WO2005005142A1 - Conductive sheet having more than one through hole or via hole - Google Patents

Abstract

A conductive sheet (1) wherein conductive layers are formed directly on both sides of an insulating substrate (2), and the one or more conductive layers existing on one side are connected electrically with conductive layers existing on the other side through a through hole or a via hole (4) opened to penetrate the insulating substrate (2). The conductive sheet (1) is characterized in that on either side of the insulating substrate (2), at least one conductive layer (3a) not connected electrically with the other conductive layers (3b, 3c) on the same side is formed, and more than one through holes or via holes (4) are formed in the parts of the insulating substrate (2) where one or more conductive layers are formed.

Description

 Specification

 Conductive sheet with two or more through holes or via holes

 Technical field

 The present invention relates to a conductive sheet. More specifically, the present invention relates to a conductive sheet that can be suitably used for substrates for semiconductors, circuit boards for electric and electronic components, various packaging, automobile parts, solar cells, antenna circuit boards, IC cards, and the like.

 Background art

 [0002] As an FPC (Flexible Printed Circuit Board) or TAB (Tape Automated Bonding) substrate used as a circuit board for electric and electronic parts and a circuit board for semiconductors, a conductive layer is formed on an insulating base. Conductive sheets having a configuration in which copper foil is bonded have been used (Patent Documents 1 and 2).

 [0003] The conductive sheet having such a configuration needs to adhere the insulating substrate and the copper foil with high adhesiveness. For example, an adhesive is applied to the insulating substrate to bond the copper foil, Alternatively, it was manufactured by applying an adhesive to a copper foil and bonding it to an insulating substrate. In order to further improve the adhesion between the insulating substrate and the copper foil, various adhesives are selected, or copper particles are adhered to the copper foil surface to form irregular projections. Have been tried.

 [0004] Although the adhesion between the two can be improved to some extent by these methods, the following problems have been pointed out in any of the above methods with the refinement of circuit patterns. In other words, when using an adhesive, the applied thickness is 1030 μm, regardless of the type of the adhesive, and the overall thickness of the conductive sheet is large. Become. When the conductive layer is etched to form a fine circuit pattern, the adhesive layer may hinder the etching. Further, when copper particles are adhered to the surface of the copper foil to form projections and depressions, the particles may prevent finer circuit patterns.

[0005] On the other hand, various methods for forming a conductive layer directly on an insulating substrate without the intervention of the above-mentioned adhesive or uneven protrusions have been studied, such as sputtering, vapor deposition, and electroless plating. Alternatively, a conductive layer formed by electroplating is known (Patent Documents 3-13). In the case where the conductive layer is formed by such a method, although the above-mentioned problem associated with the finer circuit pattern is solved, the view of the adhesion between the conductive layer and the insulating substrate is conversely observed. From the point of view, there is still room for improvement.

 Patent Document 1: Japanese Patent Application Laid-Open No. 4-286394

 Patent Document 2: JP-A-11-307933

 Patent Document 3: JP-A-11-298104

 Patent Document 4: JP-A-5-327229

 Patent Document 5: JP-A-5-267806

 Patent Document 6: JP-A-4-314395

 Patent Document 7: JP-A-2-142198

 Patent Document 8: JP-A-2-21507

 Patent Document 9: JP-A-63-177586

 Patent Document 10: JP-A-62-226689

 Patent Document 11: JP-A-53-140570

 Patent Document 12: JP-A-59-228789

 Patent Document 13: JP-A-51-60997

 Disclosure of the invention

 Problems to be solved by the invention

[0006] The present invention has been made in view of the above situation, and an object of the present invention is to improve the adhesion between the insulating substrate and the conductive layer and make the circuit pattern finer. Another object of the present invention is to provide a conductive sheet. Means for solving the problem

[0007] In the conductive sheet of the present invention, a conductive layer is directly formed on both the front and back surfaces of an insulating substrate, and one or more conductive layers present on both the front and back surfaces are opened so as to penetrate the insulating substrate. A conductive sheet electrically connected to a conductive layer present on the other surface through a through hole or via hole provided on the other surface of the insulating substrate. At least one conductive layer that is not electrically connected to the layer is formed. In a substantial portion of the insulating substrate on which one or more of the conductive layers are formed, two or more through holes or via holes are formed, and the first conductive layer is formed by sputtering or vapor deposition. And a second conductive layer formed by an electroless plating method or an electroplating method.

In the conductive sheet of the present invention, a conductive layer is directly formed on both front and back surfaces of an insulating substrate, and one or more conductive layers present on both front and back surfaces are opened so as to penetrate the insulating substrate. A conductive sheet electrically connected to a conductive layer present on the other surface through a perforated through hole or via hole, wherein both sides of the insulating substrate have the same surface. At least one conductive layer not electrically connected to another conductive layer is formed, and the conductive layer includes a conductive layer not electrically connected to a conductive layer present on the other surface. And forming at least one anchor hole that is opened so as to penetrate the insulating substrate in a substantial portion of the insulating substrate on which at least one of the conductive layers is formed; Is connected to the conductive layer on the other side With conductive layer is Hama charge connected to it nag and either a conductive layer on the wall surface or within, the second conductive layer is formed by the sputtering method or the vapor deposition method

It is characterized by including one conductive layer and a second conductive layer formed by an electroless plating method or an electroplating method.

[0009] Preferably, the anchor holes have different opening areas on both the front and back surfaces of the insulating substrate.

[0010] Further, in the conductive sheet, an anchor layer for the purpose of improving adhesion to the insulating substrate is not provided for the purpose of electrical connection, but is provided on the other side via the anchor hole. Is preferably connected to the conductive layer on the surface.

 [0011] The present invention also relates to a semiconductor product, an electric product, an electronic product, an automobile, a solar cell, an antenna circuit board, or an IC card using the conductive sheet.

