JP4366647B2 - Wiring member manufacturing method - Google Patents

Description

  The present invention relates to a wiring member, a manufacturing method thereof, a wiring board using the wiring member, and a semiconductor package substrate.

  With recent high-density mounting of electronic components, improvement in wiring density of wiring boards has been demanded. Similar demands are also increasing in semiconductor packages mounted on wiring boards. In general, in the case of a semiconductor package, there are a type in which input / output terminals are arranged in a row around the package and a type in which the input / output terminals are arranged in multiple rows not only around but also inside. The former is typically QFP (Quad Flat Package). In order to increase the number of terminals, it is necessary to reduce the terminal pitch. However, in a region having a pitch of 0.5 mm or less, advanced technology is required for connection to the wiring board. The latter array type is suitable for increasing the number of pins because terminals can be arranged with a relatively large pitch. Conventionally, an array type is generally a PGA (Pin Grid Array) having connection pins, but connection with a wiring board is an insertion type and is not suitable for surface mounting. Therefore, a package called BGA (Ball Grid Array) that can be mounted on the surface has been developed.

  On the other hand, with the downsizing of electronic devices, the demand for further downsizing of the package size has increased. In order to cope with this downsizing, a so-called chip size package (CSP) having a size substantially equal to that of a semiconductor chip has been proposed. This is a package having a connection portion with an external wiring board, that is, an external connection terminal in the mounting region, not in the peripheral portion of the semiconductor chip. As a specific example, a polyimide film with bumps is bonded to the surface of a semiconductor chip, an electrical connection is made between the chip and a gold lead wire, and then epoxy resin or the like is potted and sealed (for example, see Non-Patent Document 1) ), Or metal bumps are formed on the temporary substrate at positions corresponding to the connection portions between the semiconductor chip and the external wiring substrate, the semiconductor chip is face-down bonded, and then transfer molded on the temporary substrate (for example, Non-Patent Document 2). See).

  In any of these semiconductor packages, the connection between the circuit formed on the package substrate and the connection terminal for connection between the circuit formed on the package substrate and the connection terminal for connection between the connection terminal and the semiconductor chip. Through holes and via holes are used for connection. For through-holes and via-holes, a method is generally used in which a connection terminal is provided by drilling or lasering in advance at the location to be the connection terminal of the base material, filling with solder or conductive paste, or through-hole plating or hole-filling plating However, this method has a limit in reducing the diameter of the hole, and the cost increases as the number of pins increases.

  Therefore, a method has been proposed in which conductive protrusions are provided on a metal foil in advance by a plating method, a printing method, or an etching method, and after the resin as a base material is embedded later or simultaneously, the metal foil or the wiring member is connected. ing. In order to improve the connection reliability in these methods, a method of applying a conductive resin, gold plating, solder plating or the like to the conductive protrusion head has been proposed.

In the past, the inventors have used a wiring member having conductive protrusions formed by etching a metal foil, embedded conductive protrusions (bumps) with resin, and used for wiring for interlayer connection. Developed. This semiconductor package is described in Patent Document 1, for example.
JP 2002-43467 A NIKKEI MATERIALS & TECHNOLOGY 94.4, No. 140, p18-19 Smallest Flip-Chip-Like Package CSP; The Second VLSI Packaging Workshop of Japan, p46-50, 1994

  In many cases, the wiring members having these conductive protrusions have a thickness of 5 to 100 μm, and as such, there is a problem that they are difficult to handle and easily damaged. In addition, the wiring board using the wiring member having the conductive projection and the package board are similarly thin and weak in strength.

  In addition, wiring boards and package substrates often require through holes such as positioning holes and slit holes. These holes are often formed after the wiring formation is completed by a cutting tool such as a drill or a router. When these holes are post-processed, the wiring-processed substrate contracts and expands due to the thermal history and processing stress of the processing process, so that there is a problem that the wiring position does not necessarily match the processing position. Further, when machining with a drill or a router, the shape of the hole is restricted because a large round (semicircle) is attached to the corner.

  The present invention improves the strength of the product when manufacturing a wiring board and a package substrate by using a wiring member in which conductive protrusions are formed in advance on a metal foil and a resin as a base material is embedded later. An object of the present invention is to provide a wiring member, a wiring board, a package substrate, and a method for manufacturing the wiring member that are easy to manufacture.

