JP2005136361A - Manufacturing method of wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the connectability of a metal bump 12 with a metal layer 14 or a wiring layer 14d connected on the top face 12a from being deteriorated by accumulating a residue made of an epoxy resin 4 of stage B in a polishing groove (polishing scratch) generated on the top face 12a of the metal bump 12 in a step for polishing the epoxy resin 4 formed on the surface of the metal bump 12 formation side of a metal plate 2 until the top face 12a of the metal bump 12 is exposed, to polish also by wet polishing, and to carry out a smooth and highly efficient polish. <P>SOLUTION: The manufacturing method has a step for forming an epoxy resin 4 of stage B having a thickness covering metal bumps 12 entirely on the surface of a metal plate 2 where the metal bumps 12 for interlayer connection are formed on one surface; and a step for pressurizing and heating the epoxy resin 4 so as to be stage C and a stage for wet polishing the front surface of an interlayer insulating film 4 made of an epoxy resin become stage C until the top face 12a of each metal bump 12 is exposed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method of manufacturing a wiring board using metal bumps as interlayer connection means.

The applicant company of the present application has developed various techniques for manufacturing a multilayer wiring board, and many of the developed techniques are techniques using metal bumps as interlayer connection means. As a specific example of the technique, an etching barrier layer (thickness, for example, 1 μm) made of nickel, for example, is formed on one main surface of a copper layer for bump formation (thickness, for example, 100 μm). A wiring circuit board forming member made of a metal plate having a three-layer structure in which a copper foil (thickness, for example, 18 μm) for forming a conductor circuit is formed on the main surface is used as a base, and the surface is processed, for example, between layers A wiring board having bumps which are fine projections for connection is obtained. For example, Japanese Patent Application No. 2000-230142 (Japanese Patent Application Laid-Open No. 2002-4350) relates to this.
No. 6), Japanese Patent Application No. 2000-334332 (Japanese Patent Laid-Open No. 2002-141629),
A technical proposal was made by filing an application such as Japanese Patent Application No. 2002-66410 (Japanese Patent Laid-Open No. 2002-43506).

7A to 7E are cross-sectional views showing a typical example of a method of manufacturing a wiring board using such a technique in the order of steps.
(A) As shown in FIG. 7A, a metal plate 102 having a metal bump formed on one surface is prepared, and further, for example, a glass cloth or a glass mat in a B-stage state is used as a base material. The laminated body of the B stage resin 104 and the release sheet 106 made of epoxy resin is exposed.
The metal plate 102 has bumps 11 made of, for example, copper on one surface of a wiring film forming metal film 108 made of, for example, copper via an etching barrier metal layer 110 made of, for example, nickel.
2 is formed.

The metal plate 102 is formed, for example, by forming an etching barrier layer (thickness, for example, 1 μm) made of nickel, for example, on one main surface of a copper layer for bump formation (thickness, for example, 100 μm). A metal plate having a three-layer structure in which a copper foil (thickness, for example, 18 μm) for forming a conductor circuit is formed on the main surface of the barrier layer is used as a wiring board forming member, and the bump forming copper layer is selectively etched. Then, the metal bump 112 is formed, and then the etching barrier layer 110 made of nickel, which has functioned as an etching stopper at the time of etching, is removed by etching using the metal bump 112 as a mask.

With regard to this method, for example, Japanese Patent Application No. 2000-230142 (Japanese Patent Application Laid-Open No. 2002-4350).
No. 6), Japanese Patent Application No. 2000-334332 (Japanese Patent Laid-Open No. 2002-141629),
Technical proposals have been made by filing applications such as Japanese Patent Application No. 2002-66410 (Japanese Patent Laid-Open No. 2002-43506).
The resin 104 serves as an interlayer insulating film, has a sheet shape, and is made of an epoxy resin in a B-stage state. Reference numeral 106 denotes a release sheet which is superimposed on the epoxy resin 104.

When the resin 104 is formed on the bump forming surface side of the metal plate 102, the release sheet 106 appropriately protrudes the top of the metal bump 112 from the surface of the resin 104, and is laminated by pressurization and heating. This is to secure a shrinkage allowance in anticipation of the bump 112 being shrunk, and is to be peeled after the top surface is polished and the top surface of the metal bump 112 is exposed, and the resin 104 in the B stage state. It also serves to prevent contamination of the surface.
Although not shown, a cushion material is disposed on the laminate made of the release sheet 106 and the B stage resin 104, and the laminate is a metal plate via a pressure plate (not shown). The bump 102 is pressed and heated on the bump forming surface side. The heating temperature at this time is set to a temperature of 120 ° C. or lower so as to maintain the B stage state. FIG. 7A shows the metal plate 102 and the laminate composed of the release sheet 106 and the resin 104 in a state immediately before being pressurized and heated.

