JP4549693B2 - Wiring board manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a wiring board having no core substrate.

  In recent years, due to the demand for higher functionality and lighter, thinner and smaller electronic devices, high-density integration has rapidly progressed in electronic components such as IC chips and LSIs. There is a demand for higher-density wiring and multi-terminals than ever before.

  As such a package substrate, a build-up multilayer wiring substrate is currently used. The build-up multilayer wiring board uses a rigid property of an insulating core substrate (glass epoxy substrate such as FR-4) in which a reinforcing fiber is impregnated with a resin, and is made of a polymer material on both main surfaces thereof. A build-up layer in which dielectric layers and conductor layers are alternately arranged is formed. In such a build-up multilayer wiring board, high-density wiring is realized in the build-up layer, while the core board plays a reinforcing role. For this reason, the core substrate is configured to be very thick compared to the build-up layer, and the wiring (called a through-hole conductor) for establishing electrical conduction between the build-up layers arranged on the respective main surfaces is thick inside the core substrate. It penetrates in the vertical direction. However, at the present time when the signal frequency to be used has become a high frequency band exceeding 1 GHz, there is a problem that the wiring penetrating such a thick core substrate contributes as a large inductance.

  Therefore, in order to solve such a problem, there has been proposed a wiring board mainly composed of a build-up layer that does not have a core board and can be formed with high density wiring, as shown in Patent Document 1. In such a wiring board, since the core board is omitted, the entire wiring length is short, which is suitable for high-frequency applications. In order to manufacture such a wiring board, as described in paragraphs 0012 to 0029 and FIGS. 1 to 4 of Patent Document 1, after forming a build-up layer on the metal plate, the metal plate is etched. By doing so, only the thin film build-up layer is obtained. This build-up layer is used as a wiring board.

JP 2002-26171 A

  However, in the case of the manufacturing method described in Patent Document 1, the metal plate on which the build-up layer is formed has a thickness that can play a reinforcing role at the time of manufacturing (for example, 0.8 mm in the case of a copper plate). However, it takes too much time (for example, about 30 minutes for a copper plate of 0.8 mm) to etch all of the build-up layer after forming it. there were.

  Therefore, the present invention has an object to provide a manufacturing method capable of easily obtaining a wiring substrate in which dielectric layers and conductor layers made of a polymer material are alternately laminated without having a core substrate. To do.

Means for solving the problems / effects of the invention

In order to solve the above problems, in the method for manufacturing a wiring board of the present invention,
A method of manufacturing a wiring board in which dielectric layers and conductor layers are alternately laminated,
On the main surface of the underlying dielectric sheet formed on the support substrate , a metal pad for external connection in the wiring board is disposed so as to be included in the main surface and a metal foil made of a material different from the metal pad. And while performing a metal pad placement step of placing through a metal foil adhesion body composed of a base portion in close contact with the metal foil,
In order to form a laminated sheet body having a wiring laminated portion to be the wiring board in the region on the metal foil on the base dielectric sheet,
A first dielectric that encloses the metal pad and the metal foil adhesion body and encloses the metal pad and the metal foil adhesion body by being in close contact with the base dielectric sheet in a peripheral region of the metal foil adhesion body. A first dielectric sheet forming step of forming a body sheet;
Forming a first conductor, wherein a first via conductor connected to the metal pad is formed through the first dielectric sheet, and a first conductor layer connected to the first via conductor is formed on the first dielectric sheet. Process,
A residual layer lamination step of laminating the remaining dielectric sheet, via conductor and conductor layer to be the laminated sheet body on the first dielectric sheet;
In this order, then
Removing the periphery of the laminated sheet body to expose the end of the metal foil;
A wiring laminated part peeling step for separating the wiring laminated part from the support substrate in a state where the metal foil is adhered at an interface between the metal foil and the base part,
A metal foil removing step of exposing the metal pad by etching away the metal foil attached to the wiring laminated portion;
Are performed in this order.
In this case, the base portion may be configured by laminating an adhesive layer and a base layer in this order from the metal foil side .
In addition, the peripheral portion of the laminated sheet body to be removed may include the vicinity of the outer edge of the metal foil adhesion body, and the laminated sheet body includes an individual corresponding to one wiring board. It is also possible to include a plurality.
Furthermore, in the step of forming the laminated sheet body, the metal foil adhesion body can be arranged on the base dielectric sheet in a semi-cured state.