The present invention relates to each item described below.
(1) In the manufacturing method of a wiring member for forming a plurality of conductive protrusions to metals layer surface, the first metal layer, a multilayer having in this order at least three layers of the second metal layer and the third metal layer A step of preparing the metal foil, a step of removing the metal layer to leave the portion to be the conductive protrusion and exposing the second or third metal layer to form the conductive protrusion, and an insulating resin for embedding the conductive protrusion. The manufacturing method of the wiring member including the process of forming a dam in the metal layer surface along the outer periphery of a required part.
( 2 ) The wiring member described in ( 1 ), wherein the step of forming the dam is a step of removing the metal layer and forming the dam until the second or third metal layer is exposed, leaving a portion that becomes the dam. Manufacturing method.
( 3 ) The method for manufacturing a wiring member according to (1) or (2) , wherein the step of forming the conductive protrusion is a step of forming the conductive protrusion whose surface in contact with the metal layer surface is uneven.
( 4 ) The method for manufacturing a wiring member according to any one of ( 1 ) to ( 3 ), wherein the step of forming a dam is a step of forming a dam in which a surface in contact with the metal layer surface has an uneven shape.
( 5 ) The surface of the metal layer on which the conductive protrusions are formed before the step of removing the metal layer and forming the conductive protrusions until the second or third metal layer is exposed, leaving the portions that become the conductive protrusions. The manufacturing method of the wiring member described in any one of ( 1 )-( 4 ) including the process of sticking the tape for reinforcement on the opposite surface.
( 6 ) The surface of the metal layer on which the conductive protrusions are formed before the step of removing the metal layer and forming the conductive protrusions until the second or third metal layer is exposed, leaving the portions that become the conductive protrusions. The manufacturing method of the wiring member described in any one of ( 1 )-( 4 ) including the process of apply | coating the resin for reinforcement to the opposite surface.
( 7 ) After the step of removing the metal layer and forming the conductive protrusion until the second or third metal layer is exposed leaving the portion to be the conductive protrusion, the step of embedding the conductive protrusion with an insulating resin, A step of curing the insulating resin, a step of removing the second or third metal layer corresponding to the holding layer of a part of the conductive protrusions, and a removal of the conductive protrusions after removing the second or third metal layer corresponding to the holding layer. The manufacturing method of the wiring member described in any one of ( 1 )-( 6 ) including a process.
( 8 ) The method for manufacturing a wiring member according to ( 7 ), wherein the step of removing the conductive protrusion is a step of removing the conductive protrusion by etching.
( 9 ) The wiring according to ( 7 ), wherein the step of removing the conductive protrusion is a step of removing the conductive protrusion by applying a force to one surface of the conductive protrusion exposed from the insulating resin to push out the conductive protrusion. Manufacturing method of member.

  According to the present invention, by using a wiring member in which conductive protrusions are formed in advance on a metal foil and a resin serving as a base material is embedded later, workability is improved in manufacturing a wiring board and a semiconductor package substrate. Further, the strength of the product can be improved, and further drilling can be facilitated. The present invention does not perform drilling with a drill or laser, and does not perform solder, conductive paste, through-hole plating, hole-filling plating, etc., so that the diameter can be further reduced, cost can be kept low, and positioning holes, slit holes, etc. Since the through hole is not processed after the wiring formation is completed, the problem that the wiring position does not necessarily match the processing position can be solved.

  For example, a semiconductor as an interposer used in a semiconductor package may be used as a wiring board using a wiring member manufactured by the present invention, in which conductive protrusions are formed on a metal foil and an insulating resin to be a base material is embedded later. Other wiring boards such as a motherboard for mounting a package substrate, a semiconductor package and other electronic components can be mentioned.

  The present invention provides a metal foil, a plurality of conductive protrusions formed on the surface of the metal foil, an insulating resin embedding the plurality of conductive protrusions, and provided on the surface of the metal foil along an outer periphery of a necessary portion of the insulating resin. This is a wiring member made of a dam. The metal foil on which the conductive protrusions of the present invention are formed is not particularly limited as long as it is a metal foil generally used for a wiring board, but a copper foil is desirable from the viewpoint of economy and workability. Examples of the conductive protrusion formed on the surface of the metal foil include a metal body or a conductive paste. If it is a metal body, it can be formed on the surface of the metal foil by copper plating, nickel plating, tin plating, solder plating, etc. after the plating resist is formed. It can be formed on the surface. It is also possible to form a metal body which is a conductive protrusion by etching. In this case, a copper foil alone may be used, but the first and third metal layers are etched together with the second metal layer. It is preferable to use a three-layer metal foil which is a metal layer having a different thickness. When the first and third metal layers at this time are copper or a copper alloy, nickel, nickel alloy, titanium, chromium, tin, zinc, or the like is preferable as the second metal layer.

  The insulating resin used in the present invention may be any resin that has fluidity when embedded in the conductive protrusions. At this time, the application environment may be heated so that fluidity is obtained in the resin even at room temperature. Alternatively, a resin that is in the form of a sheet at normal temperature and is placed on the conductive protrusion and embedded with the conductive protrusion by heating, pressurizing, or the like may be used. Examples of insulating resins used include polyimide resins, polyamideimide resins, silicone resins, phenol resins, bismaleimide triazine resins, epoxy resins, acrylic resins and other thermosetting resins, polyphenylene sulfide resins, photosensitive polyimide resins, acrylic epoxies. Examples thereof include resins, thermoplastic elastomers such as ethylene, propylene, styrene, and butadiene, and liquid crystal polymers. Moreover, what mix | blended organic particle | grains and inorganic particle | grains with these resin can also be used. Examples of organic particles that can be blended into the resin include cured products of the aforementioned resins, and examples of inorganic particles include alumina particles, silicon dioxide (silica), glass fibers, and the like. These organic or inorganic particles preferably have an average particle size of 0.1 to 20 μm.

