JP4180331B2 - Printed wiring board, metal plate with relief pattern for printed wiring board, and method for manufacturing printed wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a printed wiring board, and more specifically, a so-called through-conductor type printed wiring board, a metal plate with a relief pattern for a printed wiring board, and a printed circuit board, in which wiring layers are connected by a through-type conductive wiring portion. The present invention relates to a method for manufacturing a wiring board.
[0002]
[Prior art]
Conventionally, as a method of manufacturing a multilayer board, an approximately conical paste bump is press-fitted in the thickness direction of an insulating substrate to achieve electrical continuity between two wiring patterns formed on both surfaces of the insulating substrate. A general law is known. FIG. 34 is a cross-sectional view schematically showing a manufacturing process of a conventional typical conductor penetration method. In this conductor penetration method, as shown in FIG. 34 (a), for example, a printing mask (not shown) in which a plurality of through holes are drilled is overlaid on the conductor plate 101, and silver paste is applied from the upper side of this printing mask. The conductive composition such as squeegee is filled into the through-holes, and then the printing mask and the conductive plate are peeled to form substantially conical paste bump groups 102, 102,... (FIG. 34). (B)). Next, for example, an insulating material plate precursor 103 obtained by impregnating an epoxy resin into a glass fiber mat is laminated, pressed to penetrate (FIG. 34 (c)), and a copper foil 104 is laminated thereon (FIG. 34). (D)) Etching is performed to form the wiring patterns 104a and 101a to form the core material 110 (FIG. 34E).
[0003]
On the other hand, the bumped copper foils 120 and 140 similar to those shown in FIG. 34C are prepared by the same method as described above, and the insulating material is interposed between the core material 110 and the bumped copper foils 120 and 140. Insulating material plate precursors 130 and 150 similar to the plate precursor 103 are set as shown in FIG. Thereafter, pressing is performed to form a laminate 160 as shown in FIG. 34 (g), and an outermost copper foil of this laminate 160 is etched to form a wiring pattern, as shown in FIG. 34 (h). Such a multilayer printed wiring board 170 is obtained.
[0004]
[Problems to be solved by the invention]
When a paste bump group is formed on an insulating substrate on which such a wiring layer is formed, a printing mask or the like for forming the paste bump group is required. In addition, since the paste bump group formed of the conductive composition material has a variation in height, the interlayer connection may be deficient. Furthermore, since the composition is different from that of the wiring layer, cracks may occur between the compositions due to thermal factors. In addition, in order to bring the wiring layers into close contact with each other with an insulating material in the multilayering process, a wider layer is required by the thickness of the wiring layer, and at the same time, the substrate smoothness is also affected. There is a problem that it becomes an obstacle to the manufacture of the substrate. In addition, the printing method is technically regarded as the smallest bump that can be formed with a bump diameter of 0.15 mm, and it is impossible to form a bump having a diameter smaller than this, and the height of the paste bump formed by the printing method. As a result, the reliability of interlayer connection is insufficient.
[0005]
The present invention has been made to solve the above conventional problems. That is, an object of the present invention is to provide a highly reliable multilayer printed wiring board having a fine interlayer connection, a metal plate with a relief pattern for a printed wiring board, and a method for manufacturing the printed wiring board.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a printed wiring board according to the present invention includes an insulating substrate, a first surface wiring pattern disposed on one surface of the insulating substrate, and another surface of the insulating substrate. The arranged second surface wiring pattern, the first surface wiring pattern or the metal bump electrically connected to the second surface wiring pattern, and the first surface wiring pattern and the second A metal bump-attached wiring member comprising an inner layer wiring pattern arranged in parallel with the surface of the insulating substrate, the first surface wiring pattern, and the second surface wiring pattern. And an interlayer connection member electrically connected to the surface wiring pattern and / or the inner layer wiring pattern.
[0007]
In the printed wiring board, an example of the interlayer wiring member is a paste bump.
[0008]
In the printed wiring board, examples of the interlayer wiring member include a through-hole metal layer.
[0009]
Another printed wiring board of the present invention includes a core substrate, a first inner insulating layer, a first outer insulating layer, a first surface wiring pattern, the first inner insulating layer, and the outer insulating layer. A first metal bump member having a metal bump extending on the surface of the outer insulating layer from an inner wiring pattern inserted between the second inner insulating layer, a second outer insulating layer, A second metal having a second surface wiring pattern and a metal bump extending from the inner wiring pattern inserted between the second inner insulating layer and the outer insulating layer to the surface of the outer insulating layer; A bump member and an interlayer connection member for electrically connecting the wiring patterns separated by the insulating layer are provided.
[0010]
In the printed wiring board, an example of the interlayer wiring member is a paste bump.
[0011]
In the printed wiring board, examples of the interlayer wiring member include a through-hole metal layer.
[0012]
Still another printed wiring board of the present invention includes an insulating substrate, a first surface wiring pattern disposed on one surface of the insulating substrate, and a second surface covering the other surface of the insulating substrate. A wiring with metal bumps having a bottom part constituting a surface wiring pattern, a head part electrically connected to the first surface wiring pattern, and a bump part penetrating the insulating substrate from the bottom part to the head part And a member.
[0013]
The printed wiring board further includes a through-hole metal layer that is inserted in the thickness direction of the insulating substrate and electrically connects the first surface wiring pattern and the second surface wiring pattern. Also good.
[0014]
In the printed wiring board, an L / S value of the first surface wiring pattern and / or the second surface wiring pattern may be L / S = 10/10 to 40/40 (μm / μm).
[0015]
In the printed wiring board, the metal bumps may have a head radius of 20 to 100 μm, a bottom radius of 75 to 200 μm, and a height of 50 to 150 μm.
[0016]
Still another printed wiring board of the present invention is provided on an insulating substrate, a first surface wiring pattern disposed on one surface of the insulating substrate, and another surface of the insulating substrate. The second surface wiring pattern, the first surface wiring pattern or the metal bump electrically connected to the second surface wiring pattern, and the first surface wiring pattern and the second surface wiring A first metal bump-attached wiring member having an inner-layer wiring pattern disposed between and in parallel to the insulating substrate surface, and the second surface wiring pattern or the first surface. A metal bump electrically connected to the wiring pattern, and the first surface wiring pattern or the second surface wiring pattern and the first metal bump-attached wiring member, and the insulation Parallel to conductive substrate surface A wiring member with a second metal bump having another inner layer wiring pattern disposed; and at least the first wiring pattern and the second wiring pattern inserted in the thickness direction of the insulating substrate; And a through-hole plating layer for electrically connecting the two.
[0017]
In the printed wiring board, a core substrate in which an insulating layer and a wiring pattern are laminated may be interposed between the first wiring member with metal bumps and the second wiring member with metal bumps. .
[0018]
The printed wiring board manufacturing method of the present invention includes a step of masking the surface of a metal plate, and a bump in which a substantially conical metal bump is extended from the bottom surface of the metal plate by half-etching the metal plate through the masking. A step of forming an attached wiring member, a step of forming an insulating layer on a bump forming surface of the wiring member with bump, a step of polishing the surface of the insulating layer, and patterning a bottom surface of the bumped metal plate to form the insulation The method includes a step of forming one wiring pattern on the lower surface side of the layer and a step of forming another wiring pattern on the surface of the insulating layer.
[0019]
The method for manufacturing a printed wiring board further includes a step of forming a through-hole metal layer that electrically connects the one wiring pattern and the other wiring pattern after the other wiring pattern is formed. Also good.
[0020]
According to another method of manufacturing a printed wiring board of the present invention, a step of masking the surface of a metal plate, and a half-etching of the metal plate through the masking, a substantially conical metal bump is extended from the bottom surface of the metal plate. Patterning the bottom surface of the bumped metal plate, forming the bumped wiring member, forming the insulating layer on the bump forming surface of the bumped wiring member, polishing the insulating layer surface, A step of forming one wiring pattern on the lower surface side of the insulating layer, a step of forming another wiring pattern on the surface of the insulating layer to form two laminated plate units, and a core between the two laminated plate units. A step of forming an integrated laminate by pressing with an insulating layer interposed therebetween, and electrically connecting at least a wiring pattern on one surface of the laminate and a wiring pattern on the other surface of the laminate; And a step of forming a subsequent through-hole metal layer.
[0021]
In the method for manufacturing a printed wiring board, the core insulating layer may be a core board in which a wiring pattern and an insulating board are stacked.