 The invention's effect

[0012] The conductive sheet of the present invention has both improved adhesion between the insulating substrate and the conductive layer and finer circuit patterns, and has highly reliable electrical connectivity. It has excellent production efficiency and dimensional accuracy. [0013] Therefore, the conductive sheet of the present invention is applied to a wide range of uses such as a substrate for semiconductors, a circuit board for electric and electronic parts, various packaging, an automobile part, a solar cell, an antenna circuit board, and an IC card. be able to. That is, the conductive sheet can form a plurality of circuit patterns in a continuous form without being cut or cut into a certain size, and can be used for the above-mentioned various applications.

 Brief Description of Drawings

 FIG. 1 is a schematic sectional view of a conductive sheet of the present invention.

 FIG. 2 is a schematic plan view of a conductive sheet of the present invention.

 FIG. 3A is a schematic sectional view of an anchor hole having a conductive layer on a wall surface like a through hole.

 FIG. 3B is a schematic sectional view of an anchor hole in which a conductive layer is filled like a via hole.

 FIG. 3C is a schematic cross-sectional view of an anchor hole having different opening areas on both front and back surfaces of an insulating substrate.

 Explanation of symbols

 [0015] 1 conductive sheet, 2 insulating substrate, 3, 3a, 3b, 3c conductive layer, 4 through hole or via hole, 5 anchor hole, 6 anchor layer, 7 bent portion, 8 soldered portion, 9 tip portion.

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings of the present specification, the same reference numerals denote the same or corresponding parts.

 [0017] <Conductive sheet and its use>

As shown in FIG. 1, the conductive sheet 1 of the present invention has an insulating substrate 2 in which conductive layers 3 are directly formed on both front and back surfaces, and one or more conductive layers 3 present on both front and back surfaces are formed on the insulating substrate 2. 2 is electrically connected to the conductive layer 3 present on the other surface through a through hole or a via hole 4 that is opened so as to penetrate through the through hole 2 as shown in FIG. The insulating substrate 2 has a structure in which at least one or more conductive layers 3a that are not electrically connected to other conductive layers 3b and 3c on the same surface are formed on both front and back surfaces. To do. FIG. 1 is a schematic sectional view of a portion where the conductive layer 3a of FIG. 2 is formed.

The conductive sheet of the present invention having such a configuration is suitable for a substrate for a semiconductor, a circuit board for electric and electronic parts, various packaging, an automobile part, a solar cell, an antenna circuit board, an IC card, and the like. Can be used. Therefore, the present invention also relates to various semiconductor products, electric products, electronic products, automobiles, solar cells, antenna circuit boards, or IC cards using such a conductive sheet. Hereinafter, each configuration of the conductive sheet of the present invention will be described.

[0019] <Insulating substrate>

 As the insulating substrate used as the substrate of the conductive sheet of the present invention, any conventionally known substrate that can be used for this kind of application can be used without any particular limitation. In particular, a film having a small thickness is preferable. This is because it is suitable for forming a conductive layer to be described later and can be processed into a long continuous material such as a roll, thereby improving production efficiency.

 Examples of such an insulating substrate include polyesters such as PET and PEN, polyimides, aramides, polysulfones, polyetherimides, polyphenylene oxides, liquid crystal polymers, glass fiber reinforced epoxy resins, and phenols. The ability to name films such as resins and acrylic resins. Among these, it is particularly preferable to use a film made of a polyimide glass fiber reinforced epoxy resin having excellent flexibility and high performance.

 It is to be noted that the film referred to here is preferably a film having a thickness of 4-1300 μΐη, preferably about 12-50 μm. If it is less than 4 / im, the strength may be too weak to be processed, and if it exceeds 300 / im, it may hinder the formation of a conductive layer for through holes, via holes, or anchor holes as described later. Because there is.

 [0022] Further, as described above, the shape of the insulating substrate is particularly suitable for a film-like force. A continuous form is acceptable. In the present invention, it is preferable to use a long continuous material such as a roll from the viewpoint of the processing efficiency in the production.

 [0023] <Sulhole>

In the present invention, the through hole is such that it physically penetrates the front and back of the insulating substrate. The conductive layers formed on both the front and back surfaces of the insulating substrate can be electrically connected to each other through the through holes.

 In the present invention, it is preferable to form a conductive layer described later after forming the through hole in the insulating substrate. This makes it possible to integrally form the conductive layers on both the front and back surfaces of the insulating substrate and the conductive layers in the through holes, thereby contributing to an improvement in production efficiency and a highly reliable electrical connection. Can be guaranteed.

 [0025] The shape of such a through hole is not particularly limited as long as it penetrates the front and back surfaces of the insulating substrate. For example, the through hole may have a circular or polygonal cross section. The through hole preferably has an inner diameter of 5 to 300 zm, preferably 10 to 200 zm. If the inner diameter is less than 5 xm, drilling becomes difficult and the processing cost increases, and if it exceeds 300 μm, the diameter of the through hole becomes too large with respect to the length of the conductive layer in the width direction, and effective circuit space is secured. And problems with electrical connections. Therefore, it is more advantageous in circuit design to form the through hole with a smaller inside diameter without increasing the processing cost.

 [0026] In addition, such through holes are formed in an amount of 2 or more, preferably 2 to 5, more preferably 2 to 3, for each conductive layer present in the form of an island on the surface of the insulating substrate. It is preferably formed in a substantial part of the insulating substrate described above. If only one through hole is formed for each conductive layer present in the shape of an island, there is a problem in the adhesion between the conductive layer and the insulating substrate, and also a problem in the electrical connectivity. is there. If too many through holes are formed, the area of the through holes occupying the conductive layer becomes large, thereby reducing the degree of freedom in circuit design and the processing efficiency. It is preferable to make up to about 5 per hit.

 Here, an island-shaped conductive layer refers to each conductive layer that is not electrically connected to another conductive layer on the same surface on either of the front and back surfaces of the insulating substrate. ,And Umono.