  According to the present invention, the method for manufacturing a wiring board according to the present invention will be briefly described with reference to FIG. 1. (a) A base formed on a support substrate 20 (corresponding to a metal plate in Patent Document 1). A laminated sheet body 10 having a wiring laminated portion 100 (see FIG. 2) to be a wiring substrate is formed on the dielectric sheet 21, and (b) a peripheral portion (in the drawing) of the wiring laminated portion 100 in the laminated sheet body 10. The end surface 103 of the wiring laminated portion 100 is exposed to remove (c) the wiring laminated portion 100 from the support substrate 20 (and the underlying dielectric sheet 21). As described above, the wiring substrate can be easily obtained by separating the wiring laminated portion and the supporting substrate by peeling. In addition, since the wiring laminated portion and the support substrate are not separated by etching, a laminated sheet body can be formed on both main surfaces of the support substrate, which enables mass production of the wiring substrate.

  Hereinafter, detailed description will be given with respect to each step of FIG. In FIG. 1A, a laminated sheet body 10 having a wiring laminated portion 100 (see FIG. 2; details will be described later) to be a wiring board is formed on a base dielectric sheet 21 formed on a support substrate 20. ing. In the laminated sheet body 10, the metal foil adhesion body 5 in which the metal foil 5 b (upper side) is in close contact with the base portion 5 a (lower side) is disposed so as to be included in the main surface of the base dielectric sheet 21. A metal pad 5p for external connection on the wiring board is arranged. And the 1st dielectric sheet 11 is formed so that they may be wrapped. The first dielectric sheet 11 is in close contact with the metal pad 5p and the metal foil contact body 5 (metal foil 5b), and is in close contact with the base dielectric sheet 21 in the peripheral region 21c of the metal foil contact body 5, Thus, the metal pad 5p and the metal foil adhesion body 5 are sealed in the first dielectric sheet 11.

  Thus, the metal pad 5p and the metal foil adhesion body 5 are sealed by the first dielectric sheet 11, so that the interface between the metal foil adhesion body 5 (base part 5a) and the base dielectric sheet 21 is swollen or peeled off. The laminated sheet body 10 can be formed without this occurring. Then, in FIG. 1B, since the peripheral region 21c where the first dielectric sheet 11 and the base dielectric sheet 21 are in close contact with each other is removed, in FIG. It becomes possible to easily peel off the wiring laminated portion 100 at the interface. That is, with this configuration, formation of a laminated sheet body that requires adhesion (FIG. 1 (a)) and separation of a wiring laminate portion that requires ease of peeling (FIG. 1 (c)). Both can be performed satisfactorily.

  As shown in FIG. 2, a region on the metal foil 5 b in the laminated sheet body 10 is a wiring laminated portion 100. The wiring laminated portion 100 is obtained in a state where the metal foil 5b is adhered by the peeling of FIG. 1 (c), and is to be a wiring substrate thereafter by removing the metal foil 5b. In other words, it has a structure in which dielectric layers and conductor layers made of a polymer material are alternately laminated so as not to have a core substrate and both main surfaces are composed of dielectric layers (detailed structure) Will be described later).

  Moreover, the form of the lamination sheet body 10 should just have the wiring lamination | stacking part 100 (area | region on the metal foil contact | adherence body 5), and is not limited to the form of Fig.1 (a). For example, as shown in FIG. 3A, a configuration in which the dielectric sheets 111 and 112 are arranged on the metal foil adhesion body 5 and the first dielectric sheet 11 is sealed together may be employed. In this case, the via conductor formed on the lowermost dielectric sheet 111 and connected to the metal pad 5p is used as the first via conductor 41, and the conductor layer formed on the first dielectric sheet 11 is used as the first via conductor 41. As the conductor layer 31, a conductor layer and a via conductor are formed therebetween. Further, as shown in FIG. 3B, another dielectric sheet formed on the first dielectric sheet 11 may be configured only by a portion that becomes the wiring laminated portion 100.