(B) When a laminate composed of the resin 104 and the release sheet 106 is laminated on the bump forming surface side of the metal plate 102 by pressurization and heating, the result is as shown in FIG.
(C) Next, as shown in FIG. 7C, the laminate composed of the resin 104 and the release sheet 106 is dry-polished until the top surface 112a of each metal bump 112 is exposed. Dry polishing is polishing performed without supplying a cooling liquid such as water to the polishing portion. The reason why the wet polishing, that is, the polishing performed while supplying the cooling liquid such as water to the polishing portion is not performed is that the resin 104 gradually deteriorates due to the liquid such as moisture entering the B-stage resin 104, and the resin 104 This is to avoid the loss of the original resin physical properties.

(D) Next, as shown in FIG. 7D, the release sheet 106 is peeled off and removed.
(E) Next, as shown in FIG. 7E, a metal layer 114 made of, for example, copper is applied to the resin 10.
4 and the surface of the metal bump 112, and the metal layer 114 and the metal bump 112 are firmly and satisfactorily connected to each other by a powerful press (pressure is, for example, 5.0 to 10.0 MPa). As a result, the metal bump 112 shrinks, for example, by about 30%. Then, while maintaining the pressed state, the resin 104 is heated to 170 to 220 ° C. to change the resin 104 to a C-stage state to form an interlayer insulating film.
Thereafter, although not shown, the metal layers 108 and 114 are patterned by selective etching to form a wiring film.
JP 2002-43506 A (Japanese Patent Application No. 2000-230142) JP 2002-141629 A (Japanese Patent Application No. 2000-334332) JP 2002-43506 A (Japanese Patent Application No. 2002-66410)

By the way, according to the above-described conventional technique, as shown in FIGS. 8A and 8B, fine polishing grooves (polishing scratches) 120 that are inevitably generated by the abrasive grains of the polishing grindstone by the polishing. Inside, a resin residue 122 due to the resin 104 in the B-stage state is accumulated, and this is the metal bump 112.
There is a problem that it may cause a risk of reducing good electrical connectivity between the metal layer 114 and the metal layer 114 connected thereto.

Therefore, the inventors of the present invention have investigated the cause of the problem, and in the polishing step of polishing the laminate of the resin 104 and the release sheet 106 until the top surface 112a of the metal bump 112 is exposed, the resin 104 is a B stage. In the dry polishing method, the resin is easily liquefied by frictional heat, enters the polishing groove 120 in the B stage state, and is a residue. As it turned out to remain.
The present inventor therefore obtained the idea of avoiding such a problem by making the B stage state resin called prepreg at the time of polishing into a C stage state in which 104 is completely solidified, Further exploration continued to achieve the present invention.

That is, the present invention provides polishing that occurs on the top surface of the metal bump in a polishing step in which a resin such as epoxy resin formed on the surface of the metal plate on which the metal bump is formed is polished until the top surface of the metal bump is exposed. Residues made of B-stage, that is, liquefied resin, accumulate in the grooves (polishing scratches), and the residue may impair the connectivity between the metal bumps and the metal layer or wiring layer connected at the top surface. It is intended to prevent the occurrence of the occurrence, and to be able to perform the polishing in the polishing step while suppressing temperature rise by wet polishing, so that smooth and highly efficient polishing can be performed. Furthermore, it is intended to increase the peeling strength between the metal insulating layer formed on the interlayer insulating film made of the resin and the wiring bump forming metal layer formed so as to be connected to the top surface of the metal bumps. To.

The method of manufacturing a wiring board according to claim 1 is a thickness that completely covers the metal bump, which serves as an interlayer insulating film, on the one surface of the metal plate in which the metal bump for interlayer connection is formed on one surface. Forming a B-stage resin and pressurizing and heating the resin to form a C-stage to form an interlayer insulating film, and the surface of the interlayer insulating film made of the C-stage resin to each of the above-mentioned It has the process of carrying out wet polishing until the top surface of a metal bump is exposed.

