JP4299087B2 - Printed wiring board - Google Patents

Description

  The present invention relates to a printed wiring board, and more particularly to a printed wiring board on which a plurality of pads to which protruding electrode terminals arranged in a grid pattern such as a ball grid array (BGA) are welded are formed.

  Conventionally, various electronic component mounting methods have been proposed as electronic components are highly integrated. Among these, a module (hereinafter referred to as “BGA module”) technology that employs an array of ball electrodes for external connection referred to as a ball grid array or land grid array (LGA) (hereinafter simply referred to as “ball grid array”). Is attracting attention.

  In a BGA module, a semiconductor element (semiconductor chip) is mounted on the surface of a printed wiring board (hereinafter also referred to as a “BGA module substrate”), also called an interposer substrate, and ball electrodes for external connection are arranged on the back surface of the module substrate. It is supposed to be. For this reason, there is no need to project external connection terminals around the side surface of the BGA module, so that high-density mounting can be performed on a printed wiring board for mounting a module such as a motherboard (hereinafter referred to as a “BGA module mounting board”). It is possible. Ball electrodes are arranged in a grid on the BGA module mounting substrate, and are electrically connected to external connection pads of the module substrate on which the semiconductor element (semiconductor chip) is mounted via these ball electrodes. Even in this case, high-density mounting is possible as described above.

In the BGA module substrate and the BGA module mounting substrate, ball-shaped electrode pads to which ball-shaped electrodes are melt-bonded are arranged on a surface of one side in a grid shape. The conductor pattern in the planar position of the ball-shaped electrode pad forming region required for electrical wiring to each of these ball-shaped electrode pads mainly separates the ball-shaped electrode pad forming surface from the insulating layer. It is formed on the surface. The conductor pattern and the ball-shaped electrode pad are formed at a planar position of each of the ball-shaped electrode pads or a plane position close to each of the ball-shaped electrode pad electrodes, and the grid interval of the array of the ball-shaped electrode pads Are electrically connected via via holes arranged in a plane in a grid shape having substantially the same grid interval (see Patent Document 1 and Patent Document 2).
JP-A-8-288658 JP 2000-261110 A

  As described above, in a conventional printed wiring board such as a BGA module substrate or a BGA module mounting substrate, via holes are formed at planar positions in a grid shape with a predetermined grid interval. As a result, the via hole interval is the same in both of the two orthogonal directions that define the grid. For this reason, in the region where the via hole is arranged, the ease of pattern wiring is the same regardless of whether it extends in either of the two directions.

  By the way, when the arrangement of the electrode terminals for external connection of the ball grid array is adopted, it is necessary to perform wiring for each ball electrode pad on the BGA module substrate or the BGA module mounting substrate. The wiring preferably has a short path and is smooth, but in a region where a via hole is formed, the wiring usually tends to extend almost radially from the center of the region. That is, when this is expressed in two dimensions, it becomes as follows. When paying attention to a via hole, the extending direction of the conductor pattern formed in the vicinity of the via hole is the side of the grid that defines the placement position of the ball-shaped electrode, the side having the shortest distance from the via hole. There is a tendency to be a direction having a large component in a direction orthogonal to the direction in which the edge extends. For this reason, in the conventional BGA module substrate and BGA module mounting substrate, the arrangement of via hole formation positions provided corresponding to the respective ball-shaped electrodes is appropriate for the necessary pattern wiring. It was difficult.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a printed wiring board capable of easily performing a smooth conductor pattern wiring with a short distance.

  The printed wiring board of the present invention is formed on the surface of one side of the first insulating layer and the first insulating layer, and a plurality of protruding electrode terminals arranged in a grit shape defined by two directions orthogonal to each other A plurality of electrode pads each melt-bonded to the one side; formed on the other side opposite to the one side of each of the plurality of electrode pads, non-penetrating on the one side, A plurality of non-penetrating via holes that connect each electrode pad and the other side of the first insulating layer, and at least one of the non-penetrating via holes is the closest of the grid. Orthogonal to the adjacent edge direction so that the center axis interval is larger than the grid interval with respect to at least one non-penetrating via hole adjacent in the adjacent edge direction in which the edge extends. That is formed in a planar position shifted include direction components, it is a printed wiring board, characterized in.