  Next, in FIG.1 (b), the surrounding part (dashed line part in a figure) of the wiring lamination | stacking part 100 is removed among the lamination sheet bodies 10, and the end surface 103 of this wiring lamination | stacking part 100 is exposed. That is, the peripheral region 21c where the first dielectric sheet 11 and the base dielectric sheet 21 are in close contact with each other is removed, and the end face of the metal foil adhesive body 5 is exposed. Thereby, as shown in FIG. 1C, the wiring laminated portion 100 is easily peeled from the support substrate 20 at the interface of the metal foil adhesion body 5 (that is, the interface between the base portion 5a and the metal foil 5b). Can do. When removing the peripheral portion (broken line portion in the drawing) of the wiring laminated portion 100 in the laminated sheet body 10, the region under the peripheral portion of the support substrate 20 and the base dielectric sheet 21 is also removed together with the peripheral portion. By doing so, the end surface 103 of the wiring laminated portion 100 can be easily exposed.

  Further, in FIG. 1B, when the peripheral portion of the wiring laminated portion 100 is removed, the peripheral region 21c where the first dielectric sheet 11 and the base dielectric sheet 21 are in close contact is removed, and the metal foil adhesive body 5 is removed. As shown in FIGS. 4 (a) and 4 (b), it is possible to peel the wiring laminated portion 100 by exposing the end portion of the metal foil. The wiring laminated portion 100 is constituted by a region on a portion excluding the vicinity of the outer edge of the metal foil adhesion body 5, and the surrounding area is removed, that is, the vicinity of the outer edge of the metal foil adhesion body 5 is also removed. Can do.

  Next, the laminated sheet body 10 has the metal pad 5p, and the first dielectric sheet 11 includes the first via conductor 31 connected to the metal pad 5p and the first conductor layer 41 connected thereto. Therefore, in the wiring laminated body 100 to which the metal foil 5b shown in FIG. 1C is attached, when the metal foil 5b is removed, for example, as shown in FIG. 10, the metal pad 5p appears on the surface after the removal. With this configuration, the metal pad 5p can be used as a part of the terminal as it is, and operations such as perforation for forming a pad and formation of a conductor for the thin and soft wiring laminated portion 100 after peeling. Since it is no longer necessary to carry out the manufacturing, the manufacturing becomes easy.

  Further, the metal pad 5p and the metal foil 5b are made of different materials, and only the attached metal foil 5b can be selectively removed by etching after the wiring laminated portion 100 is peeled off. As a result, the metal pad 5 p is exposed on the main surface of the wiring laminated portion 100. For such selective etching removal, for example, the metal pad 5p (and other via conductors and conductor layers) is made of Cu, and the metal foil 5b is made of Ti (titanium), Ag (silver), Sn (tin). ), Al (aluminum), or one or more of them can be realized.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 5 is a diagram showing an outline of a cross-sectional structure of the wiring board 1 obtained by the method for manufacturing a wiring board of the present invention. The wiring substrate 1 has a structure in which dielectric layers (B1 to B3, SR) made of a polymer material and conductor layers (M1, M2, PD) are alternately stacked. The first main surface MP1 is a mounting surface for mounting an electronic component, and the first dielectric layer B1 forming the main surface has a protruding shape made of a well-known solder for connecting to the electronic component. Metal terminals (solder bumps) FB are formed. This metal terminal (solder bump) FB is connected to a metal pad (bump pad) BP provided below the first main surface. The second main surface MP2 is a connection surface for connecting to an external substrate, and an opening is formed in the dielectric layer (solder resist layer) SR forming the main surface, and the external substrate is in the opening. A metal terminal (metal pad) PD for installing a solder ball (described later) that bears the connection to is exposed.