The method for manufacturing a wiring board according to claim 2 is the method for manufacturing a wiring board according to claim 1, wherein after the wet polishing step, a metal is formed on the surface of the prepreg of the C stage and the top surface of the metal bump. The layer is formed by plating.
The method for manufacturing a wiring board according to claim 3 is the method for manufacturing a wiring board according to claim 2, wherein the metal layer for forming the wiring film is formed by plating, first, a metal plating layer is formed by electroless plating, Further, it is characterized in that it is performed by forming a metal plating layer thicker than the metal plating layer by electroless plating by electrolytic plating.
The method for manufacturing a wiring board according to claim 4 is the method for manufacturing a wiring board according to claim 2 or 3, wherein the metal layer is formed on the surface of the prepreg of the C stage and the top surface of the metal bump by plating. And a step of forming a mask film having a negative pattern with respect to the pattern of the wiring film to be formed.

In the method for manufacturing a wiring board according to claim 5, an interlayer insulating film is formed on the roughened surface of the metal layer whose one surface is roughened by electrolytic treatment, and the thickness is smaller than the height of the metal bump described later. The B-stage resin layer is laminated, and the laminate of the metal layer and the resin layer is formed on the one surface of the metal plate for wiring film formation in which metal bumps for interlayer connection are formed on one surface. With the resin layer facing the surface, the resin layer is laminated by pressing and heating to make the resin layer a C stage, and then the top surface of the second metal bump is placed on the metal layer and the resin layer. The wet polishing is performed until the other surface of the metal layer is exposed.
The method for manufacturing a wiring board according to claim 6 is the method for manufacturing a wiring board according to claim 5, wherein after the polishing is finished, the one surface of the metal plate for wiring film formation is subjected to electroless plating and electrolytic plating. A metal layer for forming a wiring film in contact with each metal bump at the top surface is formed.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a wiring board, comprising: a metal plate for forming a wiring film having a metal bump for interlayer connection formed on one surface; Forming a B-stage resin having a thickness to cover the resin, pressurizing and heating the resin so that it becomes a C-stage, and exposing the top surface of each of the metal bumps on the surface of the C-stage resin. A series of steps comprising: forming a patterned wiring film made of a metal layer on the surface of the resin of the C stage and the top surface of the metal bump after the step of wet polishing until the step of performing wet polishing; Thereafter, at least metal bumps connected to the wiring film are formed on the surface on which the wiring film is formed, and thereafter, the same steps as the above series of steps are repeated at least once. Characterized in that to obtain a wiring board having a plurality of stages of bumps.

The method for manufacturing a wiring board according to claim 8 includes: a wiring film formed on both surfaces of an interlayer insulating film; and a mask on both surfaces of the substrate having first metal bumps connecting the wiring films on both surfaces to the interlayer insulating film. A step of selectively forming a film, and a step of forming a second metal bump made of the metal and connected to the wiring film by forming a metal on both surfaces of the substrate using the mask film as a mask, and ,
Removing the mask film; forming a B-stage resin having a thickness covering the second metal bumps on both surfaces of the substrate; and applying the resin to the C-stage by pressing and heating; The method further comprises a step of polishing the resin of the C stage until a flat top surface is formed on the metal bump.

According to the method for manufacturing a wiring board according to claim 1, the B-stage resin serving as an interlayer insulating film is completely covered on the metal bump forming surface of the metal plate on which the metal bump is formed, and the metal bump is completely covered; The resin is pressurized and heated to become a C stage, and then the surface of the resin that has become the C stage is polished until the top surface of each metal bump is exposed. Resin residue in the B-stage state accumulates in the polishing groove (polishing scratch) generated on the top surface of the metal bump, which has been generated by polishing, and the connection between the metal bump and the metal layer or wiring layer connected on the top surface It is possible to avoid the problem that the performance is impaired.

In addition, although polishing scraps can be generated by the C-stage resin by polishing, as in the case of the conventional B-stage resin (prepreg), it is liquefied by frictional heat and clogged in the polishing groove (polishing scratches) as a resin residue, There is no possibility that the good connectivity between the top surface of the metal bump and the metal layer is impaired. Incidentally, the solidified resin can be easily removed by washing with a liquid such as air spray or water even if it enters a polishing groove (polishing scratch).
In addition, since the resin forming the interlayer insulating film has completely changed from the B-stage state to the C-stage state during polishing, the interlayer insulating film made of the resin may be deteriorated by supplying a cooling liquid such as water. Absent.
Therefore, wet polishing becomes possible, and as a result, polishing while cooling by wet polishing can be continued, and as a result, smooth and rapid polishing can be achieved.
Therefore, smoothing and speeding up of the polishing process can be achieved.