  In this printed wiring board, at least one of a plurality of non-through via holes formed on the other side of each of the plurality of electrode pads including a region where each of the plurality of protruding electrode terminals arranged in a grid shape is melt-bonded. One non-penetrating via hole includes a directional component orthogonal to the adjacent edge direction so that the central axis interval is larger than the grid interval with respect to at least one non-through via hole adjacent in the adjacent edge direction. It is formed in the plane position shifted by. Therefore, the distance between the central axis of the at least one non-penetrating via hole and the central axis of the non-penetrating via hole adjacent in the direction orthogonal to the adjacent edge direction (that is, the distance between non-penetrating via hole lands) is short. Although it may become, the distance with the center axis | shaft of said adjacent at least 1 non-penetrating via hole can be enlarged in a near edge direction.

  For this reason, compared with the case where the non-penetrating via holes are arranged in a grid shape, there is a large component in the vicinity edge direction near the position where the at least one non-penetrating via hole is formed on the other side of the first insulating layer. A conductor pattern extending in the direction may be difficult to wire, but a conductor pattern extending in a direction having a large component in a direction orthogonal to the adjacent edge direction is easily wired. That is, in this printed wiring, when the conductor pattern formed on the other surface of the first insulating layer tends to be substantially along the direction radially extending from the center position of the grid, the conductor pattern Wiring is easy.

  Further, the non-penetrating via hole connects the other side of the first insulating layer and the electrode pad, but does not penetrate on the electrode pad side. That is, there is no opening in the electrode pad, and the surface on one side thereof is flat. For this reason, the height of the protruding electrode terminal that is melt-bonded to the surface on one side of the electrode pad can be made uniform.

  In the printed wiring board of the present invention, at least one second insulating layer sequentially formed on the other side of the first insulating layer; and formed on one side insulating layer located on the one side of each of the second insulating layers A plurality of non-penetrating via holes formed on the other side of the land region of the formed via hole and interconnecting the via hole formed in the one insulating layer and the other side of the second insulating layer; Furthermore, it can be set as the structure provided.

  Here, as will be described later, the non-through via holes formed in the second insulating layer are arranged so as to be aligned with the via holes formed in the one insulating layer (hereinafter referred to as “stack arrangement”). As long as it is formed on the other side of the land region of the via hole formed in the one-side insulating layer, an arrangement in which the central axes are shifted (hereinafter referred to as “sequential arrangement”). Any of these sequences may be used. In this case, the area of the via hole forming region for interlayer connection on the surface of the second insulating layer can be minimized, so that a larger region can be secured for the wiring of the conductor pattern on the surface. it can.

  Furthermore, the land region refers to a region formed by plating or the like around the hole of the non-through via hole. When the non-penetrating via hole is via-fill plated, it includes a hole region filled by plating or the like in addition to the region formed in the periphery.

  In the printed wiring board of the present invention, the at least one non-penetrating via hole may be arranged on the outermost peripheral portion of the plurality of non-penetrating via holes. Here, the conductor pattern connecting the inside of the grid and the outside of the grid through the via holes is most concentrated on the outermost periphery. Accordingly, at least one of the non-penetrating via holes arranged on the outermost periphery is adjacent to at least the adjacent edge direction (that is, the direction of the outermost periphery where the at least one non-penetrating via hole is arranged). The distance between one non-penetrating via hole can be increased.

  In the printed wiring board of the present invention, when the plurality of protruding electrode terminals are arranged in a peripheral type, the at least one non-penetrating via hole is further provided, and the innermost circumference of the plurality of non-penetrating via holes is further increased. Can be arranged in the part. Here, in the case of the peripheral arrangement, the conductor pattern that connects between the inside of the grid and the outside of the grid through the via holes may concentrate on the innermost peripheral portion. Accordingly, the distance between at least one of the non-penetrating via holes arranged in the innermost periphery and at least one non-penetrating via hole adjacent in the vicinity edge direction can be increased.

  In the printed wiring board of the present invention, the at least one non-penetrating via hole is a plurality of specific non-penetrating via holes arranged substantially continuously along the adjacent edge direction, and the plurality of specific via holes However, it can be set as the structure currently formed in the plane position shifted alternately in the direction orthogonal to the said adjacent edge direction. In this case, it is possible to lengthen all of the intervals between the adjacent specific via holes in the plurality of specific via holes.