  A wiring CL is formed in the metal layers M1 and M2, and a via conductor VA connected to the wiring CL is embedded in the dielectric layers B1 to B3. An electrical conduction path (for example, from the solder bump FB and the metal pad BP to the metal terminal pad PD) is formed by the wiring CL and the via conductor VA. The dielectric layers B1 to B3, SR can be made of, for example, a material mainly composed of an epoxy resin, and the wiring CL, the via conductor VA, the metal pad (bump pad) BP, and the metal terminal (pad). ) PD can be made of, for example, a material mainly composed of copper. Further, the surface of the metal pad (bump pad) BP or the metal terminal (pad) PD can be subjected to surface plating by, for example, Ni—Au plating.

  In the wiring board 1 as described above, as shown in FIG. 6, solder balls SB for connecting to an external board are installed on the metal terminals (pads) PD of the second main surface MP2, while the first main surface MP1. In addition, a reinforcing frame (stiffener) ST is installed, the electronic component IC is flip-chip connected to the solder bump FB, and the gap under the electronic component IC is filled with the underfill material UF. It becomes.

  Hereinafter, an example of the manufacturing method of the wiring board which is embodiment of this invention is demonstrated. 7-10 is a figure showing a manufacturing process. The step of forming the laminated sheet body 10 on the support substrate 20 shown in steps 1 to 6 can be performed by a known build-up method or the like.

  First, the metal pad placement step shown in steps 1 to 3 in FIG. 7 is performed. First, in step 1, a base dielectric sheet 21 is formed on a support substrate 20 for reinforcement during manufacturing. The support substrate 20 is not particularly limited as long as the underlying dielectric sheet 21 is in close contact with each other. For example, the support substrate 20 is composed of a glass epoxy substrate such as FR-4 (which is a material used for the core substrate as described above). be able to. Also, the base dielectric sheet 21 is not particularly limited, but can be made of, for example, the same material as the first dielectric sheet 11 described later, that is, a material mainly composed of epoxy.

Then, as shown in Steps 2 and 3, a metal pad 5p (metal pad BP in FIGS. 5 and 6) for external connection on the wiring board is different from the metal pad 5p on the main surface of the underlying dielectric sheet 21. It arrange | positions through the metal foil contact | adherence body 5 comprised by the metal foil 5b which consists of material, and the base part 5a which was distribute | arranged so that it might be included by the main surface, and was closely_contact | adhered to this metal foil 5b. The metal foil adhesion body 5 can be arranged on the semi-cured base dielectric sheet 21. Thereby, it becomes easy to obtain adhesiveness to such an extent that the metal foil adhesion body 5 (base part 5a) does not peel from the base dielectric sheet 21 in the subsequent steps. In addition, in the metal foil close_contact | adherence body 5, the metal foil 5b can be comprised by any 1 type or 2 types or more of Ti, Ag, Sn, and Al. The base part 5a can be comprised by metal foil, for example. In this case, the releasability is improved by using a material different from the metal foil 5b (for example, Cu or the like). Moreover, the base part 5a can also be comprised so that it may have the contact bonding layer 51 in an interface with the metal foil 5b, as shown in FIG. Specifically, the base portion 5 a can be composed of an adhesive layer 51 and a base layer 52. For example, by using a heat-peelable adhesive layer whose adhesive strength is reduced by heating, the later-described steps can be performed better.
Specifically, the metal pad placement step includes a multilayer sheet 5 having a base portion 5a, a metal foil 5b, and a pad metal layer 5c in this order as shown in Step 2, and the base portion 5a is a base dielectric. After arranging the sheet 21 so as to be on the main surface side, the metal pad 5p can be formed by selectively removing the pad metal layer 5c as shown in Step 3.

  Next, as shown in Steps 4 to 6 in FIG. 8, the laminated sheet body 10 having the wiring laminated portion 100 to be the wiring board in the region on the metal foil 5 b is formed on the base dielectric sheet 21. First, as shown in step 4, a first dielectric sheet forming step is performed in which the first dielectric sheet 11 is formed so as to wrap the metal pad 5p and the metal foil adhesion body 5. At this time, the first dielectric sheet 11 is in close contact with the base dielectric sheet 21 in the peripheral region of the metal foil adhesion body 5, thereby sealing the metal pad 5 p and the metal foil adhesion body 5. The dielectric sheet can be formed using, for example, a well-known vacuum lamination method.