[0022]
The printed wiring board of the present invention includes an insulating substrate, a first surface wiring pattern disposed on one surface of the insulating substrate, and a second surface disposed on the other surface of the insulating substrate. A surface wiring pattern, a metal bump electrically connected to the first surface wiring pattern or the second surface wiring pattern, and a wiring between the first surface wiring pattern and the second surface wiring pattern. A wiring member with metal bumps, and a wiring member with metal bumps formed of an inner layer wiring pattern disposed in parallel to the surface of the insulating substrate, the second surface wiring pattern, or the first surface wiring. And a paste bump electrically connected to the pattern.
[0023]
In the printed wiring board, as an example of the metal bump, a bump having a substantially conical shape with a pair of planes or curved surfaces that are parallel to the axis of the cone and with a skirt cut off can be cited. .
[0024]
In the printed wiring board, as an example of the metal bump, a bump having a shape formed by sequentially etching from the front surface side and the back surface side of the conductor plate can be exemplified.
[0025]
In the printed wiring board, the inner wiring pattern may be embedded in an insulating material layer constituting the insulating board through which the paste bump penetrates.
[0026]
The said printed wiring board can mention what the wiring member with a metal bump consists of the same continuous metal.
[0027]
In the printed wiring board, examples of the metal bumps include metal bumps having a head radius of 20 to 100 μm, a bottom radius of 75 to 200 μm, and a height of 50 to 150 μm.
[0028]
In the printed wiring board, examples of the surface wiring pattern include a pattern made of a metal foil processed into a pattern, a sputtered film, or a plated film.
[0029]
In the printed wiring board, examples of the metal bumps include a cylindrical shape, a conical shape, a quadrangular pyramid shape, a truncated cone shape, a truncated pyramid shape, and a group in which a cylindrical upper portion is joined to a lower portion of the conical shape. A bump having a shape approximating one selected shape can be mentioned.
[0030]
In the printed wiring board, as an example of the metal bump, a bump having a lower portion substantially equal to the width of the inner wiring pattern can be cited.
[0031]
In the printed wiring board, as an example of the metal bump, the longitudinal direction of the inner layer wiring pattern is a normal line having a substantially hexagonal shape including a pair of parallel planes facing each other and four curved surfaces connecting the parallel planes. And a bump having at least one of the curved surfaces having a negative radius of curvature.
[0032]
As the metal plate with a relief pattern for the printed wiring board of the present invention, a relief pattern corresponding to the inner layer wiring pattern of the wiring member with metal bumps is formed on one side of the metal material by half-etching one side of the metal material. The metal plate with the relief pattern for printed wiring boards currently formed can be mentioned.
[0033]
Another printed wiring board of the present invention includes a first surface wiring pattern disposed on one surface of the insulating substrate and a second surface wiring pattern disposed on the other surface of the insulating substrate. And metal bumps electrically connected to the first surface wiring pattern or the second surface wiring pattern, and disposed between the first surface wiring pattern and the second surface wiring pattern. And a first metal bump-attached wiring member having an inner layer wiring pattern disposed in parallel to the surface of the insulating substrate, and electrically connected to the second surface wiring pattern or the first surface wiring pattern. And disposed between the first surface wiring pattern or the second surface wiring pattern and the first metal bump-attached wiring member in parallel to the surface of the insulating substrate. Other inner layer wiring pads installed A first metal bump-attached wiring member, and a first metal bump-attached wiring member interposed between the first metal bump-attached wiring member and the second metal bump-attached wiring member. A paste bump for electrically connecting the member and the second wiring member with metal bump is provided.
[0034]
In the printed wiring board, as an example of the metal bump, a bump having a substantially conical shape with a pair of planes or curved surfaces that are parallel to the axis of the cone and with a skirt cut off can be cited. .
[0035]
In the printed wiring board, as an example of the metal bump, a bump having a shape formed by sequentially etching from the front surface side and the back surface side of the conductor plate can be exemplified.
[0036]
In the printed wiring board, the inner wiring pattern may be embedded in an insulating material layer that constitutes the insulating board and penetrates the paste bump.
[0037]
The said printed wiring board can mention what the wiring member with a metal bump consists of the same continuous metal.
[0038]
In the printed wiring board, examples of the metal bumps include metal bumps having a head radius of 20 to 100 μm, a bottom radius of 75 to 200 μm, and a height of 50 to 150 μm.
[0039]
In the printed wiring board, examples of the surface wiring pattern include a pattern made of a metal foil processed into a pattern, a sputtered film, a deposited film, or a plated film.
[0040]
In the printed wiring board, examples of the metal bumps include a cylindrical shape, a conical shape, a quadrangular pyramid shape, a truncated cone shape, a truncated pyramid shape, and a group formed by joining a cylindrical upper portion to a lower portion of the conical shape. A bump having a shape approximating one selected shape can be mentioned.
[0041]
In the printed wiring board, as an example of the metal bump, a bump having a lower portion substantially equal to the width of the inner wiring pattern can be exemplified.
[0042]
In the printed wiring board, as an example of the metal bump, a longitudinal direction of the inner layer wiring pattern of a substantially hexagonal shape including a pair of opposed parallel planes and four curved surfaces connecting the parallel planes. A bump having a planar cross-sectional shape as a normal line and at least one of the curved surfaces being a curved surface having a negative radius of curvature can be exemplified.
[0043]
As the metal plate with a relief pattern for the printed wiring board, a relief pattern corresponding to the inner layer wiring pattern of the wiring member with metal bumps is formed on one side of the metal material by half-etching one side of the metal material. A metal plate with a relief pattern for a printed wiring board can be mentioned.
[0044]
The method for producing a printed wiring board of the present invention includes a step of forming a first mask at an inner layer wiring pattern forming position on one surface of a conductor plate, and a half-etching of the mask forming surface of the conductor plate to form an inner layer wiring pattern. Forming a relief pattern on the one surface of the conductor plate, forming a paste bump at a predetermined position on the inner-layer wiring pattern-like relief pattern, an insulating material and another on the paste bump A step of aligning the conductor plate or the other wiring substrate, a step of pressing the conductor plate, the insulating material, the other conductor plate or the other wiring substrate under heating, and the other of the conductor plate. Forming a second mask at a metal bump forming position on the surface of the inner surface, and half-etching the other surface of the conductor plate to root the inner layer wiring pattern-like relief pattern Separating the portion into an inner layer wiring pattern and simultaneously forming a metal bump on the back surface of the inner layer wiring pattern, filling the metal bump forming surface with an insulating material, and curing the insulating material; Forming an outer wiring pattern on the exposed metal bump head and the insulating material layer.
[0045]
In the printed wiring board manufacturing method, an example of the insulating material is an insulating material that is an insulating substrate precursor.
[0046]
In the printed wiring board manufacturing method, an example of the insulating material is an insulating material composition film.
[0047]
In the method for manufacturing a printed wiring board, examples of the insulating material include an insulating material composition formed by coating.
[0048]
In the present invention, the conductive plate is half-etched to form a metal bump having the base portion bonded, and the first surface wiring pattern is formed by etching and cutting the base portion from the opposite side. It is possible to obtain a multilayer printed wiring board in which interlayer connections are made with metal bumps without raising the thickness.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a method for manufacturing a printed wiring board according to an embodiment of the present invention will be described. FIG. 1 is a flowchart showing the flow of each process of the printed wiring board manufacturing method according to the present embodiment, and FIGS. FIG.
[0050]
In order to manufacture the printed wiring board 1 according to this embodiment, a metal plate 11 such as a copper plate is first prepared as shown in FIG. Examples of the metal plate 11 include oxygen-free copper and a copper alloy. As the copper alloy, for example, an alloy containing 0.2% of a metal such as Cr or Sn can be used. The thickness of the metal plate 11 is selected according to the height and remaining thickness of metal bumps to be formed in a later process. For example, when a metal bump having a height of 140 μm is formed and a remaining thickness of 30 μm is required, the metal plate 11 having a thickness of 170 μm is used.
[0051]
Next, as shown in FIG. 2 (b), a first masking 20 is formed on the surface of the metal plate 11 on which half etching is performed, for example, on the upper surface side of the metal plate 11 in FIG. 2 (b). (Step 1). As a method of forming the first masking 20, first, a photosensitive resin is applied, dried, selectively exposed through a mask pattern, partially cured, and then developed to remove unnecessary portions. Examples include a photolithography method for dissolving and removing.