  As described above, according to the printed wiring board of the present invention, in a printed wiring board such as a BGA module board or a BGA module mounting board on which a plurality of pads to which the protruding electrode terminals arranged in a grid are welded are formed. It is possible to easily make the wiring of the conductor pattern a smooth and short distance.

  In addition, since the non-through via hole is employed on the electrode pad side, the height of the protruding electrode terminal can be made substantially uniform.

  An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the printed wiring board 10 of the present embodiment is a BGA module substrate used for the BGA module 100, and includes a semiconductor element 20 having a large number of bonding pads 22 formed on the surface in the + Z direction side. The solder balls 30 are mounted on the surface in the + Z direction side via the adhesive 29, and a large number of solder balls 30 are mounted on the surface in the −Z direction side.

  The printed wiring board 10 is formed on the surface in the + Z direction side of the insulating layer 11 corresponding to the bonding pads 22 of the semiconductor element 20 as comprehensively shown in FIG. 1 and FIG. 2 which is an XZ sectional view. Bonded pads 12 and conductor patterns 13 connected to the bonding pads 12 are formed. The bonding pad 22 and the bonding pad 12 are electrically connected by a bonding wire 25.

  In the printed wiring board 10, solder ball pads 14 formed corresponding to the bonding pads 12 are formed on the surface of the insulating layer 11 on the −Z direction side. The conductor pattern 13 formed on the surface of the insulating layer 11 on the + Z direction side and the solder ball pad 14 formed on the surface of the insulating layer 11 on the −Z direction side provide interlayer connection between both surfaces of the insulating layer. It is electrically connected by a non-through via hole 15 formed for the purpose. The non-penetrating via hole 15 is non-penetrating on the solder ball pad 14 side. For this reason, the solder ball pad 14 is a pad on a plate having no opening.

  As shown in FIG. 3, these solder ball pads 14 are arranged in a grid on the −Z direction side surface of the printed wiring board 10 (that is, on the −Z direction side surface of the insulating layer 11). In this embodiment, the solder ball pads 14 are arranged on the grid in a peripheral arrangement in which the solder ball pads 14 are not arranged at the center.

  The solder ball pads 14 except for the outermost periphery have a circular shape, and their center points are arranged on the grid with the grid interval a almost accurately. Then, non-through via holes 15 corresponding to the solder ball pads 14 are formed with an axis parallel to the Z axis passing through the center point as a central axis.

  On the other hand, the solder ball pads 14 arranged on the outermost periphery have a mixture of circular and elliptical shapes, and the non-penetrating via holes 15 corresponding to the solder ball pads 14 are formed on the solder ball pads 14. An axis parallel to the Z axis passing through the center point is not formed as the center axis. That is, among the solder ball pads 14 arranged on the outermost periphery, the non-through via holes 15 corresponding to the solder ball pads 14 arranged along the grid line XE parallel to the X axis are alternately arranged in the Y axis direction. Is formed at a planar position shifted from the grid line XE. As a result, in the non-through via holes 15 arranged along the grid line XE, the distance between the central axes of the adjacent non-through via holes 15 is longer than the grid interval a.

  The shape of the corresponding solder ball pad 14 is circular or elliptical depending on the amount of deviation of each non-through via hole 15 arranged along the grid line XE from the grid line XE in the Y-axis direction. It is made into a shape. Further, the shape of the solder ball pads 14 is such that the area where the solder balls 30 are melt-bonded can be ensured after the plane position of the center of the solder balls 30 to be melt-bonded is accurately set as a grid point. Yes.

  Further, among the solder ball pads 14 arranged on the outermost periphery, the non-through via holes 15 corresponding to the solder ball pads 14 arranged along the grid line YE parallel to the Y axis are alternately arranged in the X axis direction. Is formed at a plane position shifted from the grid line YE. As a result, in the non-through via holes 15 arranged along the grid line YE, the central axis of the adjacent non-through via holes 15 is the same as in the case of the non-through via holes 15 arranged along the grid line XE. The inter-distance is longer than the grid interval a.