  In the present invention, when the insulating resin in a fluid varnish state before curing is applied to the surface of the wiring member having the conductive protrusions to a thickness where the conductive protrusions are embedded with the insulating resin by printing, The insulating resin in the varnish state preferably has a viscosity of 3 to 70 Pa · s during printing. As a printing method, a screen printing method using a mesh screen mask, a metal mask, etc., and a method of applying a resin to a uniform thickness by using a squeegee, a blade, etc. directly on a wiring member, leaving a gap or a gap, and There is a method of transferring a resin onto a wiring member after applying the resin to a drum or a board. Moreover, the method of performing these operations under vacuum is also effective in eliminating unfilled portions.

  A plurality of these insulating resins may be used. For example, in order to reduce warping of the base material, for example, a structure in which an insulating resin having good adhesion is supplied thinly on the surface of the conductive protrusion and the metal foil as the first layer insulating resin, and an insulating resin excellent in strength is embedded thereon. A thin insulating resin having good adhesion is formed as the first insulating resin, a thick insulating resin having a coefficient of expansion close to that of the base material is formed as the second insulating resin, and the warp is adjusted as the third insulating resin. Therefore, a structure in which an appropriately adjusted insulating resin is embedded may be used.

  In manufacturing a wiring board and a package substrate using a wiring member in which conductive protrusions are formed in advance on a metal foil and an insulating resin as a base material is embedded later, the present invention provides a wiring as a structure for improving workability. A structure in which a dam is provided on the outer periphery of the necessary portion of the insulating resin is effective so that the insulating resin can be buried only in the necessary portion of the insulating resin of the member so that the insulating resin does not flow into other than the necessary portion. In general, in the manufacture of a wiring board, the end of the wiring member has only a positioning marker or the like necessary for manufacturing, and is finally cut off to become an actual product. Therefore, if the insulating resin is supplied only to the actual product, the function as the product can be satisfied and the insulating resin to be used can be reduced. For example, if the panel 6 in FIG. 6 is a wiring member, the part that becomes the actual product is the frame part 7. It is only necessary to supply the insulating resin only to the frame portion 7. Further, if a dam structure is formed on the entire surface of the end portion of the wiring member that is not an actual product and the peripheral portion is thickened, the strength of the wiring member can be increased. In particular, as a wiring member having a plurality of conductive protrusions on the surface of the metal foil, the first metal of the multilayer metal foil having at least three layers of the first metal layer, the second metal layer, and the third metal layer in this order. In the wiring member formed by removing the layer until the second or third metal layer is exposed, leaving the portion that becomes the conductive protrusion, when forming the conductive protrusion, the portion that becomes the dam at the same time is formed. A dam shape can be easily formed by leaving the first metal layer and the second metal layer without etching. In this case, examples of the wiring member having a plurality of conductive protrusions on the surface of the metal foil include the following. The first and third metal layers are three-layer metal foils having different etching conditions from the second metal layer, and the first metal layer is formed into columnar bumps (conductive protrusions) by etching using a dry film resist. ) And the above-mentioned three-layer metal foil are etched using a dry film resist to make the first metal layer a columnar bump, and then the second metal layer is removed except for the lower part of the columnar bump. There is a metal foil that is etched away until the third metal layer is exposed. When the first and third metal layers at this time are copper or a copper alloy, examples of the second metal layer include nickel, a nickel alloy, titanium, chromium, tin, and zinc. Further, if conductive projections are formed in the frame portion 7 of FIG. 6 and the periphery of the frame portion 7 is a dam, the portion other than the frame portion of the panel 6 can be a dam. The first metal layer of the multi-layer metal foil having at least three layers of the first metal layer, the second metal layer, and the third metal layer in this order is left with the portions that become conductive protrusions and dams. In the method for manufacturing a wiring member that is removed until the second or third metal layer is exposed, the second metal layer and the third metal layer may be removed by etching, and a normal wiring board manufacturing process Etching solution used in (1) may be used.

  In addition, by providing a dam, when an insulating resin with high fluidity is used, sagging of the insulating resin is reduced and the thickness is stabilized. In particular, when the insulating resin is embedded by printing, it is effective because the gap between the wiring member and the mask and the gap between the squeegees can be easily made constant.

  When a dam structure is formed on the entire end surface of the wiring member that is not an actual product, warp distortion may easily occur due to a difference in expansion coefficient between the wiring member and the resin or a difference in the amount of curing shrinkage. In this case, it is also effective to create a stress relief by forming a space such as a slit or a hole in the part that hits the dam. The slit or hole may be a through hole or a blind hole. An insulating resin may be embedded in this space.

  As a wiring member having a plurality of conductive protrusions on the surface of the metal foil, the first metal layer of the multilayer metal foil having at least three layers of the first metal layer, the second metal layer, and the third metal layer in this order. In the wiring member formed by removing the second metal layer until the second or third metal layer is exposed leaving a portion that becomes a conductive protrusion, the dam forming portion of the first metal layer is simultaneously formed at the time of dam formation. It can be easily formed by selectively etching the portion corresponding to the slit and hole. These holes may be used as positioning holes for subsequent processing.