[0052]
On the other hand, a protective layer 21 is formed over the entire surface of the surface of the metal plate 11 on the surface not subjected to half-etching, that is, on the lower surface side in FIG. Thus, as shown in FIG. 2B, the first masking 20 is formed on the upper surface of the metal plate 11, and the protective layer 21 is formed on the lower surface of the metal plate 11.
[0053]
In this state, a half etching process is performed on the upper surface side of the metal plate 11 (step 2). As a method of this half etching treatment, a spray method in which an etching solution is sprayed, a wet method in which the metal plate 11 having the first masking 20 and the protective layer 21 formed therein is immersed in an etching solution tank, or an energy wave such as plasma. The dry method which makes a struck can be mentioned.
[0054]
Hereinafter, the spray method will be described as an example. When the etching solution is sprayed from the upper surface side of the metal plate 11 in the state shown in FIG. 2B, the spray solution sprayed in a mist form is an exposed surface between the first masking 20 and the first masking 20. The metal plate 11 is eroded, and further wraps around the lower surface side of the first masking 20 to etch the metal plate 11. Examples of the etchant used here include an etchant comprising a ferric chloride aqueous solution, a cupric chloride aqueous solution, and an alkaline aqueous solution mainly composed of a copper ammonium complex ion.
[0055]
When this etching process is stopped at an appropriate place (half etching / step 2), an inner layer wiring pattern having a cross-sectional shape (curved surface having a negative radius of curvature) drawn by a parabola or an elliptical curve as shown in FIG. Relief patterns 11B, 11B,... (Hereinafter referred to as “inner layer wiring relief pattern”) are obtained. These inner-layer wiring relief patterns 11B, 11B,... Are connected at their root portions 11A.
[0056]
Next, the first masking 20 and the protective layer 21 are removed (step 3), and the surface is washed to remove the etching solution. As a result, inner-layer wiring relief patterns 11B, 11B,... As shown in FIG. The provided metal plate with a wiring relief pattern (hereinafter referred to as “wiring member”) 11D is obtained.
[0057]
Next, a conductive paste obtained by dispersing conductive fine particles such as silver powder or copper powder in a liquid thermosetting resin such as epoxy resin is printed on the inner layer wiring relief patterns 11B, 11B,. The substantially conical paste bumps 12, 12,... Are formed using the method (step 4).
[0058]
Here, the “printing method” means, for example, that a metal mask having through holes formed at bump formation positions is overlaid on an insulating substrate on which a wiring pattern is formed, and the conductive paste is spatulated on the metal mask. In this method, an operation called “squeegee” is performed, and then the metal mask is peeled off to form a substantially conical minute paste bump on the wiring pattern. The paste bumps 12, 12,... Formed here are bumps having a bottom radius of 100 to 500 μm, a height of 70 to 550 μm, and a bottom radius to height aspect ratio of 1: 0.5 to 1: 3. The paste bumps 12, 12,... Are formed by drying after printing.
[0059]
After the formation of the paste bumps 12, 12,..., As shown in FIG. 3F, an insulating substrate precursor (prepreg) 13 is overlaid on the paste bumps 12, 12,. 5). The insulating substrate precursor (prepreg) 13 is, for example, a prepreg having a thickness of 60 μm, for example, formed by impregnating a glass cloth with an epoxy resin. This insulating substrate precursor (prepreg) 13 is overlaid on the surface of the wiring member 11D where the paste bumps 12 are formed (Step 5), and is pressed under heat in a state where the insulating substrate precursor (prepreg) is in contact with an elastic body such as a rubber sheet (Step 5). (Step 6).
[0060]
As a result of this heat press, an insulating substrate-attached wiring member 14 having paste bumps 12, 12,... Penetrated through an insulating substrate precursor (prepreg) 13 as shown in FIG. In this state, the inner layer wiring relief pattern 11B has a structure embedded in the layer of the prepreg 13 through which the paste bumps 12 penetrate.
[0061]
Next, another wiring member 21 obtained by performing the same operation as the above steps 1 to 3 is formed, and as shown in FIG. The member 21 is arranged so that the heads of the paste bumps 12, 12,... Face the wiring pattern forming surface having a convex cross section (step 7).
[0062]
Next, the insulating substrate-attached wiring member 14 and the other wiring member 21 that are arranged so as to face each other are heat-pressed (step 8). At this time, the heads of the paste bumps 12, 12,... And the inner layer wiring relief patterns 21B, 21B,... Of the other wiring members 21 come into contact with each other, and the inner layer wiring relief patterns 11B, 11B,. 21B,... Are electrically connected. At the same time, the insulating thermosetting resin in the prepreg 13 is cured and moves to the C stage.
[0063]
Thus, a so-called two-layer printed wiring board material 15 as shown in FIG. 3I is formed. Next, as shown in FIG. 4J, second masking 22 and 24 are formed on the metal bump forming portions of the wiring members 11D and 21 exposed on both surfaces of the printed wiring board material 15. (Step 9). Note that the second masking 22 and 24 can be formed by using a photolithography technique in the same manner as the first masking 20 is formed.
[0064]
After forming the second masking 22 and 24 as shown in FIG. 4 (j), etching is performed from above the second masking 22 and 24 to etch and separate the bottoms of the wiring members 11D and 21. , And metal bumps 11C, 11C,... And metal bumps 21C, 21C,... As shown in FIG. Thereby, the inner layer wiring relief patterns 11B and 21B of the wiring members 11D and 21 are simultaneously formed as inner layer wiring patterns 11E and 21E.
[0065]
FIG. 7 is a perspective view and a cross-sectional view of the metal bump obtained after the half etching process, and FIG. 8 is a joint portion between the inner layer wiring pattern and the metal bump formed by etching from the second masking 22 and 24 side. 9 is a cross-sectional photograph and an electron micrograph of the inner layer wiring relief pattern 11B obtained after the half etching process, and FIG. 10 is an inner layer formed by etching from the second masking 22 and 24 side. It is an electron micrograph of the joint part of a wiring pattern and a metal bump.
[0066]
As shown in FIG. 7 and FIG. 9, a substantially conical metal bump 11 </ b> C is formed by half-etching one surface of the metal plate 11. The cross section of the metal bump 11C has a shape in which the side surface of the truncated cone is replaced with a concave curved surface, in other words, a curved surface having a negative radius of curvature is provided on the side surface. As shown in FIGS. 7 and 9, the upper part of the metal bump 11C can be finished in a circular shape having a radius of about 20 to 100 μm, and the height of the metal bump 11C can be finished to about 50 to 150 μm. . In an actual product, the upper part of the metal bump 11C is preferably finished in a circle with a radius of about 40 to 75 μm, and the height of the metal bump 11C is preferably finished in a circle of about 70 to 120 μm.
[0067]
Also, as shown in FIGS. 8 and 10, by etching from the second masking side of step 10, the width of the skirt portion of the metal bump 11C is reduced to a line width substantially equal to the radius of the upper plane. At the same time, a strip-shaped wiring member with metal bump 11F in which the bottom of the metal bump 11C is coupled to the inner layer wiring pattern 11E is formed. In the wiring member 11F with metal bumps, the inner layer wiring pattern 11E is formed in a substantially planar shape, more precisely, a curved surface shape by etching from the second masking side in Step 9. FIG. 11 is a cross-sectional view showing the cross-sectional shape of the metal bump 11C as a cross-sectional shape when cut along a plane passing through the axis of the metal bump 11C with the longitudinal direction of the inner wiring pattern 11E of the wiring member 11F with the metal bump as a normal. It is. As shown in FIG. 11, the skirt portion of the metal bump 11C is eroded into a curved surface from the bottom surface side of the metal bump, that is, the second masking side, by the etching from the second masking side in Step 10, and is approximately hexagonal. The side surfaces defining a cross-sectional shape and defining a pair of parallel planes disposed at the top and bottom form a curved surface, and at least one of these four curved surfaces forms a curved surface having a negative radius of curvature. .
[0068]
At this time, the line width of the inner layer wiring pattern 11E of the wiring member 11F with metal bump formed on the bottom surface side of the metal bump 11C can be adjusted by the width of the second masking. The line width of the inner layer wiring pattern 11E of the wiring member 11F with a metal bump formed on the bottom surface side of the metal bump 11C can be about 30 μm at the minimum. In addition, in this wiring, the same wiring width can be formed in a portion where there is a bump on the back surface and a portion where there is no bump.