According to the method for manufacturing a wiring board according to claim 2, after the polishing in the method for manufacturing the wiring board according to claim 1, it is formed by plating for forming a metal layer on the resin surface and the metal bump top surface in the C stage state. Therefore, a wiring layer made of the metal layer can be obtained.
According to the method for manufacturing a wiring board according to claim 3, the plating is electrolessly plated, and then
Since the electroplating is performed, the base of the electroplating film that can be plated with high plating speed and high plating quality is formed by electroless plating, and after the base is formed, a metal layer by electroplating can be obtained. it can.
Therefore, a high-quality metal layer can be formed quickly and without any trouble.

According to the method for manufacturing a wiring board according to claim 4, since the mask film is formed before plating for forming the metal layer in the method for manufacturing a wiring board according to claims 2 and 3, the pattern of the mask film is used. On the other hand, a negative pattern wiring film can be obtained by plating.
Therefore, since the wiring film having a predetermined pattern can be formed by plating without using selective etching, a side etching is not generated, and a fine wiring film having a high degree of integration can be formed.

According to the method for manufacturing a wiring board according to claims 5 and 6, a B-stage resin layer serving as an interlayer insulating film is laminated on the roughened surface of the metal layer roughened by electrolytic treatment, and the metal Since the laminate of the layer and the resin layer is laminated by pressurizing and heating to make the resin layer a C-stage, the metal layer is electrolyzed for adhesion between the metal layer and the resin layer serving as an interlayer insulating film. The surface roughened by the treatment can be interposed. Therefore, the peeling strength is further increased.
Therefore, it is possible to provide a wiring substrate having a strong peeling strength with respect to the interlayer insulating film of the wiring film forming metal layer formed by electroless plating or electrolytic plating after the formation of the metal layer.

Incidentally, the resin residue in the B stage state is accumulated in a polishing groove (polishing scratch) generated on the top surface of the metal bump, which has been generated by polishing the resin in the B stage state in the past, and is connected to the metal bump and the top surface. The problem that the connectivity with the metal layer or the wiring layer is impaired can be avoided, and polishing scraps can also be produced by the C-stage resin by polishing,
Liquefied by frictional heat as in the case of conventional B-stage resin (prepreg),
There is no possibility of clogging the polishing groove (polishing scratch) as a resin residue and impairing the good connectivity between the top surface of the metal bump and the metal layer, and the solidified resin enters the polishing groove (polishing scratch) Also, it can be easily removed by washing with a liquid such as air spray or water, and is the same as the case of the method for manufacturing a wiring board according to claim 1.
In addition, since the resin forming the interlayer insulating film has completely changed from the B-stage state to the C-stage state during polishing, the interlayer insulating film made of the resin may be deteriorated by supplying a cooling liquid such as water. Therefore, wet polishing becomes possible, and as a result, polishing while cooling by wet polishing can be continued, so that smooth and quick polishing can be achieved. Therefore, the smoothing and speeding up of the polishing process can be achieved as in the case of the wiring board manufacturing method according to claim 1.

According to the method for manufacturing a wiring board according to claim 7, after forming the interlayer insulating film with the resin of the B stage where the metal bump top surface is exposed, the wiring film is formed, and then the metal bump is formed.
The process of forming the wiring film after the formation of the interlayer insulating film from the resin with the metal bump top surface exposed is repeated a plurality of times, so that a multilayered wiring board having a plurality of metal bumps can be obtained. This can be done by using techniques 6 to 6.

According to the method for manufacturing a wiring board according to claim 8, the first metal bump for interlayer connection is provided.
A mask film is selectively formed on both surfaces of a substrate having a wiring film formed on both sides, a second metal bump is formed by forming a metal using the mask film as a mask, and then the above-described claim 1.
Therefore, a wiring board having a large number of layers having metal bumps in multiple stages can be obtained.

In the present invention, as the prepreg, an epoxy resin containing glass cloth or an epoxy resin containing glass mat is suitable.
Further, the pressure applied when the prepreg is formed on the main surface of the metal plate on the metal bump forming side is preferably about 3 to 4 MPa, for example, and can be considerably lower than the conventional 5 to 10 MPa. This is because it is not necessary to connect the metal bump and the metal layer by applying pressure and heating strong enough to crush the metal bump.