That is, as shown in FIG. 2, at least on the front and back surfaces of the insulating substrate 2, at least a conductive layer 3a that is not electrically connected to other conductive layers 3b and 3c on the same surface is provided. One or more of the conductive layers (in FIG. 2, at least the conductive layer 3a or the conductive layer 3a). It is preferable that two or more of the above-mentioned through holes are formed in a substantial part of the insulating substrate on which the layers 3b and 3c) are formed. By forming two or more through-holes per one conductive layer existing in an island shape, the reliability of the conductive layer with respect to the electrical connection is increased and the adhesion to the insulating substrate is also increased.

[0029] Such a through hole can be formed by any conventionally known hole forming method (drilling method) without any particular limitation. For example, CO laser,

 2

Holes are formed so as to penetrate the insulating substrate by means of various lasers such as a YAG laser and an excimer laser, and drilling, punching, and pressing. In particular, when the inner diameter of the through hole is smaller than 80 μm, it is preferable to open the hole by using various lasers.

 [0030] <Beer Honoré>

 The via hole in the present invention is a small hole provided so as to physically penetrate the front and back of the insulating substrate, and is formed on both the front and back surfaces of the insulating substrate through this via hole. Can be electrically connected to each other. As described above, the via hole has the same function as the through hole, and the through hole takes a form in which a conductive layer is formed only on the wall surface and a hollow portion remains in the center. The via hole is different in the form in that the inside of the hole is entirely filled with a conductive layer and has no hollow portion.

 [0031] In the conductive sheet of the present invention, whether the conductive layers on the front and back surfaces of the insulating substrate are electrically connected through through holes or electrically connected through via holes depends on the shape of the circuit pattern, They can be arbitrarily selected depending on the size and the like, and both can be formed alone or in combination.

 [0032] In the present invention, as in the case of the through hole, it is preferable to form the via hole on the insulating substrate and then form the conductive layer described later. This makes it possible to integrally form the conductive layer on both the front and back surfaces of the insulating substrate and the conductive layer filled in the via hole, thereby contributing to an improvement in production efficiency and providing a highly reliable electrical device. Connection can be guaranteed.

The shape of such a via hole is not particularly limited as long as it penetrates the front and back of the insulating substrate. For example, the cross-sectional shape may be circular or polygonal. Wear. The via hole has an inner diameter of 5-100 / im, preferably 10-25 / im. If the inner diameter is less than 5 / m, drilling becomes difficult and the processing cost increases, and if it exceeds 100 μΐη, it takes a long time to fill the inside of the hole with the conductive layer, resulting in poor production efficiency. Will be. It should be noted that it is more advantageous in circuit design to form such via holes with a smaller inner diameter as long as the processing cost does not increase.

 [0034] In addition, the number of such via holes is 2 or more, preferably 25, and more preferably 23 per conductive layer existing in the form of an island on the surface of the insulating substrate. It is preferably formed on a substantial portion of the insulating substrate. If only one via hole is formed for each conductive layer existing in the shape of an island, there is a problem in the adhesion between the conductive layer and the insulating substrate and also a problem in the electrical connectivity. is there. Also, if a large number of via holes are formed, the area of the via holes in the conductive layer becomes large, and the degree of freedom in circuit design is reduced, and the processing efficiency is also reduced. It is preferable to use up to about five per conductive layer. When the via hole is formed together with the through hole, the total number of both is preferably 2 or more, preferably 2-5, and more preferably 2-3.

 Here, the conductive layer existing in an island shape refers to the same conductive layer as described above. That is, as shown in FIG. 2, at least one or more conductive layers 3a that are not electrically connected to the other conductive layers 3b and 3c on the same surface are provided on both front and back surfaces of the insulating substrate 2. In a substantial portion of the insulating substrate where one or more of the conductive layers (in FIG. 2, at least the conductive layer 3a or the conductive layers 3b and 3c) are formed, two or more of the via holes are formed. It is preferable to By forming two or more via holes per conductive layer existing in an island shape in this way, the conductive layer increases the reliability with respect to the electrical connectivity and the adhesion to the insulating substrate. Enhanced.

 [0036] Such a via hole can be opened by any conventionally known opening method (drilling method) without any particular limitation. For example, CO laser,

 2

Holes are formed by various lasers such as a YAG laser and an excimer laser so as to penetrate the insulating substrate.

<Conductive layer> The conductive layer of the present invention is formed directly on both the front and back surfaces of the insulating substrate, and one or more conductive layers existing on both the front and back surfaces are opened so as to penetrate the insulating substrate. It is electrically connected to the conductive layer on the other surface via via holes (see Fig. 1). Further, at least one or more conductive layers that are not electrically connected to other conductive layers on the same surface are formed on both front and back surfaces of the insulating substrate (see FIG. 2). As described above, two or more through holes or via holes are formed in a substantial portion of the insulating substrate on which one or more are formed.

 [0038] The conductive layer of the present invention may include a conductive layer that is not electrically connected to the conductive layer present on the other surface of the insulating substrate. Can be included. That is, the conductive layer may include those in which a through hole or a via hole is not formed in a substantial portion of the insulating substrate on which the conductive layer is formed. Therefore, both the through hole or the via hole and the anchor hole may be included. Some are formed, and some are formed only one of them.

 [0039] Such a conductive layer is formed directly on both the front and back surfaces of the insulative substrate, and also formed on the wall surface of the through hole or the like (including an anchor hole to be described later, the same applies hereinafter). (The same applies to the following), which is formed so as to fill the inside. Further, the conductive layer is formed so as to have the same configuration on the wall surface such as the through hole or the inside of the via hole and the front and back surfaces of the insulating substrate.

 Here, that the conductive layer is formed directly on the insulating substrate means that the conductive layer is formed so as to be in direct contact with the insulating substrate without using an adhesive or the like. It is formed so as to be in direct contact with the insulating substrate not only on the front and back surfaces but also in through holes and via holes. As a result, the present invention has succeeded in solving various problems caused by the use of the adhesive in the related art, and in particular, has enabled finer circuit patterns.