[0069]
After performing etching from the second masking side in this manner, the second masking 22 and 24 are then removed, whereby a two-layer printed wiring board material as shown in FIG. 19 is obtained.
[0070]
Next, as shown in FIG. 4 (m), the prepregs 26 and 28 are positioned on both the upper and lower surfaces of the printed wiring board material 19 and heat-pressed in the same manner as described above. As shown, a printed wiring board material 30 with an insulating material in which the metal bumps 11C and 21C penetrate the insulating material layers (prepreg) 26a and 28a is obtained (step 12). Next, the both surfaces of the resin-coated printed wiring board material 30 are polished by buffing or the like (step 13), so that the surface is flattened as shown in FIG. 5 (o). The material 32 for use is obtained.
[0071]
Next, a plating process such as electrolytic plating or electroless plating is performed on both surfaces of the resin-coated printed wiring board material 32 (step 14) to form the metal layer 31. Thereafter, third masks 34, 34,... Are formed on the metal layer 31 in the same manner as described above using, for example, a photolithography method (step 15), and the third masks 34, 34,. Then, an etching process is performed by supplying an etching solution (step 16), and the exposed portion of the metal layer 31 is removed, whereby a printed wiring board 40 as shown in FIG. 6 (r) is obtained. Next, when the masking 34, 34,... Adhering to the surface is removed (step 17), a printed wiring board 40 having a four-layer wiring pattern as shown in FIG.
[0072]
As described above, in the method for manufacturing a printed wiring board according to this embodiment, since the metal bumps 11C, 11C,... Formed by etching the metal plate 11 are used for interlayer connection, the metal bumps 11C, 11C,. Thus, interlayer connection with high connection reliability can be formed.
[0073]
In the printed wiring board according to the present embodiment, the metal plate 11 is etched from both the upper and lower sides to form the metal bump 11C and the inner layer wiring pattern 11E joined at the bottom thereof, so that the width of the metal bump 11C is the inner layer wiring pattern. It can be formed in a narrow width having the same dimensions as the width of 11E. Therefore, it is possible to reduce the distance between the adjacent metal bumps 11C and 11C, and it is possible to obtain a printed wiring board having a high wiring pattern density and thus a high degree of integration.
[0074]
Furthermore, in the printed wiring board according to the present embodiment, the metal plate 11 made of a single material is processed by half etching from the upper surface side and etching from the back surface side to form the metal bumps 11C, 11C,. Therefore, an inexpensive material can be used, and the product cost can be kept low.
[0075]
(Second Embodiment)
In the method for manufacturing a printed wiring board according to the present embodiment, in the first embodiment, an insulating substrate precursor (prepreg) is aligned, stacked, and heat-pressed to form an insulating material layer. Instead of penetrating the bump or metal bump through the insulating substrate precursor (prepreg), a method of applying a film made of an insulating material composition on the paste bump or metal bump was applied. The insulating material composition film coated on the paste bump or metal bump penetrates the paste bump or metal bump by pressure and heat, and its head protrudes above the insulating material composition film. In one embodiment, an insulating substrate precursor (prepreg) is stacked and heat-pressed to obtain the same state as paste bumps or metal bumps are passed through the insulating substrate precursor (prepreg).
[0076]
In this embodiment, since a method of coating an insulating material composition film is applied to form an insulating material layer on a paste bump or a metal bump, a large facility such as a flat plate high-pressure press is used. do not need.
[0077]
(Third embodiment)
In the method for manufacturing a printed wiring board according to the present embodiment, in the first embodiment, an insulating substrate precursor (prepreg) is aligned, stacked, and heat-pressed to form an insulating material layer. Instead of penetrating the bump or metal bump into the insulating substrate precursor (prepreg), a method of applying an insulating material composition on the paste bump or metal bump was adopted. By applying and forming an insulating material composition on a paste bump or metal bump so that its head is exposed, just in the first embodiment, an insulating substrate precursor (prepreg) is overlaid, and heat is applied. The same state as when the paste bumps and metal bumps are penetrated through the insulating substrate precursor (prepreg) by pressing is obtained.
[0078]
In this embodiment, a method of applying an insulating material composition to form a layer of an insulating material on a paste bump or a metal bump is adopted, so a large facility such as a flat plate high-pressure press is required. And not. In addition, since high-pressure pressing is not performed, there is little risk of deformation of bumps and the like, and a highly reliable interlayer connection can be formed.
[0079]
(Fourth embodiment)
Hereinafter, a method for manufacturing a printed wiring board according to an embodiment of the present invention will be described. FIG. 12 is a flowchart showing the flow of each process of the method for manufacturing a printed wiring board according to the present embodiment, and FIGS. 13 to 17 schematically illustrate the respective stages during the manufacturing of the printed wiring board according to the present embodiment. FIG.
[0080]
In order to manufacture the printed wiring board 1 according to the present embodiment, a metal plate 11 such as a copper plate is first prepared as shown in FIG. Examples of the metal plate 11 include Cu 99.9% oxygen-free copper having a plate thickness of about 150 μm.
[0081]
Next, as shown in FIG. 13B, a first masking 20 is formed on the surface of the metal plate 11 on the surface to which half etching is performed, for example, on the upper surface side of the metal plate 11 in FIG. (Step 1). As a method for forming the first masking 20, first, a photosensitive resin (photoresist) is applied, dried, and then emitted from, for example, a high-pressure mercury lamp with an output of 3 kW through a mask pattern on which a predetermined circuit pattern is drawn. The light is selectively exposed by irradiating parallel light and partially cured. Next, for example, 30 ° C., 1.0% sodium carbonate is sprayed on the surface at a pressure of 0.1 MPa to dissolve and remove the non-photosensitive surface, thereby developing and removing unnecessary portions.
[0082]
On the other hand, a protective layer 21 is formed over the entire surface of the surface of the metal plate 11 on the surface not subjected to half-etching, that is, on the lower surface side in FIG.
[0083]
In this state, a half etching process is performed on the upper surface side of the metal plate 11 (step 2).
[0084]
Hereinafter, the spray method will be described as an example. When the etching solution is sprayed from the upper surface side of the metal plate 11 in the state shown in FIG. 13B, the spray solution sprayed in a mist form is an exposed surface between the first masking 20 and the first masking 20. The metal plate 11 is eroded, and further wraps around the lower surface side of the first masking 20 to etch the metal plate 11. Examples of the half-etching method include a method of spraying a ferric chloride aqueous solution having a specific gravity of 1.4 at 50 ° C. at a pressure of 0.3 MPa and etching until the depth from the surface reaches 30 μm. .
[0085]
When this etching process is stopped at an appropriate point (half etching / step 2), the inner layer wiring relief having a cross-sectional shape (curved surface having a negative radius of curvature) drawn by a parabola or an elliptical curve as shown in FIG. 13C. Patterns 11B, 11B,... Are obtained. These inner-layer wiring relief patterns 11B, 11B,... Are connected at their root portions 11A.
[0086]
Next, the first masking 20 and the protective layer 21 are removed (step 3), and the surface is washed to remove the etching solution. As a result, inner-layer wiring relief patterns 11B, 11B,... As shown in FIG. The provided wiring member 11D is obtained.
[0087]
For removing the masking 20 and the protective layer, for example, a 3% sodium hydroxide aqueous solution at 50 ° C. is used.
[0088]
Next, a conductive paste obtained by dispersing conductive fine particles such as silver powder and copper powder in a liquid thermosetting resin such as an epoxy resin on the inner layer wiring relief patterns 11B, 11B,. For example, the substantially conical paste bumps 12, 12,... Are formed by using a so-called printing method in which a conductive paste is squeezed and squeezed from a metal mask having through holes of 0.3 mm diameter at predetermined bump formation positions. .
[0089]
After the formation of the paste bumps 12, 12,..., As shown in FIG. 14 (f), an insulating substrate precursor (prepreg), for example, an epoxy is applied to the glass cloth on the formation surface of the paste bumps 12, 12,. A prepreg 13 having a thickness of 60 μm, which is impregnated with resin, is overlaid (step 5).
[0090]
The prepreg 13 is overlaid on the surface of the wiring member 11D where the paste bumps 12 are formed (step 5), and is pressed (heat pressed) under heating in a state where it is in contact with an elastic body such as a rubber sheet (step 6). ).
[0091]
As a result of this heat press, an insulating substrate-attached wiring member 14 having paste bumps 12, 12,... Penetrated through the prepreg 13 as shown in FIG. In this state, the inner layer wiring relief pattern 11B has a structure embedded in the layer of the prepreg 13 through which the paste bumps 12 penetrate.