Further, before forming the metal layer connected to the metal bump, the surface of the interlayer insulating film made of resin is preferably subjected to a roughening (roughening) process. This is because it can strengthen the adhesion of the metal layer to the interlayer insulating film by plating. For example, this treatment is applied to a treatment liquid such as potassium permanganate liquid, sodium dichromate liquid or concentrated alkaline liquid as shown in FIG.
) By immersing the entire metal plate 2 shown in FIG. 2), whereby the surface of the interlayer insulating film made of resin can be roughened.

In addition, by forming a metal layer serving as a base of a metal layer for forming a wiring film connected to a metal bump using an electrolytic metal foil in which a carrier foil made of copper or the like is laminated via an adhesive, an interlayer insulating film is used. Increasing the peeling strength of the wiring film forming metal layer is also a good embodiment. That is, an electrolytic copper foil with a peelable carrier foil in which an electrolytic copper foil having a roughened surface and fine-grained copper formed on the surface is bonded to a carrier copper foil via an organic agent is a printed wiring board In this regard, technological development is remarkable, and the result is, for example,
001-140091, etc., but can also be used in the present invention. This is because when a B-stage resin layer serving as an interlayer insulating film is laminated on the rough surface on which the fine-grained copper is formed, and then the resin layer is made C-stage by pressurization and heating, the interlayer insulating film is firmly formed. The electrolytic copper foil can be brought into a bonded state, and a wiring film forming metal layer having the electrolytic copper foil as a base can be formed.

It should be noted that the enhancement of the peeling strength by using the above roughening (roughening) treatment or the use of an electrolytic metal foil with a carrier foil is not essential to the present invention.
The metal layer connected to the metal bump can be formed by plating.
First, it is preferable to perform electroless plating to form a base film for forming an electrolytic plating film, and then perform electrolytic plating. However, the present invention is not necessarily limited thereto, and may be formed by other methods such as sputtering, vacuum deposition, and CVD (chemical vapor deposition).

Then, instead of forming the metal layer entirely, for example, after forming (nucleating) palladium particles that serve as a nucleating agent for electroless plating, a mask film made of, for example, a photoresist is formed. A patterned metal layer, that is, a wiring film can be formed by growing a metal layer by electroless plating as a mask or by subsequent electrolytic plating or the like. Of course, plating may be performed only by electrolytic plating instead of electroless plating, or a wiring film may be formed by sputtering, vacuum deposition, or CVD (chemical vapor deposition) other than plating. good.
Also, after forming the interlayer insulating film with a resin such as an epoxy resin with the metal bump top surface exposed, a wiring film is formed, and then a metal bump is formed, and then the metal bump top surface is exposed, such as an epoxy resin. It is also possible to obtain a multilayered wiring board having a plurality of metal bumps by repeating a process of forming an interlayer insulating film with the resin and then forming a wiring film a plurality of times.

Hereinafter, the present invention will be described in detail according to illustrated embodiments.
1A to 1G show the first embodiment of the method for manufacturing a wiring board according to the present invention in the order of steps (A) to (G).
FIG.
(A) As shown in FIG. 1 (A), a metal plate 2 having a metal bump formed on one surface is prepared, and further, for example, an epoxy resin 4 and a release sheet 6 in a B-stage state are provided on the surface. Let the laminate face. As this epoxy resin, an epoxy resin with glass cloth or an epoxy resin with glass mat is suitable. In the present embodiment and the second embodiment described below, the epoxy resin used includes an epoxy resin containing glass cloth or a glass mat.
The metal plate 2 is formed by forming bumps 12 made of, for example, copper on one surface of a wiring film forming metal film 8 made of, for example, copper via an etching barrier metal layer 10 made of, for example, nickel.

The metal plate 2 is formed, for example, by forming an etching barrier layer (thickness 1 μm, for example) made of nickel on one main surface of a bump forming copper layer (thickness 60 μm, for example) by electroless plating. A metal plate having a three-layer structure in which a conductive circuit forming copper foil (thickness, for example, 18 μm) is formed on the main surface of the etching barrier layer is used as a wiring board forming member, and the bump forming copper layer is selectively used. The metal bumps 12 are formed by etching, and then the etching barrier layer made of nickel, which has functioned as an etching stopper during the etching, is removed by etching using the metal bumps 12 as a mask. .