  In a wiring member with conductive protrusions formed on a thin metal foil, stress is likely to concentrate on the thin metal foil around the dam by providing a dam, and the thin metal foil tends to break at the boundary with the dam due to the handling of the manufacturing process. There is. Therefore, in the dam shape of the wiring member, the surface in contact with the metal foil surface is not a straight shape, but by making it an uneven shape, the adhesion area with the insulating resin is increased, and by reducing the straight part, it is difficult to break is important. Increasing the adhesion area leads to adhesion strengthening, and even if the straight part is reduced, even if it is partially broken, the breakage hardly propagates from the damaged part first. The example of the shape of this uneven structure was shown to Fig.1 (a)-(d). 1A to 1D show the dam shape of the surface in contact with the metal foil surface as viewed from the upper surface of the wiring member.

  An uneven shape as shown in FIG. 1 (a), an uneven shape using a triangle as shown in FIG. 1 (b), FIG. 1 (c) shows an uneven shape such as a keyhole to further increase the contact area, FIG. 1D shows a structure in which the adhesion area between the insulating resin and the dam side surface is large and the damage such as a crack is difficult to propagate due to the uneven shape of the protrusion bent into the L shape. FIG. 2 shows a plan view of a wiring member in which conductive protrusions are formed by etching and a portion of the semiconductor package substrate serving as a frame as viewed from above. The surrounding irregularities are dams 1.

  In the wiring member in which the conductive protrusions are formed on the metal foil, the shape of the conductive protrusions may be circular, square, uneven, or the like, and is not particularly limited. However, in the same manner as described above, in a wiring member in which conductive protrusions are formed on a thin metal foil, it is easy to concentrate stress on the thin metal foil around the conductive protrusions, and when the conductive protrusions are relatively large (2 mm square or more), A thin metal foil tends to be easily broken at the boundary with conductive protrusions due to the handling of the manufacturing process. Even in such a case, the shape of the conductive protrusions is not a straight shape on the surface in contact with the surface of the metal foil, but an uneven shape, thereby increasing the adhesion area with the insulating resin and reducing the straight portion, thereby making it difficult to break. This is preferable. Examples of the concavo-convex structure and shape include shapes similar to the shapes shown in FIGS. 1A to 1D, and FIGS. 1E to 1H except for the functional portion that becomes a dam. An uneven shape as shown, a triangular uneven shape, a keyhole uneven shape, an L-shaped uneven shape, and the like are preferable. Thereby, adhesion can be improved and propagation of destruction can be prevented.

  In a wiring board, in most cases, wiring is not applied to all parts. In particular, in the case of a substrate for a semiconductor package, semiconductor chips are often mounted in a frame shape as shown in FIG. 3, and both ends of the longitudinal side of the frame are used for transportation and positioning. There is only wiring for the positioning marker pattern. However, both ends of the frame are likely to be mechanically loaded during transportation. As the substrate thickness becomes thinner, strength measures are required.

  Embedding a dummy metal protrusion in a portion of the wiring board where wiring is not applied is effective in enhancing the strength of the wiring board. In order to obtain such a structure, in the wiring member having a plurality of conductive protrusions on the surface of the metal foil, in addition to the plurality of conductive protrusions used for the wiring, a plurality of dummy A wiring member having conductive protrusions may be used. A plurality of dummy conductive protrusions that are not scheduled to be wired may be used as dummy metal protrusions on the wiring board. In particular, as a wiring member having a plurality of conductive protrusions on the surface of the metal foil, the first of the multilayer metal foil having at least three layers of the first metal layer, the second metal layer, and the third metal layer in this order. The metal layer is left with a portion that becomes a conductive projection A (2 in FIG. 3) used for wiring and a portion that becomes a dummy conductive projection B (3 in FIG. 3) that is not scheduled to be wired. If it is a wiring member formed by the method of removing until the 2nd or 3rd metal layer is exposed, such a structure can be obtained easily, without increasing a process. If this structure is formed at the longitudinal end of the frame of the semiconductor package substrate, dummy conductive protrusions B3 can be formed densely as shown in FIG. 3, so that the strength can be greatly improved and it is very effective. .

  As an example of the shape and arrangement of the dummy conductive protrusions B, FIG. 4 shows the shape and arrangement of the dummy conductive protrusions B on the surface in contact with the surface of the metal foil. As the shape, a square as shown in FIGS. 4A and 4B, a circle and an ellipse as shown in FIGS. 4C and 4D, a diamond as shown in FIGS. 4E and 4F, and a figure. Examples include 4 (g) triangles, polygons such as hexagons in FIG. 5 (h), and complex shapes devised so that dummy conductive protrusions such as saddles as shown in FIG. 5 (i) are intertwined with each other. It is done. Note that the shape and arrangement shown in FIG. 4 are not limited as long as the shape is effective for strengthening the strength of the wiring board. As the arrangement, in addition to a lattice shape, a staggered pattern, and the like, a shape in which the protrusions intersect so that damage is not easily propagated to stress from one direction, for example, FIG. 4B, FIG. The arrangement as in i) is more effective in terms of strength. Note that the shape shown in FIG. 4 may be used for the conductive protrusion A used for wiring.