[0092]
Next, a conductor plate 51 such as a copper foil is prepared. As shown in FIG. 14 (h), the wiring member 14 with an insulating substrate and the conductor plate 51 are connected to the heads of the paste bumps 12, 12,. And the conductor plate 51 are arranged so as to face each other (step 7).
[0093]
Next, the resin-attached wiring member 14 and the conductor plate 51 that are arranged so as to face each other are heat-pressed (step 8). At this time, the heads of the paste bumps 12, 12,... And the conductor plate 51 come into contact with each other and are electrically connected. At the same time, the insulating thermosetting resin in the prepreg 13 is cured and moves to the C stage.
[0094]
Thus, a printed wiring board material 60 having a so-called two-layer structure as shown in FIG. 14I is formed. Next, in the wiring member 11D exposed on the surface of the printed wiring board material 60, second masking 22 and 53 are formed on the metal bump forming portion as shown in FIG. 15 (j) (step 9). ). The second masking 22 and 53 can be formed using a photolithography technique in the same manner as the first masking 20 is formed.
[0095]
After forming the second masking 22 and 53 as shown in FIG. 15 (j), the bottom of the wiring member 11D is etched and cut off from above the second masking 22 and 53, Metal bumps 11G, 11G,... As shown in FIG. 15 (k) are formed (step 10). Thereby, the inner layer wiring relief pattern 11B of the wiring member 11D is simultaneously formed as the inner layer wiring pattern 11H.
[0096]
After performing etching from the second masking side in this manner, the second masking 22 and 53 are then removed, whereby a two-layer printed wiring board material as shown in FIG. 62 is obtained.
[0097]
Next, the prepreg 26 having a thickness of 60 μm, for example, is positioned on the upper surface of the printed wiring board material 62 and heat-pressed by the same method as described above, whereby an insulating material layer (as shown in FIG. A printed wiring board material 63 with an insulating material, in which the head portion 11C of the metal bump 11G penetrates the prepreg 26a, is obtained (step 12).
[0098]
Next, by polishing the upper surface of the printed wiring board material 63 with insulating material by buffing or the like (step 13), the printed wiring with insulating material whose surface is flattened as shown in FIG. A substrate material 64 is obtained.
[0099]
Next, a plating process such as electrolytic plating or electroless plating is performed on both surfaces of the printed wiring board material 64 with insulating material (step 14) to form the metal layer 31. For example, after the surface is first immersed in 1% sulfuric acid, the surface is washed with water. Thereafter, the palladium-tin complex is adsorbed on the surface, and then the tin component is removed. Subsequently, about 0.3 μm of copper is precipitated in a mixed solution of formalin, sodium hydroxide and copper sulfate. Then, further electrolytic plating is performed. For example, 3 A / dm in a mixed solution of sulfuric acid and copper sulfate at 30 ° C. ² Is applied for about 10 minutes to deposit 5 μm of copper on the surface.
[0100]
Thereafter, third masks 34, 34,..., 55, 55,... And 55, 55,... Are formed on the metal layer 31 in the same manner as described above by using, for example, photolithography (step 15). When an etching solution is supplied from above 34, 34,..., 55, 55,... (Step 16) and the exposed portions of the metal layers 31, 51 are removed, FIG. A printed wiring board 66 as shown is obtained. .. And 55, 55,... Adhering to the surface are then removed (step 17) to obtain a printed wiring board 66 having a three-layer wiring pattern as shown in FIG. .
[0101]
As described above, in the method for manufacturing a printed wiring board according to the present embodiment, since the metal bumps 11G, 11G,... Formed by etching the metal plate 11 are used for interlayer connection, the metal bumps 11G, 11G,. It is possible to form an interlayer connection with a small connection height and a high connection reliability.
[0102]
In the printed wiring board according to the present embodiment, the metal plate 11 is etched from the upper and lower surfaces to form the metal bump 11G and the inner layer wiring pattern 11H joined at the bottom thereof, so that the width of the metal bump 11G is the inner layer wiring pattern. It can be formed in a narrow width having the same dimensions as the width of 11H. Therefore, the interval between the adjacent metal bumps 11G and 11G can be reduced, and a printed wiring board having a high wiring pattern density and, consequently, a high degree of integration can be obtained.
[0103]
Furthermore, in the printed wiring board according to the present embodiment, the metal plate 11 made of a single material is processed by half etching from the upper surface side and etching from the back surface side to form the metal bumps 11G, 11G,. Therefore, an inexpensive material can be used, and the product cost can be kept low.
[0104]
(Example 1)
Examples of the present invention will be described below. In this embodiment, a photosensitive resist is applied to both sides of a copper plate having a thickness of 150 microns made of oxygen-free copper of Cu 99.9% or more, and a film mask in which a predetermined wiring pattern pattern is drawn in advance on one side is used. Vacuum contact exposure was performed using parallel light emitted from a 3 kW ultrahigh pressure mercury lamp from above. Next, the pattern baked by exposure was developed. For development, 1.0% sodium carbonate at 30 ° C. was sprayed onto the surface at a pressure of 0.1 MPa to dissolve and remove the non-photosensitive surface.
[0105]
The copper plate surface exposed by development was etched to form a wiring member by half-etching a predetermined inner layer wiring relief pattern. As a half-etching method, an aqueous ferric chloride solution having a specific gravity of 1.4 at 50 ° C. was sprayed at a pressure of 0.3 MPa, and etching was performed until the depth reached about 30 μm. Next, the photosensitive resist was peeled off, washed and dried.
[0106]
Next, using a metal mask having a 0.2 mm diameter hole drilled at a predetermined position of a stainless steel plate having a thickness of 0.2 mm, a projection (bump) of an epoxy resin silver paste is printed at a predetermined position of the wiring member, It was made to dry and the paste bump was formed. Such screen printing and drying steps were repeated a plurality of times to form paste bumps having a predetermined height.
[0107]
Next, a prepreg having a thickness of 60 μm formed by impregnating and applying an epoxy resin to a glass cloth is laminated on the wiring member on which the bumps are printed, and is passed between heat rollers so that the tips of the bumps are placed on the prepreg. The laminated body which penetrated was obtained.
[0108]
A wiring member with another wiring relief pattern in which a pattern of a predetermined wiring pattern was formed on one side by performing the same process as the half etching described above was created. With respect to the other wiring member with the wiring relief pattern, the laminated body is turned upside down, and the two wiring members are stacked so that the respective wiring relief pattern faces each other, a heating mechanism, a pressure mechanism, and Then, it was set in a press apparatus equipped with a cooling mechanism and pressed at 175 ° C. and 3 MPa for 60 minutes to prepare a double-sided copper-clad printed wiring board material provided with a through-type conductor.
[0109]
Parallel light emitted from a 3 kW ultrahigh pressure mercury lamp using a film mask in which a photosensitive resist is applied on both sides of the printed wiring board material and a pattern of a predetermined conductive bump (metal bump) is drawn in advance. Were subjected to vacuum contact exposure. After the exposure, 1.0% sodium carbonate was sprayed onto both surfaces of the printed wiring board material coated with the photosensitive resist under the conditions of 30 ° C. and a pressure of 0.1 MPa to dissolve and remove the non-photosensitive surface. . The copper plate surfaces on both sides of the printed wiring board material exposed by the development were etched to form predetermined metal bumps by half etching. In this half-etching process, a ferric chloride aqueous solution having a specific gravity of 1.4 at 50 ° C. was sprayed at a pressure of 0.3 MPa, and half-etching was performed until a predetermined thickness was achieved. Next, the photosensitive resist was peeled off, washed, and dried. For peeling, an aqueous solution of sodium hydroxide at 50 ° C. and 3% was used.
[0110]
Next, a prepreg having a thickness of 60 μm formed by impregnating and applying an epoxy resin to a glass cloth is laminated on the upper and lower surfaces of the printed wiring board material on which the metal bumps are formed, and is passed between heat rollers, The laminated body which the front-end | tip of the metal bump of the front and back penetrated the said prepreg, respectively was formed. Polishing was performed by bringing a polishing roll or the like into contact with both surfaces of the laminate thus obtained, and the surface condition was adjusted so that the surface of the prepreg and the tip surface of the metal bumps were coplanar.