  Then, as shown in step 5, the first via conductor 41 connected to the metal pad 5p is formed through the first dielectric sheet 11, and the first conductor layer 31 connected to the first via conductor 41 is formed as the first dielectric. A first conductor forming step for forming on the body sheet 11 is performed. The conductor layer can be formed by, for example, a known semi-additive method. The via conductor can be obtained, for example, by forming a via hole by a well-known photo via process and filling the via hole by electroless plating in the semi-additive method.

  Thereafter, as shown in step 6, a remaining layer stacking step is performed in which the remaining dielectric sheet, via conductors, and conductor layers to be the stacked sheet 10 are stacked on the first dielectric sheet 11. Specifically, the second dielectric sheet 12 is formed on the first dielectric sheet 11, the via conductor 42 is formed through the second dielectric sheet 12, and the second dielectric sheet 12 is formed on the second dielectric sheet 12. A two-conductor layer 32 is formed. And the same process is repeated and the dielectric sheets 13 and 14, the via conductor 43, and the conductor layer 33 are formed, and the lamination sheet body 10 as shown to the process 6 is formed. In addition, in this embodiment, although the lamination sheet body 10 is comprised by the metal foil adhesion body 5 and the dielectric sheet 11-14 of 4 layers, the number of layers of a dielectric sheet is not restricted to this. .

  The dielectric sheets 11 to 14 can be made of a material mainly composed of epoxy. Further, the conductor layers 31 to 33 and the via conductors 41 to 43 can be composed mainly of Cu (copper).

  In the present embodiment, the exposed main surface on the upper side of the laminated sheet body 10 is formed to be the second main surface MP2 of the wiring board 1 shown in FIG. Therefore, the dielectric sheet 14 forming the upper main surface of the laminated sheet body 10 corresponds to the solder resist layer SR of the wiring board 1 in FIG. 5, and the conductor layer 33 exposed in the opening 14a is the wiring layer in FIG. This corresponds to the metal terminal (pad) PD of the substrate 1. On the other hand, the upper main surface may be the first main surface MP1 of the wiring board 1 shown in FIG. In that case, the metal pad 5p corresponds to the metal terminal (pad) PD of the wiring board 1 of FIG. Further, the solder bump FB shown in FIG. 5 is formed on the dielectric sheet 14 forming the upper main surface.

  The laminated sheet body 10 obtained by the above steps is formed so that the region on the metal foil adhesion body 5 becomes the wiring laminated portion 100 to be the wiring substrate 1 (see FIG. 5). Therefore, as shown in Steps 7 and 8 in FIG. 9, a peripheral region removing step for exposing the end surface of the wiring laminated portion 100 is performed by removing the peripheral region of the wiring laminated portion 100 in the laminated sheet body 10. At this time, at the boundary between the wiring laminated portion 100 and the peripheral portion, the underlying dielectric sheet 21 and the support substrate 20 thereunder are cut by, for example, a blade blade. As described above, when the region under the peripheral portion of the support substrate 20 and the base dielectric sheet 21 is removed together with the peripheral region of the wiring laminated portion 100, the end face is easily exposed.

  Next, as shown in Step 9, the wiring laminated portion 100 is peeled from the support substrate 20 with the metal foil 5b attached at the interface between the metal foil 5b and the base portion 5a. . Then, as shown in step 10 of FIG. 10, a metal foil removing step is performed in which the metal foil 5b attached to the wiring laminated portion 100 is removed by etching to expose the metal pad 5p. Then, as shown in step 11, metal terminals 8 (solder bumps FB in the wiring substrate 1 of FIG. 5) are formed on the metal pads 5p. Thereby, the wiring board 1 shown in FIG. 5 is obtained.