  The shape of the corresponding solder ball pad 14 extends along the grid line XE in accordance with the amount of deviation in the X-axis direction from each grid line YE of the non-through via holes 15 arranged along the grid line YE. As in the case of the solder ball pads 14 arranged in this manner, they are round or elliptical. Further, the shape of the solder ball pads 14 is the same as the case of the solder ball pads 14 arranged along the grid line XE. In addition, the shape is such that a region for melting and joining the solder balls 30 can be secured.

  The non-penetrating via hole 15 described above is arranged at the position shown in FIG. 4 on the surface on the + Z direction side of the printed wiring board 10. That is, at the outer edge portion in the X-axis direction where the conductor pattern 13 extending in the direction in which the X-axis direction component is large from the bonding pad 12 is concentrated, the distance between the non-through via holes 15 arranged along the Y-axis direction is The outermost non-penetrating via hole 15 is disposed at a position longer than the grid interval a. Further, at the outer edge portion in the Y-axis direction where the conductor pattern 13 extending in the direction in which the Y-axis direction component is large from the bonding pad 12 is concentrated, the distance between the non-through via holes 15 arranged along the X-axis direction is as follows. The outermost non-penetrating via hole 15 is disposed at a position longer than the grid interval a.

  For this reason, the formation of the conductor pattern 13 that connects the bonding pad 12 and the corresponding non-through via hole 15 when compared with the case where the plane position of the central axis in all the non-through via holes 15 is a grid point. However, it is easily performed while maintaining the width of the conductor pattern 13, the shortness of the wiring path, and the smoothness of the wiring path.

  The printed wiring board 10 described above is manufactured as follows.

  First, when the printed wiring board 10 is manufactured, for example, the solid copper pattern 17U is formed on the surface in the + Z direction, and the solid copper pattern 17L is formed on the surface in the −Z direction, and the insulating layer 11 is made of a glass epoxy material. A copper-clad glass epoxy substrate is used as a starting material 10A (see FIG. 5A). In addition, a copper clad glass polyimide substrate can also be employed as a starting material.

  An opening 15A is formed at the formation position of the above-described non-through via hole 15 in the starting material 10A. The opening 15A is formed so as to extend from the + Z direction side surface of the copper pattern 17U to the + Z direction side surface of the copper pattern 17L (see FIG. 5B). When forming the opening 15A, first, the formation region of the non-penetrating via hole 15 on the + Z direction side surface of the copper pattern 17U is blackened. Next, the blackened region is irradiated with laser light having a predetermined energy from the + Z direction side to form an opening 15A.

  Next, copper plating is performed on the + Z direction side surface of the remaining copper pattern 17U, the side surface of the opening 15A, and the bottom surface of the opening 15A (that is, the + Z direction side surface of the copper pattern 17L in the opening 15A), A conductor film 18 is formed (see FIG. 5C). Such copper plating can be performed using, for example, a copper sulfate plating bath having the composition shown in Table 1 below.

  Next, using the subtract method, the copper patterns 17U and 17L and the conductor film 18 other than the formation region of the bonding pad 12, the conductor pattern 13, the solder ball pad 14, and the non-through via hole 15 are removed. In this subtract method, first, a dry film resist, for example, an acrylic resin-based dry film resist (HW440, manufactured by Hitachi Chemical Co., Ltd.) is laminated on the entire surface of the copper pattern 17 on the + Z direction side surface and the −Z direction surface. .

  Next, the resist is removed from the region where the above-described conductor pattern 13 is to be formed on the surface of the copper pattern 17U on the + Z direction side by a known photolithography method, and etching is performed. Thereafter, the remaining dry film resist is removed.

  As a result, the bonding pad 12 and the conductor pattern 13 are formed on the surface of the insulating layer 11 on the + Z direction side, and the solder ball pad 14 is formed on the surface of the insulating layer 11 on the −Z direction side. Further, a non-penetrating via hole 15 for electrically connecting the conductor pattern 13 and the solder ball pad 14 is formed (see FIG. 6A).

Then, on the surface area excluding the bonding area of the bonding wire 25 on the surface in the + Z direction side of the bonding pad 12, the fusion bonding area of the solder ball 30 on the −Z direction side of the solder ball pad 14, and the mounting area of the semiconductor element 20. Then, a solder resist 16 having a desired thickness is formed (see FIG. 6B). Such solder resist 16 can be formed, for example, by applying AUS503 manufactured by Taiyo Ink Co., Ltd. to both sides by screen printing.
The printed wiring board 10 is manufactured as described above.