  Although it is desirable to reduce the occupation ratio of the insulating resin by making the gap between the dummy metal projections smaller, there is a limit to the gap that can be formed. As a wiring member having a plurality of conductive protrusions on the surface of the metal foil, the first metal layer of the multilayer metal foil having at least three layers of the first metal layer, the second metal layer, and the third metal layer in this order. Is removed until the second or third metal layer is exposed, leaving a portion that becomes the conductive protrusion A and a portion that becomes the dummy conductive protrusion B, there is a gap that can be formed depending on the thickness of the first layer. Limited. Specifically, the minimum gap width needs to be 1 time or more of the thickness of the first layer. Further, if the size (width, etc.) of the dummy metal protrusion is too small, the occupation ratio of the insulating resin increases and the strength of the wiring member decreases. For example, if the dummy conductive protrusion B has a square shape, The width (side) is preferably at least twice as large as the gap width between the conductive protrusions. In addition, if the size (width, etc.) of the dummy metal projection is increased, the occupation ratio of the insulating resin can be reduced. However, the metal projection is likely to be plastically deformed, and is also likely to be deformed due to a contraction difference with the resin. . Therefore, in the case of the shape of the dummy conductive protrusion B shown in FIG. 4 (square, circle, ellipse, rhombus, triangle, hexagon, saddle, etc.), the external dimensions (diameter, diagonal, side, etc.) are as follows: 5mm or less is desirable.

  As a wiring member having a plurality of conductive protrusions on the surface of the metal foil, the first metal layer of the multilayer metal foil having at least three layers of the first metal layer, the second metal layer, and the third metal layer in this order. The second and third metal layers are thin (thickness 1 to 3) when handling the wiring member formed by removing the second protrusion or the third metal layer until the second or third metal layer is exposed, leaving a portion that becomes a conductive protrusion. 10 μm), it is effective to apply a reinforcing tape or apply a reinforcing resin to the opposite surface on which the protrusions are formed in advance before forming the conductive protrusions. Thereby, after the etching of the first metal layer, deformation of the second and third layer metals due to wrinkles or the like can be prevented.

  As a reinforcing tape, it is necessary to withstand chemicals used for development, etching, and resist peeling, and to withstand solvents, heat, and the like during application of insulating resin, drying, and curing. The tape material preferably has a thermal expansion coefficient close to that of the wiring member. Examples of tape materials include highly heat-resistant polyimide tape, paper, polyphenylene sulfide resin, metal tape using aluminum, copper, iron, and the like, and examples of tape adhesive materials include silicon resin and acrylic resin. . Since the tape to be used is removed after embedding the insulating resin, it is preferable that there is little adhesive residue and the adhesive strength is easy to peel off (peel strength 0.5 KN / m or less). Use of a tape whose adhesive strength is reduced by heat is convenient because it is difficult to peel off during processing, and it is easy to peel off after the insulating resin is cured.

  As a reinforcing resin, it is necessary to withstand chemicals used for development and etching resist peeling, and to withstand solvents, heat, and the like during application, drying, and curing of insulating resin. Moreover, it is preferable that a thermal expansion coefficient is near with a wiring member. Examples of resin materials include polyimide resins, polyamideimide resins, silicone resins, phenol resins, bismaleimide triazine resins, epoxy resins, acrylic resins, and other thermosetting resins, polyphenylene sulfide resins, photosensitive polyimide resins, acrylic epoxy resins, ethylene, There are thermoplastic elastomers such as propylene, styrene and butadiene, and liquid crystal polymers. Moreover, in order to match the coefficient of thermal expansion with the wiring member, it is also possible to use those resin materials blended with organic particles or inorganic particles. Examples of the organic particles that can be blended in the resin material include a cured product of the resin material described above, and examples of the inorganic particles include alumina particles, silicon dioxide (silica), glass fibers, and the like. Since the reinforcing resin is removed after embedding the insulating resin, it is preferable that there is little adhesive residue and the adhesive strength is easy to peel off (peel strength 0.5 KN / m or less). Use of a resin whose adhesion and adhesive strength is reduced by heat is convenient because it is difficult to peel off during processing and easily peels off after the insulating resin is cured.

  In addition, the same effect as that of the reinforcing tape or the reinforcing resin can be realized by using, for example, the following wiring member. As a wiring member having a plurality of conductive protrusions on the surface of the metal foil, at least four layers of a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer having a thickness of 10 μm or more are provided. Using the multilayer metal foil having the order, the first metal layer is removed until the second or third metal layer is exposed, leaving a portion to be a conductive protrusion. After embedding the insulating resin, the fourth metal layer serving as a reinforcement is selectively removed. At this time, if the fourth metal layer is removed by etching, the fourth metal layer is a metal that can be selectively etched with the first metal layer, the second metal layer, and the third metal layer. It is desirable to be. In addition, if the adhesion between the fourth metal layer and the third metal layer is 0.5 KN / m or less in terms of peel strength, the fourth metal layer can be removed by peeling.