[0111]
Next, both surfaces of the surface polished laminate were plated to form a copper layer. In this step, first, electroless plating was performed to form a thin plating layer on the surface of the laminate. Specifically, first, the surface of the laminate was immersed in 1% sulfuric acid, and then the surface was washed with water. Thereafter, a palladium-tin complex was adsorbed on the surface, and then the tin component was removed. Thereafter, copper was deposited to a thickness of about 0.3 μm in a mixed solution of formalin, sodium hydroxide and copper sulfate. Next, electrolytic plating was performed on the copper layer. Specifically, in a mixed solution of sulfuric acid and copper sulfate at 30 ° C., 3 A / dm ² Was applied for about 10 minutes to form a copper layer having a thickness of 5 μm on the surface. A photo resist is applied on the surface of the copper layer, a film mask on which a pattern of a predetermined surface wiring pattern is drawn in advance is superimposed, and parallel light emitted from a 3 kW ultra-high pressure mercury lamp is irradiated from above the film mask. Vacuum contact exposure was performed. The pattern thus baked was developed. Development was performed by spraying 1.0% sodium carbonate on the surface under conditions of 30 ° C. and a pressure of 0.1 MPa to dissolve and remove the non-photosensitive surface.
[0112]
The copper layer surface exposed by the development was etched to form a predetermined wiring pattern by half etching. Specifically, a ferric chloride aqueous solution having a specific gravity of 1.4 at 50 ° C. was sprayed and sprayed at a pressure of 0.3 MPa, and half-etched until a predetermined thickness was achieved. Next, the photosensitive resist was peeled off, washed and dried. For peeling, an aqueous solution of sodium hydroxide at 50 ° C. and 3% was used.
[0113]
The printed wiring board thus obtained was confirmed to be a high-quality printed wiring board having the following excellent characteristics. In the outermost layer, it was not necessary to form lands in the interlayer connection portion, and a high-definition printed wiring board with L / S = 40/40 μm was obtained. Furthermore, when a hot oil test was performed on the printed circuit board, high reliability within a resistance change rate of 10% was confirmed after 500 cycles.
[0114]
(Example 2)
Examples of the present invention will be described below. In this example, in the same manner as in the first embodiment, the wiring member on which the paste bump is formed and another wiring member are brought into contact with each other to make an interlayer connection, and both surfaces of the formed printed wiring board material are again formed. Etching was used to form metal bumps. As the next step, a film-like insulating material containing epoxy resin as a main component and having photosensitivity was prepared instead of heat-pressing a prepreg layered on a metal bump. After laminating the insulating material on the upper and lower sides of the wiring member, the front and back films were irradiated with ultraviolet rays to cure the resin in the photosensitive film-like insulating material. Subsequent operations were the same as those in the first example.
[0115]
The printed wiring board thus obtained was confirmed to be a high-quality printed wiring board having the following excellent characteristics.
[0116]
That is, in the outermost layer, it is not necessary to form a land in the interlayer connection portion, and a high-definition printed wiring board with L / S = 40/40 μm was obtained. Furthermore, when a hot oil test was performed on the printed wiring board, high reliability within a resistance value change rate of 10% or less was confirmed after 500 cycles.
[0117]
(Example 3)
Examples of the present invention will be described below. In this example, in the same manner as in the first embodiment, the wiring member on which the paste bump is formed and another wiring member are brought into contact with each other to make an interlayer connection, and both surfaces of the formed printed wiring board material are again formed. Etching was used to form metal bumps. As the next step, an insulating liquid resin was applied by a curtain coat and dried, instead of heat-pressing the prepreg on the metal bump. Subsequent operations were the same as those in the first example.
[0118]
The printed wiring board thus obtained was confirmed to be a high-quality printed wiring board having the following excellent characteristics.
[0119]
That is, in the outermost layer, it is not necessary to form a land in the interlayer connection portion, and a high-definition printed wiring board with L / S = 40/40 μm was obtained. Furthermore, when a hot oil test was performed on the printed wiring board, high reliability within a resistance value change rate of 10% or less was confirmed after 500 cycles.
[0120]
(Fifth embodiment)
In the present embodiment, the first wiring pattern is formed on one surface of the insulating substrate, and the second wiring pattern with metal bumps is formed on the other surface. The first wiring pattern and the second wiring pattern are electrically connected via metal bumps formed integrally with the second wiring pattern. FIG. 18 is a flowchart of a method for manufacturing a printed wiring board according to the present embodiment, and FIGS. 19 and 20 are cross-sectional views schematically showing each stage in the process of manufacturing the printed wiring board according to the present embodiment. It is.
[0121]
In order to manufacture the printed wiring board 1 according to this embodiment, a metal plate 11 such as a copper plate is first prepared as shown in FIG. Next, as shown in FIG. 19B, a first masking 41 is formed on the surface of the metal plate 11 on the surface to be half-etched, for example, on the upper surface side of the metal plate 11 in FIG. (Step 1).
[0122]
On the other hand, the protective layer 43 is formed over the entire surface of the surface of the metal plate 11 on the surface not subjected to half-etching, that is, on the lower surface side in FIG. Thus, as shown in FIG. 19B, the first masking 41 is formed on the upper surface of the metal plate 11, and the protective layer 43 is formed on the lower surface of the metal plate 11. In this state, a half etching process is performed on the upper surface side of the metal plate 11 (step 2). When the etching solution is sprayed from the upper surface side of the metal plate 11 in the state shown in FIG. 19B, the sprayed spray solution is exposed on the surface between the first masking 41 and the first masking 41. The metal plate 11 is eroded, and the metal plate 11 is etched by going around to the lower surface side of the first masking 41.
[0123]
When this etching process is stopped at an appropriate point (half etching / step 2), a metal bump 11B having a cross-sectional shape (curved surface having a negative radius of curvature) drawn by a parabola or an elliptic curve as shown in FIG. 19C. , 11B,... These metal bumps 11B, 11B,... Are connected at the base portion 11A. Next, the first masking 41 and the protective layer 43 are removed (step 3), and the surface is washed to remove the etching solution. As a result, a metal plate with a wiring relief pattern (hereinafter referred to as “wiring member”) 11C provided with metal bumps 11B, 11B,... As shown in FIG.
[0124]
Next, an insulating material layer (insulating layer) 13 as shown in FIG. 19E is formed on the metal bump forming surface of the wiring member 11C (step 4). Examples of the method for forming the insulating material layer 13 include a method in which a prepreg is stacked and pressed, a method in which a liquid insulating material composition is applied, a method in which a film made of an insulating material is stacked and the metal bumps 11B are penetrated. Next, the surface of the insulating material layer 13 is polished and the metal bumps 11B protruding from the surface of the insulating material layer 13 are shaved (step 5), and the surface is smoothed as shown in FIG. Next, the smoothed surface is plated (step 6) to form a metal layer 45 as shown in FIG. Next, as shown in FIG. 20 (h), second masks 47 and 48 are formed on both surfaces of the two-layer plate 49 (step 7). Next, as shown in FIG. 20I, the second masking 47, 48 is patterned by, for example, photolithography. Thereafter, etching is performed on the second masking 47 and 48 to pattern the metal layers 45 and 11A (step 8). As a result, the excess metal portion is removed as shown in FIG. Next, when the second masking 47a and 48a are removed (step 9), a double-sided wiring board 49a as shown in FIG. 20 (k) is obtained.
[0125]
In the double-sided wiring board according to the present embodiment, interlayer connection is formed through metal bumps formed integrally with the wiring pattern. Therefore, highly reliable interlayer connection can be obtained. Further, since a through hole such as a through hole is not formed, a printed wiring board having a high degree of integration can be obtained.
[0126]
(Sixth embodiment)
In the present embodiment, a multilayer board is formed by using both metal bumps formed by etching and through-hole plating. FIG. 21 is a flowchart of a method for manufacturing a printed wiring board according to the present embodiment, and FIGS. 22 to 25 are cross-sectional views schematically showing each stage in the process of manufacturing the printed wiring board according to the present embodiment. is there.
[0127]
In order to manufacture the printed wiring board 1 according to this embodiment, a metal plate 11 such as a copper plate is prepared as shown in FIG. Next, as shown in FIG. 22 (b), the first masking 41 is provided on the surface of the metal plate 11 on which half etching is performed, for example, on the upper surface side of the metal plate 11 in FIG. 22 (b). Form (step 1).