(B) When a laminate composed of the epoxy resin 4 and the release sheet 6 is laminated on the bump forming surface side of the metal plate 102 by pressurization and heating, the result is as shown in FIG. In this case, the pressure for pressurization for lamination is about 3 to 4 MPa, the heating temperature is 160 to 250 ° C., and the epoxy resin 4 is changed from the B stage to the C stage state. Thus, in the present invention, the epoxy resin 4 is changed from the B stage to the C stage state before polishing.
(C) Next, the release sheet 6 is peeled off, and then the exposed epoxy resin 4 is polished until the top surface 12a of each metal bump 12 is exposed. This polishing is performed by wet polishing, that is, polishing performed while supplying a cooling liquid such as water to the polishing portion. FIG. 1C shows a state after the polishing.

Polishing scraps can also be produced by the C-stage state by polishing, that is, completely solidified and cured epoxy resin 4 (which can function as an interlayer insulating film). There is no possibility that the (prepreg) clogs the polishing groove (polishing scratches) and remains as a resin residue, and the good connectivity between the top surface of the metal bump and the metal layer is impaired.
In addition, since the epoxy resin has already changed from the B stage state to the C stage state during polishing, even if a cooling liquid such as water is supplied, the interlayer insulating film made of the epoxy resin or the like is not likely to be deteriorated thereby. Therefore, the polishing can be performed by wet polishing. Further, the polishing by wet polishing can be performed while supplying a cooling liquid, for example, water, that is, while cooling, so that the polishing efficiency can be increased, and further, smooth polishing can be performed at high speed.

(D) Next, as shown in FIG. 1 (D), an epoxy resin (becomes a C-stage state and is sufficiently cured to form an interlayer insulating film. Is referred to as an “interlayer insulating film.”) The surface of 4 is roughened (roughened). This roughening is performed in order to enhance the adhesion of a metal layer to be formed later by plating to the interlayer insulating film. This treatment is performed by immersing the entire metal plate 2 in a treatment solution such as a potassium permanganate solution, a sodium dichromate solution or a concentrated alkali solution. As described above, this roughening (roughening) treatment is not indispensable.
(E) Next, as shown in FIG. 1E, an electroless plating film 14a made of, for example, copper (or nickel or tin) is formed on the surface of the epoxy resin 4 where the top surface 12a of the metal bump 12 is exposed. . This becomes a base of an electrolytic plating film (14b) made of, for example, copper, which is formed next.

(F) Next, an electrolytic plating film 14 b made of, for example, copper is formed on the surface of the electroless plating film 14. A wiring film forming metal film 14 is formed by the electroless plating film 14a and the electrolytic plating film 14b.
Is formed. FIG. 1F shows a state after the formation of the wiring film forming metal film 14.
(G) Next, as shown in FIG. 1G, the metal film 8 and the metal film 14 are patterned by selective etching, so that the wiring films 8a and 14d are formed on both surfaces of the interlayer insulating film 4 of the metal plate 2. Get.

According to this embodiment, the metal bump 12 is completely covered with the B-stage epoxy resin 4 serving as an interlayer insulating film on the metal bump forming surface of the metal plate 2 on which the metal bump 12 is formed,
Further, the epoxy resin 4 is pressurized and heated to become a C stage, and then the epoxy resin that has become the C stage, that is, the surface of the interlayer insulating film 4 is polished until the top surface of each metal bump 12 is exposed. As a result, the conventional problems described above can be solved.
Explaining the problem anew, the resin in the B stage state is clogged as a resin residue in the polishing groove (polishing scratch) generated on the top surface of the metal bump, which was generated by polishing the epoxy resin 4 in the B stage state. This is a problem that the connectivity between the bump and the metal layer or wiring layer connected at the top surface may be impaired. According to the present invention, this problem can be avoided reliably.

Polishing scraps can also be formed by the epoxy resin (interlayer insulating film) 4 in the C stage state by polishing. However, since it is polishing scraps from completely cured resin, the resin in the B stage state is polished into the polishing grooves (polishing scratches as in the prior art). ) And remains as a resin residue, and there is no fear that the good connectivity between the top surface of the metal bump and the metal layer is impaired.
Further, since the prepreg has already changed from the B stage state to the C stage state during polishing, the interlayer insulating film 4 made of epoxy resin is not likely to be deteriorated by supplying a cooling liquid such as water.
Therefore, wet polishing becomes possible, and as a result, polishing while cooling by wet polishing can be continued, and as a result, smooth and rapid polishing can be achieved.
Therefore, smoothing and speeding up of the polishing process can be achieved.