  As a method for forming a through hole in a wiring member or a wiring board, a first metal layer of a multilayer metal foil having at least three layers of a first metal layer, a second metal layer, and a third metal layer in this order. In the wiring member formed by removing the second metal layer until the second or third metal layer is exposed, leaving the portion that becomes the conductive protrusion, and the conductive protrusion C ( In FIG. 3, 4) is prepared, filled with an insulating resin, and cured, and then the second and third metal layers of the portion holding the conductive protrusion C are removed, and then the conductive protrusion C is removed. Thus, there is a method of forming a through hole. If this method is used, a plurality of holes can be simultaneously formed in a plurality of types of hole shapes.

  Moreover, when forming a through-hole, since a hole is processed with a drill or a router in a general manufacturing process, the shape of the hole is restricted because a large round (semi-circle) is attached to the corner. However, according to the present invention, the shape of the through hole can be any shape as long as the first metal layer can be etched. Of course, a slit, such as a conductive protrusion D (5 in FIG. 2) for a slit hole in FIG.

  Since the shape of the through hole is determined by etching, for example, when etching is performed using a square negative mask, the four corners are etched and rounded. This depends on the etching ability of the etchant and the thickness of the metal layer to be etched. As a method of reducing the roundness, there is a method in which the corner portion of the negative mask is thickened by the amount to be etched so that it becomes an acute angle after etching.

  As a method of removing the conductive protrusions C that become the through holes, after filling and curing the insulating resin, removing the second and third metal layers of the portions holding the conductive protrusions C, and then removing the conductive protrusions C other than the conductive protrusions C. There is a method of protecting the conductive protrusions with a dry film or the like and removing the conductive protrusions C by etching. Further, there is a method of removing mechanically by applying an external pressure to one surface of the conductive protrusion exposed from the insulating resin C and pushing out the conductive protrusion.

  By applying this technique, a blind hole can be formed in the wiring board. That is, the first metal layer of the multilayer metal foil having at least three layers of the first metal layer, the second metal layer, and the third metal layer in this order becomes a portion that becomes a conductive protrusion and a blind hole. Remove the conductive protrusion C until the second or third metal layer is exposed, and after filling with insulating resin, protect the portions other than the conductive protrusion C that will become blind holes with a dry film or the like. Only the C first metal layer is etched away. Thereby, the blind hole which makes the 2nd, 3rd metal layer a bottom part can be formed. Still further, the second metal layer can be removed by etching to form a blind hole having only the third metal layer as a bottom.

  As an example of an external pressure for removing the conductive protrusion C, that is, a method of applying a force to one surface of the conductive protrusion C exposed from the insulating resin, a method of directly applying pressure with a slightly small protrusion close to the shape of the conductive protrusion C, There are methods such as blowing off with pressurized air. When applying external pressure, it is important to hold the periphery of the conductive protrusion C with a holding jig or the like so as not to damage the insulating resin around the hole. In addition, since the conductive protrusion C is formed by etching as the direction in which the external pressure is applied, the area of the upper end of the protrusion (on the first metal layer side) tends to be smaller than the bottom surface. If the external pressure is applied from the metal layer side of 1), the insulating resin around the hole is less likely to be damaged.

Hereinafter, the present invention will be described more specifically with reference to examples of the present invention, but the present invention is not limited to these examples.
(Example 1)
An embodiment of the present invention will be described with reference to the drawings. FIG. 5 shows a cross section of each manufacturing process of the wiring member and the semiconductor package substrate of the present invention.
FIG. 5A shows a cross-sectional view in which a reinforcing tape 13 is attached to a three-layer metal foil. In the three-layer metal foil, the first layer is a copper layer 10 having a thickness of 70 μm, the second layer is a nickel layer (barrier layer) 11 having a thickness of 0.6 μm, and the third layer is a copper layer (circuit layer) 12 having a thickness of 10 μm. A three-layer metal foil (manufactured by Nippon Electrolytic Co., Ltd.) was cut into a size of 270 × 270 mm and prepared. As the reinforcing tape 13, a heat-resistant TPS tape (ENPT-480, manufactured by Teraoka Seisakusho) and a thickness of 50 μm were used. This reinforcing tape 13 was attached to the third layer 12 side of the three-layer metal foil with a roll laminator (MS Lampet L-650, manufactured by Meiko) so as not to be wrinkled at room temperature (25 ° C.).