[0128]
On the other hand, a protective layer 43 is formed over the entire surface of the surface of the metal plate 11 on the surface not subjected to half-etching, that is, on the lower surface side in FIG. Thus, as shown in FIG. 22B, the first masking 41 is formed on the upper surface of the metal plate 11, and the protective layer 43 is formed on the lower surface of the metal plate 11. In this state, a half etching process is performed on the upper surface side of the metal plate 11 (step 2). When the etching solution is sprayed from the upper surface side of the metal plate 11 in the state shown in FIG. 22B, the spray solution sprayed in a mist form is an exposed surface between the first masking 41 and the first masking 41. The metal plate 11 is eroded, and the metal plate 11 is etched by going around to the lower surface side of the first masking 41.
[0129]
When this etching process is stopped at an appropriate point (half etching / step 2), a metal bump 11B having a cross-sectional shape (curved surface having a negative radius of curvature) drawn by a parabola or an elliptic curve as shown in FIG. , 11B,... These metal bumps 11B, 11B,... Are connected at the base portion 11A. Next, the first masking 41 and the protective layer 43 are removed (step 3), and the surface is washed to remove the etching solution. As a result, a metal plate with a wiring relief pattern (hereinafter referred to as “wiring member”) 11C provided with metal bumps 11B, 11B,... As shown in FIG.
[0130]
Next, an insulating material layer (insulating layer) 13 as shown in FIG. 22E is formed on the metal bump forming surface of the wiring member 11C (step 4). Next, as shown in FIG. 23F, a second masking layer 46 made of a photoresist is formed on the lower surface of the wiring member 11C (step 5). The second masking layer 46 is patterned by a photolithography method and patterned as shown in FIG. 23G to form a second masking 46a. Next, etching is performed from above the second masking 46a (step 6). As a result, the metal layer 11A at the bottom of the wiring member is patterned as shown in FIG. When the second masking 46a on the metal layer 11A is removed (step 7), a multilayer plate unit 71a as shown in FIG. 23 (i) is obtained. On the other hand, another multilayer board unit 73a is prepared in the same manner as this multilayer board unit.
[0131]
Next, a set of two multilayer board units 71a and 73a formed as described above are overlapped with each other facing each other with the prepreg 72 interposed therebetween as shown in FIG. 23 (j) (step 8). Heat press is performed in this superposed state (step 9). As a result, a multilayer board intermediate body 75 as shown in FIG. 24 (k) is obtained. Since the tips of the heads of the metal bumps 11B and 11J protrude from the surface of the multilayer board intermediate body 75 as shown in FIG. 24 (k), the surface of the multilayer board intermediate body 75 is polished (step 10). As a result, the surface of the multilayer board intermediate body 75 is smoothed as shown in FIG. Next, a through hole 67 is formed at a predetermined position of the multilayer board intermediate body 75 by mechanical processing such as drilling or optical processing such as laser light irradiation (step 11). As a result, a multilayer board intermediate body 75a having through holes 67 for through holes as shown in FIG. 24 (m) is formed. Next, through-hole plating is performed on the surface of the multilayer board intermediate body 75a (step 12). As a result, a through-hole plating layer 68 as shown in FIG. 24 (n) is formed. Next, the metal layer 68 on the surface of the multilayer plate intermediate body 75b is patterned by selective etching or the like (step 13). As a result, a multilayer board 77 as shown in FIG.
[0132]
In this embodiment, metal bumps and through-hole plating are used together to form an interlayer connection. Therefore, it is possible to obtain a multilayer board in which a highly reliable interlayer connection is formed.
[0133]
(Seventh embodiment)
In the present embodiment, a multilayer board is formed by using both metal bumps formed by etching and through-hole plating. FIG. 26 is a flowchart of a method for manufacturing a printed wiring board according to the present embodiment, and FIGS. 27 to 31 are cross-sectional views schematically showing each stage in the process of manufacturing the printed wiring board according to the present embodiment. is there.
[0134]
In order to manufacture the printed wiring board according to the present embodiment, a metal plate 10 such as a copper plate is prepared as shown in FIG. Next, as shown in FIG. 27 (b), of the surface of the metal plate 10, the surface on which the half wiring process is performed to form the inner wiring pattern, for example, the lower surface of the metal plate 10 in FIG. 27 (b). A first masking is formed on the side (step 1).
[0135]
On the other hand, a protective layer 42 is formed over the entire surface of the surface of the metal plate 10 on the surface on which the inner wiring pattern is not formed, that is, on the upper surface side in FIG. Thus, as shown in FIG. 27B, the first masking 46 is formed on the lower surface of the metal plate 10, and the protective layer 42 is formed on the upper surface of the metal plate 10. In this state, a half etching process is performed on the lower surface side of the metal plate 10 (step 2). When the etching solution is sprayed from the upper surface side of the metal plate 10 in the state shown in FIG. 27B, the etching solution sprayed in a mist form is an exposed surface between the first masking 44 and the first masking 44. The metal plate 10 is eroded and etched into a shape corresponding to the pattern of the first masking 44.
[0136]
When this etching process is stopped at an appropriate point (half etching / step 2), an inner wiring pattern 46 is formed on the lower surface of the metal plate 10 as shown in FIG. The first masking 44 and the protective layer 42 are removed from the surface of the metal plate 10 on which the inner wiring pattern 46 is formed on the lower surface side (step 3). Then, the metal plate 10 as shown in FIG. 27 (d) is formed. Another metal plate 10a is formed in the same manner as described above. Next, as shown in FIG. 27E, a core material 29 having a four-layer wiring pattern 27 is prepared. Two prepregs 26 and 28 and two metal plates 10 and 10a are arranged opposite to each other on both surfaces of the core material 27 so as to overlap each other (step 4). Heat pressing is performed in this state (step 5). As a result, a multilayer board intermediate 80 as shown in FIG. 28 (f) is obtained.
[0137]
Next, as shown in FIG. 28G, second masks 47 and 48 are formed at predetermined positions on both surfaces of the multilayer board intermediate 80, more precisely at positions where metal bumps are to be formed (step 6). In this state, half-etching is performed on both surfaces of the multilayer board intermediate 80 (step 7). When the etching solution is sprayed from both surfaces of the multilayer board intermediate body 80 in the state shown in FIG. 29 (h), the etching solution sprayed in the form of mist forms the second masking 47 (48) and the second masking 47 (48). The metal plates 10 and 10a on the exposed surface between them are eroded, and the metal plates 10 and 10a are etched by going to the lower surface side of the second masking 47 and 48.
[0138]
When this etching process is stopped at an appropriate point (half etching / step 7), a metal bump 11B having a cross-sectional shape (curved surface having a negative radius of curvature) drawn by a parabola or an elliptic curve as shown in FIG. , 11B,... The metal plates 10 and 10a are shaved from the surface side by the half etching and become thin. Finally, the inner wiring patterns 46 and 46a formed on the bottom surface side of the metal plates 10 and 10a are cut off to complete the inner wiring patterns 46 and 46a.
[0139]
Next, the second masking 47 and 48 are removed (step 8), and the surface is washed to remove the etching solution. As a result, a multilayer plate intermediate 80a having metal bumps 11B, 11B,... As shown in FIG.
[0140]
Next, insulating material layers (insulating layers) 13a and 13b as shown in FIG. 30 (j) are formed on the metal bump forming surface of the multilayer plate intermediate 80a (step 9). Thereafter, the surface is polished (step 10), and the surface of the multilayer board intermediate 80c is smoothed as shown in FIG. 30 (k) (step 10).
[0141]
Next, as shown in FIG. 31 (l), a through hole 67 is formed by applying mechanical processing to a predetermined position of the multilayer board intermediate 80c, that is, a through hole forming position (step 11). Next, the surface of the multilayer plate intermediate body 80d is plated by electroless plating or electrolytic plating (step 12). As a result, a through-hole plating layer 68 as shown in FIG. 31 (m) is formed. Next, the metal layer 68 on the surface of the multilayer plate intermediate body 80e is patterned (step 13). Thus, a multilayer board 82 in which the metal bumps 11B and 11J and the through-hole plating 68 are mixed as shown in FIG.
[0142]
In this embodiment, metal bumps and through-hole plating are used together to form an interlayer connection. Therefore, it is possible to obtain a multilayer board in which a highly reliable interlayer connection is formed.