The conductive layers on the front and back surfaces of such an insulating substrate are electrically connected to each other through through holes or via holes. Here, the term “electrically connected through through holes” specifically means In general, the conductors directly formed on the front and back surfaces of the insulating substrate This means that the conductive layer is electrically connected by the conductive layer of the same configuration formed on the wall surface of the through hole. The term “electrically connected via the via hole” means that the conductive layer formed directly on the front and back surfaces of the insulating substrate is electrically connected by the conductive layer of the same configuration filled inside the via hole. It means connected. As described above, since the conductive layer on the wall surface of the through hole or the conductive layer filling the inside of the via hole and the conductive layer on the front and back surfaces of the insulating substrate have the same configuration, highly reliable electrical connection is possible. It becomes.

[0042] The composition of such a conductive layer is not particularly limited as long as it has an electric conductivity function. However, Cu, Ni, Cr, Ag, Au, Zn, Ti, Pd, Sn, Bi And at least one metal selected from the group consisting of Co and Co or an alloy containing at least one of the above metals, and may be formed as a single layer, and may have the same composition or different compositions. Can be formed by laminating a plurality of layers.

 [0043] The fact that the conductive layer has the same configuration on the wall surface such as a through hole or the inside of a via hole and on the front and back surfaces of the insulating substrate means that the above-mentioned laminated state is the same, It does not necessarily mean that the thicknesses of the layers are the same.

 Further, it is preferable that the conductive layer is formed in the same step on the wall surface of the through hole or inside the via hole and on both the front and back surfaces of the insulating substrate. In addition, a method of forming in the same step will be described later.

 [0045] Such a conductive layer can include a first conductive layer formed by a sputtering method or a vapor deposition method, and a second conductive layer formed by an electroless plating method or an electroplating method. In the present invention, the first conductive layer and the second conductive layer may be formed as a single layer or a plurality of layers, respectively, to form a conductive layer.

 <First conductive layer>

The first conductive layer of the present invention is formed directly on the insulating substrate, and the above-mentioned metal or an alloy containing at least one metal, more preferably Cu, Ag, Sn, Ni, Cr, Co and T can be formed by sputtering or vapor deposition of at least one metal selected from Zn or an alloy containing at least one metal. This first conductive layer has a function as a so-called underlayer for forming a second conductive layer described later. And has the function of improving the adhesion of the second conductive layer to the insulating substrate.

 [0047] Such a first conductive layer is preferably formed to a thickness of 500 to 5000A, preferably 1000 to 3000A. If it is less than 500 A, the effect of improving the adhesion of the second conductive layer described later cannot be sufficiently exhibited, and even if it exceeds 5000 A, the adhesion of the second conductive layer will not be substantially different and disadvantageously in terms of cost. .

 [0048] As described above, such a first conductive layer can be formed by forming one layer (single layer) or by laminating two or more layers (a plurality of layers). The ability to have

 When two or more first conductive layers are stacked, first, at least one metal selected from Ni, Cr, Ti, Zn, or Co or an alloy containing at least one metal on the insulating substrate Are laminated, and at least one metal selected from Cu, Ag, Sn or Zn or an alloy containing at least one metal is preferably laminated.

 [0050] The above-mentioned at least one metal selected from Cu, Ag, Sn or Zn or an alloy containing at least one such metal has good electrical properties and excellent adhesion to the second conductive layer, In addition, since it is relatively inexpensive, it is advantageous to use it for such an application, but it has a problem that it is easily oxidized and the electric characteristics are impaired. Therefore, in order to solve this oxidation problem, at least an oxidation-resistant metal such as Ni, Cr, Ti, Zn or Co selected under such a layer (ie, between the insulating substrate). By forming one kind of metal or an alloy containing at least one such metal, it is possible to prevent the deterioration of the adhesive force over time due to oxidation.

 [0051] The thickness of such a layer made of a metal having oxidation resistance is preferably 10 to 200A, more preferably 3070A. If it is less than 10 A, the effect of oxidation resistance may not be sufficiently exhibited, and if it exceeds 200 A, etching may be difficult when forming a circuit pattern.

 [0052] <Second conductive layer>

The second conductive layer of the present invention is formed on the first conductive layer, and as the conductive layer, the metal described above or an alloy containing at least one metal, more preferably Cu, Ag, Sn, Ni, and B are formed by applying at least one metal selected from Zn or an alloy containing at least one metal by an electroless plating method or an electroplating method. Among these metals or alloys, Cu is particularly preferred, and those formed by electroplating copper sulfate are particularly preferred. This is because it is inexpensive, has high reliability in electrical connection, and has excellent production efficiency.

 [0053] Such a second conductive layer mainly has an effect of imparting electric conductivity and mechanical strength by being formed thicker than the first conductive layer. In addition, since the second conductive layer has electrical conductivity, it can also function as a capacitor if it is arranged so as to face both sides of the insulating substrate.

 [0054] Such a second conductive layer is preferably formed with a thickness of 0.550 x m, preferably 4-1 38zm. If it is less than 0, there is a problem that sufficient electrical conductivity cannot be obtained and the electrical resistance becomes too large. Even if it exceeds 50 μm, there is no significant difference in electrical conductivity, which is disadvantageous in cost.

 As described above, such a second conductive layer can be formed as a single layer (single layer) or a laminate of two or more layers (a plurality of layers). The ability to have

 The second conductive layer is preferably formed by using an electroplating method when forming a relatively thick layer, and an electroless plating method when forming the second conductive layer relatively thin. It is preferable to adopt and form.

 [0057] <Anchor Honoré>

 The anchor hole in the present invention is a force that is a small hole provided so as to physically penetrate the front and back of the insulating substrate. Unlike the above-described through hole or via hole, the conductive layer is formed through the anchor hole. There is no electrical connection with the conductive layer present on the other surface of the insulating substrate.