  FIG. 5B is a cross-sectional view obtained by etching the first metal layer and the second metal layer of the three-layer foil leaving portions that become conductive protrusions. An etching pattern is formed on the first layer side of the metal foil (manufactured by Nippon Electrolytic Co., Ltd.) using a photo dry film H-K350 (manufactured by Hitachi Chemical Co., Ltd.), and an A process liquid (ammonia copper) manufactured by Meltex Co., Ltd. The first copper layer 10 is selectively etched with an alkaline etchant comprising a complex salt (20-30 wt%, ammonium chloride 10-20 wt% and ammonia 1-10 wt%). Next, the exposed portions of the nickel layer 11 other than the conductive protrusions of the nickel layer 11 as the second metal layer are selectively removed with a nickel stripping solution made of nitric acid / hydrogen peroxide aqueous solution, as shown in FIG. In addition, a cylindrical conductive protrusion A 2 having a diameter of 250 μm made of copper and nickel, a dummy conductive protrusion B 3 for improving the strength of a wiring board, a conductive protrusion C 4 for forming a through hole, and a liquid dripping when forming an insulating resin A dam structure 1 for prevention was formed. In order to improve the adhesion with the insulating resin, the exposed surface of the third copper layer 12 (conductive protrusion side) having a thickness of 10 μm and the surface of the conductive protrusion are treated with an NBDII treatment that is a surface roughening treatment agent for chemical treatment. Treated with liquid (Kashihara Densan Co., Ltd., containing 7.5% by weight sulfuric acid, 3.8% by weight phosphoric acid and 4.0% by weight hydrogen peroxide), and exposed and exposed end faces and side surfaces, exposed thickness A roughened surface having an average of 2 μm was obtained on the surface of the copper layer 12 having a thickness of 10 μm. Since the reinforcing tape 13 was applied, the third copper layer 12 was not damaged such as wrinkles in these operations.

  FIG. 5C is a cross-sectional view in which the insulating resin 14 is embedded in the etched portion of the three-layer foil leaving the portions that become conductive protrusions in the first metal layer and the second metal layer. As the insulating resin 14, KS6600 (manufactured by Hitachi Chemical Co., Ltd.) made of silicone-modified polyamideimide resin was used. The above resin having a viscosity of 40 pa · s (25 ° C.) in the varnish state can be applied to all of the plurality of conductive protrusions with a printing machine (VE-500, manufactured by Toray Engineering Co., Ltd.) and has the same size as the outer peripheral shape of the dam. Printing was performed through a metal mask having a thickness of 80 μm that was opened. By drying at 120 ° C. for 30 minutes, a semi-cured state is obtained, and the solvent component is volatilized, resulting in a cross-sectional shape in which the insulating resin of the conductive protrusion is raised. The thickness of the raised insulating resin on the surface of the conductive protrusion was 30 μm.

  FIG. 5D is a cross-sectional view in which the embedded insulating resin 14 is polished to expose the heads of the conductive protrusions. In order to expose the heads of the conductive protrusions embedded in the insulating resin, the semi-cured insulating resin 14 is polished with care using a commercially available abrasive paper (# 400 to # 2000) so as to be flat. The protruding head was exposed. Thereafter, the insulating resin 14 was cured by heating at 180 ° C. for 30 minutes and further at 220 ° C. for 30 minutes. Finally, the reinforcing tape 13 was removed by hand so as not to wrinkle.

  FIG. 5E shows a circuit 9 formed by polishing to expose the heads of the conductive protrusions and further etching the third copper layer 12. The third copper layer 12 was selectively etched with an alkaline etching solution made of Meltex A process liquid to form a circuit 9 connected to the conductive protrusion A2. In this case, the dummy copper conductive protrusion B 3 leaves the third copper layer 12, and the conductive protrusion C 4 for forming the through hole has the third copper foil 12 connected to the conductive protrusion C 4. It was removed so that the end face of was exposed. For these, one negative film was used for dry film lamination, exposure, etching, and peeling at a time.

  FIG. 5F is a cross-sectional view in which after the third copper layer 12 is etched to form the circuit 9, the conductive protrusion C 4 in a portion that becomes a through hole is removed. The conductive protrusion C4 and the hole of the jig are aligned on the jig having a hole slightly larger than the conductive protrusion C4 for forming the through hole, and the third copper layer 12 surface faces down. The member was placed, and the conductive protrusion C 4 was removed by vertically protruding the end face of the conductive protrusion C 4 from above with a metal bar slightly smaller than the through-hole forming protrusion C 4. Thereby, the through hole 20 was able to be formed. This was used as a wiring member.

  FIG. 5G is a cross-sectional view in which the solder resist 8 is applied to both sides after removing the conductive protrusions C 4 at the portions that become the through holes. A photosensitive solder resist is applied on both sides by screen printing except for the through-hole 20 part, and the resist such as a bonding pad for external connection and a ball pad part is removed by development and cured to form a solder resist 8 did. Thereafter, electrolytic nickel / gold plating (manufactured by Daiwa Denki Kogyo Co., Ltd.) was formed on the circuit surface not covered with the solder resist 8 and the exposed surface of the conductive protrusions, thereby obtaining a semiconductor package substrate.