[0143]
(Eighth embodiment)
The printed wiring board according to the present embodiment has a configuration in which Ni / Au plating is further performed on the metal layer on the surface of the printed wiring board formed in the fourth embodiment. FIG. 32 is a partially enlarged view of a cross-sectional view of the printed wiring board according to the present embodiment. FIG. 33 is a sectional view showing a final usage pattern of the printed wiring board according to the present embodiment. As shown in FIG. 32, in the printed wiring board according to the present embodiment, Ni / Au plating is further formed on the surface metal layer.
[0144]
In order to manufacture the printed wiring board according to the present embodiment, the manufacturing method of the fourth embodiment is generally followed. That is, the insulating substrate material 63 as shown in FIG. 32 (n) is formed according to Steps 1 to 13 of the fourth embodiment. Next, the upper surface of the insulating substrate material 63 is polished and smoothed to form an insulating substrate material 64 as shown in FIG. The metal layer 51 on the lower surface side of the insulating substrate material 64 is patterned by selective etching or the like to form an insulating substrate material 65 as shown in FIG. Next, both surfaces of the insulating substrate material 65 are plated to form Ni / Au plated layers 56 and 57. Thus, a printed wiring board 67 as shown in FIG. 32 (q) is formed.
[0145]
As an application of the printed wiring board according to the present embodiment, there is an application as a contact sheet 90 of a semiconductor device as shown in FIG. The contact sheet is a sheet that is interposed between the semiconductor device 83 and the circuit board 86 of the semiconductor device test apparatus to electrically connect the electrode 84 of the semiconductor device 83 and the electrode 87 of the circuit board. FIG. 33A is a schematic configuration of a test apparatus for conducting a continuity test of the semiconductor device 83. In this test apparatus, a circuit board 86 is fixed on a fixing base 88, and a contact sheet 90 is positioned and fixed thereon with positioning pins 97. The semiconductor device 83 is placed on the contact sheet 90 and pressed by the pressing tool 85.
[0146]
FIG. 33 (b) is an enlarged view of the small circle part of FIG. 33 (a). As shown in FIG. 33B, in the contact sheet 90 according to this embodiment, metal bumps 92 are embedded in the thickness direction of the insulating layer 91. Terminals 93 and 94 are disposed on the surface of the insulating layer 91, respectively. The metal layers on the surfaces of the terminals 93 and 94 are formed by Ni / Au plating. The metal bumps 92 and the terminals 94 are electrically connected via silver paste bumps 96. Further, since the interlayer connection is formed by the etching bump in the printed wiring board according to the present embodiment, a sheet having a small electric resistance and a uniform thickness can be produced. Further, since the contact sheet 90 according to the present embodiment has such a structure, the contact sheet 90 is used by being inserted between the object to be inspected and the test apparatus to absorb the stress applied to the object to be inspected. Can be pressed against the test device and sufficient electrical contact is obtained.
[0147]
【The invention's effect】
According to the present invention, since the metal bumps are formed by sequentially etching the metal plate from the front and back surfaces, a printed wiring board having higher height uniformity and therefore high reliability of interlayer connection can be obtained. Further, since the metal bumps are formed by sequentially etching from the front and back of the metal plate, a metal plate made of a single material can be used, and the manufacturing cost can be kept low. Further, by etching from the base side of the metal bump formed by half etching, the skirt portion of the metal bump is killed, and a printed wiring board having high wiring density and high reliability can be obtained.
[Brief description of the drawings]
FIG. 1 is a flowchart showing each step of a printed wiring board manufacturing method according to a first embodiment.
FIG. 2 is a cross-sectional view showing each step of the printed wiring board manufacturing method according to the first embodiment.
FIG. 3 is a cross-sectional view showing each step of the printed wiring board manufacturing method according to the first embodiment.
FIG. 4 is a cross-sectional view showing each step of the printed wiring board manufacturing method according to the first embodiment.
FIG. 5 is a cross-sectional view showing each step of the printed wiring board manufacturing method according to the first embodiment.
FIG. 6 is a cross-sectional view showing each step of the printed wiring board manufacturing method according to the first embodiment.
FIG. 7 is a schematic view of a wiring member with metal bumps according to the first embodiment.
FIG. 8 is a schematic view of a wiring member with metal bumps according to the first embodiment.
FIG. 9 is an electron micrograph of a wiring member with metal bumps according to the first embodiment.
FIG. 10 is an electron micrograph of a wiring member with metal bumps according to the first embodiment.
FIG. 11 is a cross-sectional view of a metal bump taken along a plane passing through the axis of the metal bump with the longitudinal direction of the wiring member with the metal bump as a normal line.
FIG. 12 is a flowchart showing each step of a printed wiring board manufacturing method according to the fourth embodiment.
FIG. 13 is a cross-sectional view showing each step of a printed wiring board manufacturing method according to the fourth embodiment.
FIG. 14 is a cross-sectional view showing each step of a printed wiring board manufacturing method according to the fourth embodiment.
FIG. 15 is a sectional view showing each step of a printed wiring board manufacturing method according to the fourth embodiment.
FIG. 16 is a cross-sectional view illustrating each step of a printed wiring board manufacturing method according to the fourth embodiment.
FIG. 17 is a cross-sectional view showing each step of a printed wiring board manufacturing method according to the fourth embodiment.
FIG. 18 is a flowchart of a method for manufacturing a printed wiring board according to a fifth embodiment.
FIG. 19 is a cross-sectional view of the printed wiring board according to the fifth embodiment in the middle of manufacture.
FIG. 20 is a cross-sectional view of the printed wiring board according to the fifth embodiment in the middle of manufacture.
FIG. 21 is a flowchart of a method for manufacturing a printed wiring board according to a sixth embodiment.
FIG. 22 is a cross-sectional view of the printed wiring board according to the sixth embodiment in the middle of manufacture.
FIG. 23 is a cross-sectional view of the printed wiring board according to the sixth embodiment in the middle of manufacture.
FIG. 24 is a cross-sectional view of the printed wiring board according to the sixth embodiment in the middle of manufacture.
FIG. 25 is a cross-sectional view of the printed wiring board according to the sixth embodiment in the middle of manufacture.
FIG. 26 is a flowchart of a method for manufacturing a printed wiring board according to a seventh embodiment.
FIG. 27 is a flowchart of a method for manufacturing a printed wiring board according to a seventh embodiment.
FIG. 28 is a flowchart of a method for manufacturing a printed wiring board according to a seventh embodiment.
FIG. 29 is a flowchart of a method for manufacturing a printed wiring board according to a seventh embodiment.
FIG. 30 is a flowchart of a method for manufacturing a printed wiring board according to a seventh embodiment.
FIG. 31 is a flowchart of a method for manufacturing a printed wiring board according to a seventh embodiment.
FIG. 32 is a partially enlarged view of a cross-sectional view of a printed wiring board according to an eighth embodiment.
FIG. 33 is a cross-sectional view showing a usage pattern of a printed wiring board according to an eighth embodiment.
FIG. 34 is a cross-sectional view showing a manufacturing process of a conventional conductor penetration method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Metal plate, 11B ... Inner layer wiring relief pattern, 11C ... Metal bump, 11D ... Wiring member, 11E ... Inner layer wiring pattern, 11F ... Wiring member with metal bump, 13 ... Pre-preg (insulating substrate), 20 ... First Masking, 31a ... first surface wiring pattern, 32a ... second surface wiring pattern, 41 ... second masking.

Claims (4)

Forming a first masking at an inner wiring pattern forming position on one surface of the conductor plate;
Forming a relief pattern on the one surface of the conductor plate by half-etching the masking formation surface of the conductor plate to form an inner layer wiring pattern; and
Forming paste bumps at predetermined positions on the inner wiring pattern-like relief pattern;
A step of aligning an insulating material and another conductor plate or another wiring board on the paste bump;
Pressurizing the conductive plate, the insulating material, another conductive plate or another wiring board under heating;
Forming a second mask at a metal bump formation position on the other surface of the conductor plate;
Forming a metal bump on the back of the inner layer wiring pattern at the same time as half-etching the other surface of the conductor plate to separate the root portion of the inner layer wiring pattern-like relief pattern into an inner layer wiring pattern;
Filling the metal bump formation surface with an insulating material;
Curing the insulating material;
And a step of forming an outer wiring pattern on the exposed metal bump head and the insulating material layer. The method for manufacturing a printed wiring board according to claim 1 , wherein the insulating material is an insulating substrate precursor. The method for manufacturing a printed wiring board according to claim 1 , wherein the insulating material is an insulating material composition film. The method for manufacturing a printed wiring board according to claim 1 , wherein the insulating material is an insulating material composition formed by coating.

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