[0058] Such an anchor hole has a function of improving the adhesion of the conductive layer to the insulating substrate by having a conductive layer on the wall surface or filling the inside with the conductive layer. To play. For example, as shown in FIG. 3A, the conductive layer 3 can be formed on the wall surface of the anchor hole 5 like a through hole, and as shown in FIG. 3B. As described above, the inside of the anchor hole 5 can be filled with the conductive layer 3 like a via hole.

 [0059] In the present invention, it is preferable to form the conductive layer after forming the anchor hole in the insulating substrate as in the case of the through hole and the via hole described above. This makes it possible to integrally form the conductive layers on both the front and back surfaces of the insulating substrate and the conductive layer in the anchor hole, thereby contributing to an improvement in production efficiency, as well as improving the efficiency of the conductive layer and the insulating substrate. Adhesion between them can be further improved.

 [0060] The shape of such an anchor hole is not particularly limited as long as it penetrates the front and back surfaces of the insulating base, but preferably the opening areas of the front and back surfaces of the insulating base are different. Is preferred. That is, as shown in FIG. 3C, the insulating area of the conductive layer is reduced by making the opening area of the surface on which the conductive layer is formed smaller than the opening area of the surface on which the conductive layer is not formed. The adhesion to the conductive substrate can be further improved.

 [0061] The inner diameter of such an anchor hole is preferably 5 to 300 µm, and more preferably 10 to 200 µm. If the inner diameter is less than 5 / m, drilling becomes difficult and the processing cost increases, and if it exceeds 300 μ ア ン カ ー η, the diameter of the anchor hole becomes too large with respect to the length in the width direction of the conductive layer. Problems may occur in securing space and electrical connection. Therefore, it is more advantageous in terms of circuit design to form the inner diameter of the anchor hole as small as possible without increasing the processing cost.

 [0062] Further, such an anchor hole is formed in an island shape on the surface of the insulative substrate at one or more, preferably one to thirty, more preferably three to ten, and more preferably three to ten, conductive layers. It is preferable to form and form a substantial part of the insulating substrate. If an anchor hole is not formed at all for each conductive layer existing in the shape of an island, there may be a problem in the adhesion between the conductive layer and the insulating substrate, and if too many anchor holes are formed, However, since the area of the anchor hole in the conductive layer increases, the degree of freedom in circuit design decreases, and the processing efficiency also decreases.Therefore, up to about 30 conductive layers per island-shaped conductive layer Les, which you prefer.

Here, the conductive layer existing in an island shape means the same conductive layer as described above. That is, as shown in FIG. 2, on both front and back surfaces of the insulating substrate 2, the same surface is provided. At least one or more conductive layers 3a not electrically connected to the other conductive layers 3b and 3c are formed, and at least one of the conductive layers (in FIG. 2, at least the conductive layer 3a or the conductive layers 3b, 3c It is preferable that one or more of the anchor holes 5 are formed in a substantial portion of the insulating substrate on which the above ()) is formed.

Further, it is particularly effective to form such an anchor hole 5 in the insulating substrate 2 at the bent portion 7 of the conductive layer or at a portion corresponding to a long linear place. It is also effective to form the conductive layer in a place where the width is small, or in a portion corresponding to the soldered portion 8 or the like. This is because, in such a place of the conductive layer, the adhesion to the insulating substrate tends to be insufficient.

 [0065] Such an anchor hole can be opened by any conventionally known opening method (drilling method) without any particular limitation. For example, holes are formed so as to penetrate the insulating substrate by means of various lasers such as a CO laser, a YAG laser, an excimer laser, and the like, drills, punches, presses, and the like. In particular, when the inner diameter force of the through hole is smaller than ¾0 μΐη, it is preferable to open the hole by using various lasers.

 [0066] <Anchor layer>

 The anchor layer of the present invention is formed not for the purpose of electrical connection but for the purpose of improving the adhesion of the conductive layer to the insulating substrate. As shown in FIGS. 3A and 3B, the anchor layer 6 is connected to a conductive layer existing in the same plane as the force connected to the conductive layer 3 on the other surface via the anchor hole 5. Never.

 [0067] Such an anchor layer has the same composition and the same laminated structure as the conductive layer (may have the same composition and thickness as the first conductive layer and the second conductive layer). After the anchor holes are formed, it is preferable that the holes are formed in the same step as the conductive layer, and then formed by etching or the like so as to be insulated from the conductive layer in the same plane. Note that a detailed method for forming the conductive layer will be described below.

 [0068] Method of forming conductive layer>

The conductive layer according to the present invention is characterized in that, after a through hole, a via hole or an anchor hole is formed in the insulating substrate, the front and back surfaces of the insulating substrate and the wall surfaces of the through hole and the like (including anchor holes, the same applies hereinafter). Or via holes (including anchor holes, hereinafter the same) It is preferable that they are formed in the same step inside the same step. This makes it possible to integrally form the conductive layers on both the front and back surfaces of the insulating substrate and the conductive layers inside the wall surfaces such as through holes or via holes, thereby contributing to the improvement of production efficiency. Reliable electrical connections can be guaranteed. It also contributes to improving the adhesion between the conductive layer and the insulating substrate.

 Here, that the conductive layer is formed in the same step means that the conductive layer is formed simultaneously and integrally on both the front and back surfaces of the insulating substrate and the wall surface such as the through hole or the inside of the via hole. It is meant that it is formed in a typical way.

 [0070] That is, for example, when the conductive layer includes a first conductive layer and a second conductive layer, first, the first conductive layer is formed on both the front and back surfaces of the insulative base and the wall surface such as the through hole or the inside of the via hole. And a second conductive layer is formed on the first conductive layer simultaneously by an electroless plating method or an electroplating method. The case where it is formed integrally is included. When the inside of the via hole or the like is simultaneously and integrally filled with the conductive layer on the front and back surfaces of the insulating substrate, the first conductive layer is mainly formed on the wall surface of the via hole and formed on the first conductive layer. The hole is filled with the second conductive layer to be filled, and the cavity is filled.