  FIG. 5H is a cross-sectional view of the outer shape processed into a frame shape after the solder resist 8 is applied and electrolytic nickel / gold plating is performed. The external shape was machined using a router machine. As a result, a dummy conductive protrusion B3 is present at the periphery of the frame, and the strength of the semiconductor package substrate can be maintained by the dummy conductive protrusion B3 even in the frame state.

  FIG. 5I is a cross-sectional view in which a semiconductor chip is mounted after the outer shape is processed into a frame shape. First, after the die bonding film 18 was temporarily attached to the semiconductor package substrate, the semiconductor chip 17 (size 8.6 mm × 8.6 mm) was mounted while being heated and pressurized. Next, wire bonding (gold wire 16) was performed and connected to the bonding pads of the semiconductor chip 17 and the bonding pads of the wiring board using a wire bonder HW2100 (manufactured by Kyushu Matsushita Electric Co., Ltd.). Further, a transfer mold 19 was applied to seal the chip and the substrate for the semiconductor package. Next, a solder ball was placed on a ball pad (exposed conductive protrusion 2) to which a flux was previously applied on a semiconductor package substrate, and heat soldering was performed in a reflow furnace to form a solder bump 15. Finally, as shown in FIG. 5 (j), the semiconductor device 21 was manufactured by cutting it into a predetermined size (size 12 mm × 12 mm) with a dicing machine.

  As described above, as shown in the examples, the wiring member and the semiconductor package substrate were not damaged at all, such as wrinkles and blurring, and the semiconductor device could be manufactured efficiently.

The top view of the example of the uneven | corrugated shape of the dam (a)-(d) and electroconductive protrusion (e)-(h) of the wiring member of this invention. The top view of the flame | frame part by the wiring member of this invention. The top view of the flame | frame by the wiring member of this invention. The top view of the example of the shape and arrangement | sequence of the dummy electroconductive protrusion B of the wiring member of this invention. Sectional drawing of the manufacturing process of the wiring member of this invention, and a board | substrate for semiconductor packages. The top view of the panel from which many frame parts were taken.

Explanation of symbols

1. Dam 2. Conductive protrusion A
3. Dummy conductive protrusion B
4). Conductive protrusion C for through hole
5. Conductive protrusion D for slit hole
6). Panel 7. Frame part 8. Solder resist9. Third layer circuit 10. First metal layer 11. Second metal layer 12. Third metal layer 13. Reinforcing tape 14. Insulating resin 15. Solder bump (solder ball)
16. Gold wire 17. Semiconductor chip 18. Die bonding film 19. Sealant (transfer mold)
20. Through hole 21. Semiconductor device 22. flame

Claims (9)

  In a method for manufacturing a wiring member in which a plurality of conductive protrusions are formed on the surface of a metal layer, a multilayer metal foil having at least three layers of a first metal layer, a second metal layer, and a third metal layer in this order is prepared. Forming a conductive protrusion by removing the metal layer until the second or third metal layer is exposed, leaving a portion to be a conductive protrusion, and a portion requiring an insulating resin for embedding the conductive protrusion. A method for manufacturing a wiring member including a step of forming a dam on the surface of a metal layer along an outer periphery. 2. The method for manufacturing a wiring member according to claim 1 , wherein the step of forming a dam is a step of forming the dam by removing the metal layer until the second or third metal layer is exposed, leaving a portion to become the dam. . Forming a conductive projection method of the the wiring member according to claim 1 or 2 surface contacting the surface of the metal layer is a step of forming a conductive protrusion is uneven. The method for producing a wiring member according to any one of claims 1 to 3 , wherein the step of forming a dam is a step of forming a dam having a concave-convex shape on a surface in contact with the metal layer surface. Before the step of forming the conductive protrusion by removing the metal layer until the second or third metal layer is exposed leaving the portion to be the conductive protrusion, the opposite surface of the metal layer surface on which the conductive protrusion is formed process for the preparation of a wiring member according to any one of claims 1 to 4 including the step of attaching a tape for reinforcement. Before the step of forming the conductive protrusion by removing the metal layer until the second or third metal layer is exposed leaving the portion to be the conductive protrusion, the opposite surface of the metal layer surface on which the conductive protrusion is formed process for the preparation of a wiring member according to any one of claims 1 to 4, comprising the step of applying the resin for reinforcement. After the step of removing the metal layer and forming the conductive protrusions until the second or third metal layer is exposed, leaving the portion that becomes the conductive protrusions, the step of embedding the conductive protrusions with an insulating resin, A step of curing, a step of removing the second or third metal layer corresponding to the holding layer of a part of the conductive protrusions, and a step of removing the conductive protrusions after removing the second or third metal layer corresponding to the holding layer. The manufacturing method of the wiring member described in any one of Claims 1-6 . The method for manufacturing a wiring member according to claim 7 , wherein the step of removing the conductive protrusion is a step of removing the conductive protrusion by etching. 8. The wiring member manufacturing method according to claim 7 , wherein the step of removing the conductive protrusion is a step of removing the conductive protrusion by applying a force to one surface of the conductive protrusion exposed from the insulating resin to push out the conductive protrusion. Method.

Images