  In the BGA module 100, after the printed wiring board 10 is manufactured, the semiconductor element 20 is mounted on the surface on the + Z direction side of the printed wiring board 10 via the adhesive 29, and the bonding pad 22 and the bonding pad 12 are mounted. The bonding wires 25 are wired between the solder balls and the solder balls are melt bonded to the −Z direction side of the solder ball pads 14.

  As described above, in the printed wiring board 10 of the present embodiment, the non-through via holes 15 formed on the + Z direction side of the solder ball electrode pads 14 arranged in a grid are arranged on the outermost periphery. Are formed at planar positions that are alternately displaced in a direction orthogonal to the arrangement direction. As a result, in the non-through via holes 15 arranged on the outermost periphery, the conductor patterns 13 extending in the direction in which the component in the direction orthogonal to the arrangement direction extends are concentrated, but the non-through via holes adjacent to each other in the arrangement direction. The distance between them is longer than the grid spacing. For this reason, the conductor pattern 13 can be easily formed while maintaining the width of the conductor pattern 13, the shortness of the wiring path, and the smoothness of the wiring path.

  Further, the non-penetrating via hole 15 is non-penetrating on the solder ball pad 14 side. That is, the solder ball pad 14 does not have an opening and has a flat plate shape. For this reason, the height of the solder ball 30 melt-bonded to the surface in the −Z direction of the solder ball pad 14 can be made uniform.

  In the above embodiment, the conductor pattern 13 is provided between the bonding pad 12 outside the formation region of the non-penetrating via hole 15 and the corresponding non-penetrating via hole 15. The case where the conductor pattern 13 is concentrated on the above has been described. On the other hand, when the conductor pattern is concentrated on the innermost peripheral portion, the non-penetrating via holes 15 arranged at the innermost periphery are arranged at planar positions alternately shifted in the direction orthogonal to the arrangement direction. Can be formed. Accordingly, the conductor pattern can be easily formed while maintaining the width of the conductor pattern, the shortness of the wiring path, and the smoothness of the wiring path. In addition, when the conductor pattern is concentrated on both the outermost periphery and the innermost periphery, the non-penetrating via holes 15 arranged on both the outermost periphery and the innermost periphery are alternately arranged in a direction orthogonal to the arrangement direction. It can be formed at a shifted plane position. Accordingly, the conductor pattern can be easily formed while maintaining the width of the conductor pattern, the shortness of the wiring path, and the smoothness of the wiring path.

  As long as the connection terminals exist outside the solder balls, any of wire bonding, flip chip, and TAB connection can be used for bonding.

  In the above embodiment, the case where the solder balls 30 are arranged in a peripheral type has been described. On the other hand, when the solder balls 30 are arranged in a full grid type, the conductor pattern is concentrated on the outermost periphery. Even in this case, if the non-through via holes 15 arranged on the outermost periphery are formed at planar positions alternately displaced in the direction orthogonal to the arrangement direction, the width of the conductor pattern, the shortness of the wiring path, and The conductor pattern can be easily formed while maintaining the smoothness of the wiring path.

In the above embodiment, the case where the printed wiring board 10 is a double-sided printed wiring board has been described. However, the present invention can be applied to a multilayer printed wiring board as in the above embodiment. . That is, as shown in FIG. 7, the insulating layer 11 ₂ formed with the non-through via hole 15 _ST2 is laminated in the + Z direction of the insulating layer 11 ₁ formed with the non-through via hole 15 _ST1 , and further, the insulating layer 11 _{2 is formed.} The non-through via holes 15 _ST3 formed in the + Z direction are laminated with the insulating layer 11 ₃ so that the center axis in the Z-axis direction of each non-through via hole can be aligned to form a stack arrangement.

_{Alternatively} , the insulating layer 11 ₂ formed with the non-through via holes 15 _SQ2 and 15 _{SQ2 ′} is laminated in the + Z direction of the insulating layer 11 ₁ formed with the non-through via holes 15 _SQ1 and 15 _{SQ1 ′.} Insulating layer 11 _{3 in} which non-through via holes 15 _SQ3 and 15 _{SQ3 ′} are formed in the + Z direction of ₂ is laminated, and so on, in the land region or pad region formed in the + Z direction of each insulating layer. In order to connect the holes, the central axes in the Z-axis direction can be shifted to form a sequential arrangement.