 As described above, when the conductive layer includes the first conductive layer and the second conductive layer, or when the respective layers are stacked in a plurality of layers, each layer is formed simultaneously and integrally as described above. As far as possible, the conductive layers are formed in the same step.

In the case where the conductive layer is formed by a sputtering method or a vapor deposition method, and when the front and back surfaces of the insulating substrate cannot be treated at one time due to the characteristics of a processing apparatus or the like, the front and rear surfaces are different. Even if a conductive layer is formed by performing two operations on each of the back surfaces, the conductive layers on both the front and back surfaces and the conductive layers inside the wall surfaces such as through holes or via holes are formed in the same process. In this case, the conductive layer inside the wall such as the through hole or the via hole is considered to be formed to the middle height (depth) of the hole by each of these two operations. It is considered that the above operation forms a conductive layer on the entire wall surface such as a through hole or via hole. Further, even if the conductive layer is weighted and stacked at the middle height (depth) portion of the hole, It is assumed that the configuration is the same as the configuration of the conductive layer on the surface of the insulating substrate.

 As described above, by forming the conductive layer in the same step, conventionally, a conductive layer is first formed on both the front and back surfaces of the insulating substrate, then a through hole or a via hole is opened, and then the through hole is formed again. Compared to the method in which the conductive layer is formed on the wall surface or inside the via hole, the number of steps for forming the conductive layer can be halved, thereby greatly improving the production efficiency. . Since the resilient force is integrally formed in the same process, a highly reliable connection effect can be obtained.

 In the conventional method as described above, it is difficult to selectively form the conductive layer only on the wall surface of the through hole or inside the via hole, and it is inevitably formed in advance on the insulating substrate. The conductive layer is formed so as to extend over the conductive layer. However, in this case, the thickness of the conductive layer is weighted and formed, and when the thickness of the conductive layer on the insulating substrate is increased in this manner, processing for forming a circuit is difficult and dimensional accuracy itself is deteriorated. . On the other hand, according to the forming method of the present invention, the thickness of the conductive layer can be reduced as much as possible without the weight of the conductive layer being weighted, which contributes to finer circuit patterns. Dimensional accuracy may not deteriorate.

 Since the conductive layer is not formed on both the front and back surfaces of the insulating substrate via the anchor hole, the conductive layer existing on the surface where the conductive layer is not formed is removed by etching or the like. You. Alternatively, a mask may be preliminarily applied to a corresponding portion of the anchor hole so that the conductive layer is not formed at that portion. Further, as described above, the anchor layer can be formed by leaving such a conductive layer partially instead of completely removing it by etching.

 [0076] Others>

 An alignment mark can be formed on the insulating substrate of the present invention. The alignment mark serves as a reference for determining a predetermined position of a through hole, a via hole, and the like, and is usually formed at both ends of the insulating substrate (where a through hole, a via hole, and the like are provided, a position, and a position). It is suitable.

[0077] Such an alignment mark can determine a predetermined position such as a through hole or a via hole by optical, electronic, magnetic, visual, or other reading means. Any material may be used as long as it is formed, and the method of forming the material is not particularly limited. For example, in the case of visual reading, it is preferable that the alignment mark is formed by making holes at both ends of the insulating substrate so as to penetrate the substrate. The holes (referred to as alignment holes) are more preferably continuously opened at regular intervals. By adopting such a configuration, the position of the through hole can be more easily determined.

 The size of such an alignment hole is usually preferably about 5 μm 3 mm, and the hole can be formed by various lasers, drills, punches, presses, or the like. When such an alignment hole is smaller than 80 x m, it is preferable to use various lasers.

 [0079] Further, like the above-mentioned through hole, a conductive layer is formed on the inner wall surface of such an alignment hole.

 On the other hand, a bonding layer for an integrated circuit and an oxidation preventing layer can be formed on the conductive layer. The integrated circuit bonding layer has a function of facilitating the mounting of the integrated circuit (IC chip or LSI) on the insulating substrate, and directly electrically connects the conductive layer to the integrated circuit. is there. The antioxidant layer has a function of preventing the conductive layer from being oxidized and exhibiting no conductivity, or preventing poor adhesion to the insulating substrate.

 [0081] Such a layer is preferably made of at least one metal selected from the group consisting of Sn, Ni, Au, Ag, Zn, and Cr, or an alloy containing at least one metal.

[0082] In the case of a coupling layer for an integrated circuit, the thickness is preferably 0.2 to 15 zm, more preferably 0.5 to 5 zm. If it is less than 0.2 zm, the effect of easy mounting of integrated circuits will not be exhibited, and even if it exceeds 15 xm, the cost will be much higher than the effect of easy mounting of integrated circuits. Not preferred.

In the case of the antioxidant layer, the thickness is preferably 0.012 μm, and more preferably 0.051 μm. If the value is less than 0.01 zm, the above-mentioned effects will not be exhibited, and if the value exceeds 2 xm, the cost will increase rather than the above-mentioned effects. It ’s not.

 [0084] Such a layer may be formed as a single layer or a plurality of layers on the entire surface of the conductive layer or a portion such as a bump by any one of an electroless plating method, an electroplating method, and a chromate method. The ability to generate S.

 Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0086] Example 1

 The conductive sheet of the present invention will be described with reference to FIGS.

First, as an insulating substrate 2, a polyimide finolem (trade name: Avical, manufactured by Kanebo) having a thickness of 50 μππ, a width of 250 mm, and a length of 100 m was set on a CO laser processing machine (manufactured by Mitsubishi Electric). .

 2

 Then, as shown in FIGS. 1 and 2, a 80-meter-diameter through-hole was passed through the polyimide film at a portion corresponding to the front end 9 of the conductive layer 3a by this processing machine. Holes were formed as one set (the distance between holes was 120 μm), and through holes were also formed in portions corresponding to predetermined positions of the conductive layer 3b.