FIGS. 2A to 2F are cross-sectional views showing a second embodiment of the method for manufacturing a wiring board of the present invention in the order of steps.
(A) First, as shown to FIG. 2 (A), the electrolytic copper foil 60 with a peelable carrier copper foil is prepared. The electrolytic copper foil 60 with the carrier copper foil has a copper foil body portion in which one surface is roughened and fine copper particles are formed on the rough surface by electrolysis to increase the roughness (
The other surface of the thickness 62 (for example, about 3 μm) 62 is bonded to one surface of the carrier copper foil (for example, about 35 μm) 66 with an adhesive 64.
(B) Next, as shown in FIG. 2 (B), a B stage state in which an interlayer insulating film is formed on the surface (roughened surface) of the copper foil body portion 62 of the electrolytic copper foil 60 with the carrier copper foil. Epoxy resin 4
(Thickness is thinner than the height of the bump 12 described later. Glass cloth or glass mat may be included.)

(C) Next, the carrier copper foil 66 of the electrolytic copper foil 60 with the carrier copper foil is peeled off, and the remaining copper foil main body (hereinafter, this copper foil main body is simply referred to as “electrolytic copper foil”) 60 and B. The adhesive body with the epoxy resin 4 in the stage state is placed above the surface on the metal bump 12 formation side of the same metal plate 2 as the metal plate 2 shown in FIG. 1A, with the epoxy resin 4 side facing the metal bump 12. Let it come. Further, another carrier copper foil 68 is allowed to face the anti-metal plate 2 side of the bonded body. FIG. 2C shows a state in which an adhesive body of the electrolytic copper foil 62 and the B-stage epoxy resin 4 and the carrier copper foil 68 are faced above the metal plate 2.
(D) Next, as shown in FIG. 2 (C), the adhesive and carrier copper foil 68 are bonded to the metal plate 1.
Pressurize 2 and heat to laminate. Thereby, the epoxy resin 4 becomes an interlayer insulating film in the C stage state. The pressurization and heating conditions for this lamination may be the same as those for the first embodiment shown in FIG.

(E) Next, the carrier copper foil 68, the electrolytic copper foil 62, the interlayer insulating film 4, and the metal bump 4 are connected between the metal bumps 4 and 4 of the electrolytic copper foil 62 without peeling off the carrier copper foil 68, for example. Polish until the surface of the portion (surface opposite to the roughened surface) is exposed. FIG.
) Shows the state after the polishing. By this polishing, the top surface of each metal bump 4 is exposed on the surface of the interlayer insulating film 4 and the surface of the electrolytic copper foil 62 (the surface opposite to the roughened surface) is between each metal bump 4. It will be exposed.
Note that the carrier copper foil 68 may be peeled off before the polishing.
(F) Next, as shown in FIG. 2F, a copper foil 70 for forming a wiring film is formed on the surface of the interlayer insulating film 68 by plating.
The copper foil 70 forms a wiring film forming metal layer, which is finally selectively etched to form a wiring film.

The plating for forming the copper foil 70 is performed in two stages, electroless plating and electrolytic plating. This is because, at the start of plating, the surface to be plated becomes the surface of the interlayer insulating film 4 except for the portion where the metal bumps 4 and the electrolytic copper foil 62 exist, and electroplating is impossible. This is because it is reasonable to perform electrolytic plating after the film has been formed on the entire surface with good film quality and high plating speed.
Such a copper foil (wiring film forming metal layer) 70 has a portion with the electrolytic copper foil 62 as a base,
Since the electrolytic copper foil 62 is bonded to the interlayer insulating film 4 made of resin through the roughened surface, the adhesiveness to the interlayer insulating film 4 is strong. That is, the peel strength (peeling strength) of the copper foil (wiring film forming metal layer) 70 with respect to the interlayer insulating film 4 can be increased.

In this embodiment, an epoxy resin is used as a resin for forming an interlayer insulating film, but a polyimide resin is used instead of an epoxy resin as long as it is a resin that can constitute a resist-coated kappa (RCC) type member. be able to.
Further, a resin containing cloth may be used as the resin for forming the interlayer insulating film. And it is not essential to use a peelable copper foil.
According to such an embodiment, similarly to the first embodiment, the conventional problem, that is, the polishing groove generated on the top surface of the metal bump, which has been caused by polishing the epoxy resin 4 in the B stage state, is obtained. (Polishing scratches) The B-stage resin is clogged as a resin residue, and the problem of the possibility that the connectivity between the metal bump and the metal layer or wiring layer connected at the top surface may be impaired is surely avoided. can do.