  In step 10, the metal foil 5b can be removed by chemical etching. A metal pad 5p appears on the main surface of the first dielectric sheet 1 'from which the metal foil 5b has been removed. In step 11, the metal terminal 8 is connected to the metal pad 5p. In this way, by configuring the metal pad 5p to be positioned on the main surface of the first dielectric sheet 11 ′, the metal terminals (solder bumps) 8 can be easily formed and connection reliability can be ensured. In the present embodiment, the conductor layers 31 to 33 and the via conductors 41 to 43 are made of Cu, and the conductor layer 33 (metal pad PD) exposed on the opposite main surface is also made of a material different from that of the metal foil 5b. Therefore, the metal foil 5b can be removed without masking the opposite main surface, and the process becomes simple.

  In the above manufacturing process, as shown in FIG. 11, the wiring laminated portion 100 included in the laminated sheet body 10 is formed by connecting a plurality of individual 100 ′ corresponding to one wiring board, that is, the wiring board 1. It can be configured as a multi-piece work substrate.

The figure which shows simply the process of the manufacturing method of the wiring board of this invention. The figure which shows the wiring lamination sheet body 100 contained in the lamination sheet body 10 The figure showing the modification of the lamination sheet body 10 Modified example of the region to be the wiring laminated portion 100 in the laminated sheet body 10 The figure showing the outline of the cross-sectional structure of the wiring board which is one Embodiment of this invention Semiconductor device using wiring board 1 of FIG. The figure showing the process of the manufacturing method of the wiring board which is one Embodiment of this invention Figure following Figure 7 Figure following Figure 8 Figure following Figure 9 The figure which looked at the wiring lamination | stacking part 100 made into the multi-piece work substrate from the upper part The figure showing the outline of the section structure in the modification of a metal foil adhesion object

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wiring board 5 Metal foil adhesion body 5b Metal foil 5p Metal pad 10 Laminated sheet body 11 1st dielectric sheet 20 Support substrate 21 Base dielectric sheet 100 Wiring laminated sheet body

Claims (5)

A method of manufacturing a wiring board in which dielectric layers and conductor layers are alternately laminated,
On the main surface of the underlying dielectric sheet formed on the support substrate , a metal pad for external connection in the wiring board is disposed so as to be included in the main surface and a metal foil made of a material different from the metal pad. And while performing a metal pad placement step of placing through a metal foil adhesion body composed of a base portion in close contact with the metal foil,
In order to form a laminated sheet body having a wiring laminated portion to be the wiring board in the region on the metal foil on the base dielectric sheet,
A first dielectric that encloses the metal pad and the metal foil adhesion body and encloses the metal pad and the metal foil adhesion body by being in close contact with the base dielectric sheet in a peripheral region of the metal foil adhesion body. A first dielectric sheet forming step of forming a body sheet;
Forming a first conductor, wherein a first via conductor connected to the metal pad is formed through the first dielectric sheet, and a first conductor layer connected to the first via conductor is formed on the first dielectric sheet. Process,
A residual layer lamination step of laminating the remaining dielectric sheet, via conductor and conductor layer to be the laminated sheet body on the first dielectric sheet;
In this order, then
Removing the periphery of the laminated sheet body to expose the end of the metal foil;
A wiring laminated part peeling step for separating the wiring laminated part from the support substrate in a state where the metal foil is adhered at an interface between the metal foil and the base part,
A metal foil removing step of exposing the metal pad by etching away the metal foil attached to the wiring laminated portion;
A method of manufacturing a wiring board, wherein the steps are performed in this order. The method for manufacturing a wiring board according to claim 1, wherein the base portion is configured by laminating an adhesive layer and a base layer in this order from the metal foil side . The method for manufacturing a wiring board according to claim 1 , wherein the peripheral portion of the laminated sheet body to be removed includes a vicinity of an outer edge of the metal foil adhesion body. The method for manufacturing a wiring board according to any one of claims 1 to 3 , wherein the laminated sheet body includes a plurality of individuals corresponding to one wiring board. 5. The wiring according to claim 1 , wherein in the step of forming the laminated sheet body, the metal foil adhesion body is disposed on the base dielectric sheet in a semi-cured state. A method for manufacturing a substrate.

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