At the same time, two sets of anchor holes 5 each having an inner diameter of 50 μm were formed at two corresponding portions of the conductive layer 3a corresponding to the bent portions 7 so as to penetrate both sides of the polyimide film. The distance is 100 _βm ), and an anchor hole 5 having an inner diameter of 50 / im is formed in a portion corresponding to the soldered portion 8 of the conductive layer 3a so as to penetrate both sides of the polyimide film. Was opened as one set of three holes (the distance between each hole was 100 μm). Further, anchor holes 5 were similarly formed in portions corresponding to predetermined positions of conductive layers 3b and 3c.

 Subsequently, the insulating substrate 2 that has been subjected to the opening treatment by the CO laser as described above is

 2

 Then, the following treatment was carried out in order to remove the carbide formed in the hole and its periphery during the treatment. That is, the insulating substrate 2 was set in a dismirror apparatus, immersed in an immersion bath of a 50 g / 1 aqueous solution of potassium permanganate at a liquid temperature of 60 ° C. for 60 seconds, and washed with pure water five times. .

After that, a neutralization treatment was further performed by immersing in a 4% sulfuric acid immersion bath at a liquid temperature of 40 ° C. for 2 minutes, and washing with pure water was repeated five times. Next, the high-performance filter Draining was performed with dry air at 105 ° C passed through (the size of the opening of the filter was 0.5 μm or less), and the carbides generated above were removed by sufficient drying. Thereafter, the insulating substrate 2 was taken out of the dismearing device.

 [0091] Next, one end of the insulating substrate 2 from which the carbide had been removed as described above was set on a delivery shaft of a sputtering device, and the other end was set on a winding shaft. On the other hand, to the four targets of this sputtering apparatus, Ni was attached as target No. 1 and Cu was attached as target No. 24, respectively.

[0092] Then close the chamber one said sputtering apparatus, a vacuum degree of 1 X 10 by the vacuum pump - After a ⁴ Pa, the injection amount of argon gas is the target No. 1, fitted with a Ni 180c cZ min, target current 0. 6kWZdm ^2, and is for the target No. 2-4 fitted with a Cu injection volume each 250 cc / min argon gas to sputter these metals under matter conditions of the target current each 1. 2kWZdm ² Thus, the first conductive layer was formed directly on one surface of the insulating substrate. Then, the vacuum state of the sputtering apparatus was released.

 Subsequently, the insulating substrate 2 is turned upside down so that the same first conductive layer as described above can be formed on the surface of the insulating substrate 2 on which the first conductive layer is not formed. Then, it was set again in the sputtering apparatus. Then, the same first conductive layer as described above was directly formed on the other surface of the insulating substrate by performing sputtering under the same conditions as described above.

 As a result, the first conductive layer is formed directly on both the front and back surfaces of the insulating substrate 2 and the wall surfaces of the through hole and the anchor hole 5, and the first conductive layer is formed by first forming the Ni layer on the insulating substrate 2. They are stacked and a Cu layer is stacked on them. This configuration has the same configuration on both the front and back surfaces of the insulating substrate and the wall surfaces of the through hole and the anchor hole 5.

 [0095] Sampling was performed at 10m, 50m, and 90m from one end of the insulating substrate 2, and the cross section was cut using a FIB device to measure the thickness. Both the front and back sides of the insulating substrate were 70 A for the Ni layer and 2900 A for the Cu layer

[0096] Subsequently, after washing with pure water several times, the first guide was applied to both the front and back surfaces as described above. The insulating substrate 2 on which the electric layer was formed was set in a continuous plating apparatus, and the electric plating was performed under the following conditions. That is, first, the insulating substrate is immersed continuously in an acid activation tank filled with 7% sulfuric acid at a liquid temperature of 28 ° C for 60 seconds, so that the first conductive layer is subjected to an acid activation treatment. Was performed.

[0097] Next, after the washing with pure water was repeated three times, the plating solution (copper sulfate 100 g / l, sulfuric acid 160 g / l, chlorine 60 ppm, and toppertina 380H (manufactured by Okuno Pharmaceutical Co., Ltd.)) was added to the plating bath of the above apparatus. filled ones) consisting Locc / 1, the insulating substrate 1. is continuously immersed at a moving speed of OmZ min,-out liquid temperature 28 ° C, under conditions of current density 4AZdm ² 11 minutes electrical flashes Thereby, a second conductive layer made of Cu was formed on the first conductive layer.

 [0098] Thereby, the first conductive layer is formed on both the front and back surfaces of the insulating substrate 2 and the wall surfaces of the through hole and the anchor hole 5, and the second conductive layer is formed on the first conductive layer. The conductive layer 3 was formed. The configuration of the second conductive layer is the same on both the front and back surfaces of the insulating substrate 2 and the wall surfaces of the through hole and the anchor hole 5. Accordingly, the conductive layer 3 includes a first conductive layer and a second conductive layer, and has the same configuration on both the front and back surfaces of the insulating substrate 2 and the wall surfaces of the through hole and the anchor hole 5. Layer 3 has been formed.

 [0099] Subsequently, the insulating substrate 2 on which the second conductive layer was formed was repeatedly washed with pure water five times. Next, the mixture was drained with dry air at 105 ° C. through a high-performance filter (the size of the opening of the filter was 0.5 / m or less) and dried sufficiently.

 [0100] Sampling was performed at 10m, 50m, and 90m from one end of the insulating substrate 2 on which the conductive layer 3 thus obtained was formed, and the cross section was cut using a FIB device. Then, when the thickness of the second conductive layer was measured, it was within 10 μπι ± 5% at both points (the surface of the insulating substrate and the wall surfaces of the through holes and anchor holes) for both the front and back surfaces of the insulating substrate.

