and including the inner layer plate as a core material, sequentially forming and laminating a pre-preda and an outer layer copper foil in a mass lamination method to form a multilayer. A method for manufacturing a multilayer printed wiring board, comprising: 1 1. The positioning pattern is detected by X-rays, and a reference hole is formed in the copper foil for the outer layer or a part of the prepreg thereunder based on the positioning pattern. 10. The method for manufacturing a multilayer printed wiring board according to claim 10, wherein one step is formed. 12. The method for manufacturing a multilayer printed wiring board according to claim 11, wherein said reference hole is used for positioning between wiring layers to etch a copper foil for an outer layer to form a wiring pattern. . 13. The method according to claim 1, wherein the positioning pattern is detected by X-rays, and a through-hole for connecting between wiring layers is formed based on the positioning pattern. 7. The method for producing a multilayer printed wiring board according to item 0. 14. The method for manufacturing a multilayer printed wiring board according to claim 13, wherein the through-hole is used for positioning between wiring layers, and the copper foil for an outer layer is etched to form a wiring pattern.