  In FIG. 7, the non-penetrating via hole 15 is filled by via fill plating. Moreover, in FIG. 7, the same code | symbol is attached | subjected to the element similar to the case of said embodiment.

  By adopting the stack arrangement or sequential arrangement as described above, interlayer connection can be made by non-through via holes, so that a larger wiring area can be secured on each wiring surface.

  In FIG. 7, the case where three insulating layers are laminated is described as an example. However, the number of insulating layers to be laminated may be two, and may be four or more as desired.

  In the above embodiment, the case where the printed wiring board 10 is a BGA module substrate has been described. However, the present invention can be applied to a BGA module mounting substrate such as a motherboard in the same manner as in the above embodiment. Can be applied.

  As described above, the printed wiring board according to the present invention is useful as a printed wiring board to which the protruding electrode terminals arranged in a grid shape are melt-bonded, and particularly used as a BGA module substrate or a BGA module mounting substrate. Suitable for

It is an external view for demonstrating the structure of the printed wiring board which concerns on one Embodiment of this invention. It is sectional drawing for demonstrating the structure of the printed wiring board of FIG. FIG. 2 is a plan view of a part of the printed wiring board of FIG. 1. FIG. 2 is a rear view of a part of the printed wiring board of FIG. 1. FIG. 3 is a view (No. 1) for describing a manufacturing process of the printed wiring board of FIG. 1; FIG. 3 is a diagram (part 2) for explaining a manufacturing process of the printed wiring board in FIG. 1; It is a figure for demonstrating the structure of the multilayer printed wiring board of a modification.

Explanation of symbols

10 ... printed circuit board, 11, 11 ₁ to 11 ₃ ... insulating layer, 12 ... bonding pad, 13 ... conductive pattern 14 ... solder ball pads (electrode _{pads), 15,15 ST1 ~15 ST3, 15} SQ1 ~ 15 _SQ3 , 15 _{SQ1 ′} to 15 _{SQ3 ′} ... Non-through via hole, 16. Solder resist, 20... Semiconductor element, 22. Bonding pad, 25. Bonding wire, 29. Adhesive, 30. Terminal).

Claims (5)

A first insulating layer;
A plurality of electrode pads formed on the surface of one side of the first insulating layer and melt-bonded to the one side, each of a plurality of protruding electrode terminals arranged in a grit shape defined by two directions orthogonal to each other When;
Each of the plurality of electrode pads is formed on the other side opposite to the one side, is non-penetrating on the one side, and each of the plurality of electrode pads and the other side of the first insulating layer are connected to each other. A plurality of non-through via holes for interlayer connection; and
At least one of the plurality of non-penetrating via holes has a central axis interval with respect to at least one non-penetrating via hole adjacent in the adjacent edge direction, which is the direction in which the edge of the nearest grid extends. A printed wiring board, wherein the printed wiring board is formed so as to be longer than a grid interval and is shifted in a plane position including an orthogonal direction component in the adjacent edge direction. At least one second insulating layer sequentially formed on the other side of the first insulating layer;
A via hole formed on the other side of the land region of the via hole formed on the one side insulating layer located on the one side of each of the second insulating layers, and the second insulation formed on the one side insulating layer. The printed wiring board according to claim 1, further comprising: a plurality of non-through via holes that connect the other side of the layers to each other.   The printed wiring board according to claim 1, wherein the at least one non-penetrating via hole is disposed on an outermost peripheral portion of the plurality of non-penetrating via holes. The plurality of protruding electrode terminals are arranged in a peripheral type,
The printed wiring board according to claim 3, wherein the at least one non-penetrating via hole is further disposed on an innermost peripheral portion of the plurality of non-penetrating via holes. The at least one non-penetrating via hole is a plurality of specific non-penetrating via holes that are arranged continuously substantially along the adjacent edge direction;
5. The print according to claim 1, wherein the plurality of specific non-penetrating via holes are formed at planar positions that are alternately shifted in a direction perpendicular to the adjacent edge direction. Wiring board.

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