[0101] In addition, peel test apparatus have use the (MODEL 1305N, Aiko one Engineering Co., Ltd.) were measured adhesion to the insulating substrate of the conductive layer, the adhesion of 3 kg / cm ² is where there is anchor holes Although the strength was shown, the adhesion strength was 0.9 kg / cm ² where there was no anchor hole. Due to this, adhesion by anchor hole The effect of improvement was confirmed.

Next, a dry film (trade name: NIT215, manufactured by Nichigo Morton) was applied as a resist on the entire surface of the second conductive layer of the insulating substrate 2 under the conditions of a temperature of 110 ° C. and a pressure of 2 kg / cm ² . Then, a resist was formed on the second conductive layer.

Subsequently, a mask representing a desired circuit pattern (designed such that a portion serving as an anchor layer remains without being etched) on both the front and back surfaces of the insulating substrate 2 is overlaid on the resist. After the alignment, exposure was performed at an amount of light of 120 mJ using an average exposure machine (manufactured by the company). Next, in order to remove the resist in the area where the circuit is not formed (the area not exposed by the mask), using a developing device, the conditions of sodium carbonate 0.5 gZl, temperature 28 ° C, spray pressure 1.5 kg / cm ² were used. The resist was removed by developing underneath. Thereafter, washing with pure water was repeated 5 times.

Next, in order to remove the conductive layer (including the first conductive layer and the second conductive layer) at the portion where the resist was removed by etching, 47% ferric chloride and 50% temperature were used using an etching apparatus. The conductive layer was removed by etching under the conditions of ° C and a spray pressure of ^2.5 kg / cm ² . After that, washing with pure water was repeated 5 times.

[0105] Then, in order to remove the resist on the conductive layer and the anchor layer that were not etched as described above, a resist stripper was used to remove 100% caustic soda, a temperature of 60 ° C, and a spray pressure of 2. Okg / cm ² . The conductive sheet 1 of the present invention was obtained by removing the resist under the conditions.

 With respect to the conductive sheet 1 thus obtained, the circuit pattern formed by the conductive layer and the positions of the through hole, the anchor hole and the anchor layer were confirmed. It was within ± 5%, which was extremely excellent in dimensional accuracy and allowed fine circuit patterns. In addition, since the conductive layers were formed simultaneously and integrally, the production efficiency was excellent.

[0107] Further, the conductive sheet has highly reliable electrical connectivity because two or more through holes are formed in a substantial part of the insulating substrate on which the conductive layer is formed. At the same time, the adhesion between the conductive layer and the insulating substrate was greatly enhanced by the anchor holes. <Example 2>

 A conductive sheet was obtained in the same manner as in Example 1 except that the inner diameter of the through hole and the inner diameter of the anchor hole were each 20 μm.

[0109] In the conductive sheet thus obtained, the through hole in Example 1 was in the form of a via hole, and the anchor hole was also filled in the inside like a via hole.

[0110] As in the case of Example 1, the conductive sheet was extremely excellent in dimensional accuracy and allowed finer circuit patterns. In addition, it has highly reliable electrical connection, the adhesion between the conductive layer and the insulating substrate is extremely enhanced by the anchor holes, and the production efficiency is excellent.

Claims

The scope of the claims  [1] A conductive layer (3) is directly formed on both the front and back surfaces of the insulating substrate (2), and one or more conductive layers (3) existing on both the front and back surfaces penetrate the insulating substrate (2). A conductive sheet (1) that is electrically connected to a conductive layer (3) on the other surface through a through hole or via hole (4) that has been opened. At least one or more conductive layers (3a) not electrically connected to other conductive layers (3b, 3c) on the same surface are formed on both front and back surfaces of 2). ), Two or more through holes or via holes (4) are formed in a substantial portion of the insulating substrate (2) on which one or more of the conductive layers (3) are formed. It comprises a first conductive layer formed by a vapor deposition method and a second conductive layer formed by an electroless plating method or an electroplating method. Conductive sheets (1).  [2] The conductive layer (3) is directly formed on both the front and back surfaces of the insulating substrate (2), and one or more conductive layers (3) present on both the front and back surfaces penetrate the insulating substrate (2). A conductive sheet (1) that is electrically connected to a conductive layer (3) on the other surface through a through hole or via hole (4) that has been opened. At least one or more conductive layers (3a) not electrically connected to other conductive layers (3b, 3c) on the same surface are formed on both front and back surfaces of 2). ) Includes a conductive layer that is not electrically connected to the conductive layer (3) on the other surface, and a substantial part of the insulating substrate (2) on which one or more of the conductive layer (3) is formed. In addition, at least one anchor hole (5) is formed so as to penetrate the insulating substrate (2), and the anchor hole (5) is formed through the anchor hole (5). Electrically connected to the conductive layer (3) existing on the other side and having the conductive layer (3) on the wall surface or the inside filled with the conductive layer (3). A conductive sheet (1), wherein the layer (3) includes a first conductive layer formed by a sputtering method or a vapor deposition method, and a second conductive layer formed by an electroless plating method or an electroplating method. 1).  3. The conductive sheet (1) according to claim 2, wherein the anchor holes (5) have different opening areas on both front and back surfaces of the insulating substrate (2). [4] Adhesion of the conductive layer (3) to the insulating substrate (2) without aiming for electrical connection The conductive sheet (1) according to claim 2, wherein the anchor layer (6) for the purpose of improvement is connected to the conductive layer (3) on the other surface via the anchor hole (5). ). [5] The conductive sheet (1) according to claim 1, wherein two or more first conductive layers are laminated.  6. The conductive sheet (1) according to claim 2, wherein two or more first conductive layers are laminated.  [7] A semiconductor product, an electric product, an electronic product, an automobile, a solar cell, an antenna circuit board, or an IC card using the conductive sheet (1) according to claim 1. [8] A semiconductor product, an electric product, an electronic product, an automobile, a solar cell, an antenna circuit board or an IC card using the conductive sheet (1) according to claim 2.