Polishing scraps can also be formed by the epoxy resin (interlayer insulating film) 4 in the C stage state by polishing. However, since it is polishing scraps from completely cured resin, the resin in the B stage state is polished into the polishing grooves (polishing scratches as in the prior art). ) And remains as a resin residue, and there is no fear that the good connectivity between the top surface of the metal bump and the metal layer is impaired. This point is also common to the first embodiment.
Further, since the prepreg has already changed from the B stage state to the C stage state during polishing, the interlayer insulating film 4 made of epoxy resin is not likely to be deteriorated by supplying a cooling liquid such as water.

Therefore, wet polishing becomes possible, and as a result, it is possible to continue polishing while cooling by wet polishing, and thus it is possible to perform smooth and quick polishing in common with the first embodiment.
As described above, the peel strength (peeling strength) of the copper foil (metal layer for wiring film formation) 70 with respect to the interlayer insulating film 4 can be increased.

3A to 3E show a third embodiment of the method for manufacturing a wiring board of the present invention in the order of steps (A) to (E).
FIG.
(A) A metal plate 2 obtained by polishing the interlayer insulating film 4 made of an epoxy resin in a C-stage state through the steps shown in FIGS. 1A to 1C until the top surface 12a of each metal bump 12 is exposed. obtain. Thereafter, it is preferable to roughen the surface of the interlayer insulating film 4, but there is a case where the surface is not roughened.
Thereafter, a nucleating agent 20 made of palladium is formed on the surface of the interlayer insulating film 4 and the top surface 12a of the metal bump 12 as a base for electroless plating. FIG. 3A shows the state after the nucleating agent 20 is formed. Even if the nucleating agent 20 is left as it is, the insulating property is not deteriorated so much. Therefore, it may be left, but it may be removed in a later step to ensure a higher insulating property.

(B) Next, as shown in FIG. 3B, the surface of the interlayer insulating film 4 and the top surface 1 of the metal bump 12
A plating mask film 22 made of, for example, a resist is formed on 2a. The plating mask film 2
2 is formed in a negative pattern with respect to the pattern of the wiring film to be formed.
(C) Next, on the surface of the interlayer insulating film 4 and the top surface 12a of the metal bump 12, a film serving as a base for electrolytic plating made of, for example, copper, nickel or tin is formed by electroless plating, and then the base film is formed. A film made of, for example, copper is formed by electrolytic plating as a base, and thus a wiring film 14 d having a negative pattern with respect to the pattern of the plating mask film 22 is formed. FIG.
(C) shows the state after the formation of the wiring film 14d.

(D) Next, as shown in FIG. 3D, the resist film 22 is removed.
(E) Next, as shown in FIG. 3E, the wiring film forming metal film 8 is patterned by selective etching, thereby forming a wiring film 8a.
As a modification of the present embodiment (second embodiment), although not shown in the drawings, the substrate 2a is formed at the previous stage shown in FIG. 3A, that is, before the nucleating agent (palladium particles) is formed. The metal layer on the back surface of the film is etched and removed to form a nucleating agent (palladium particles) for electroless plating on both sides.
A wiring board for forming a wiring film on both surfaces by forming a plating mask film on both surfaces and electrolessly plating the metal on both surfaces using the plating mask film as a mask, or by further electroplating after electroless plating. A manufacturing method is mentioned.

According to this embodiment, the resist film 22 serving as a mask is formed before plating for forming the metal layer 14.
Therefore, a negative pattern wiring film 14d can be obtained by plating at least with respect to the pattern of the resist film 22 serving as the mask.
Therefore, the wiring film 14 having a predetermined pattern is formed by plating without using selective etching.
Since d can be formed, side etching does not occur, and a fine and highly integrated wiring film 14d can be formed.

FIGS. 4A to 4D and FIGS. 5E and 5F are sectional views showing a fourth embodiment of the method for manufacturing a wiring board of the present invention in order of steps (A) to (F).
(A) For example, a wiring board having wiring films already connected to each other by metal bumps on both sides, for example, the manufacturing technique of the wiring board shown in FIG. 1 or the manufacturing technique of the wiring board shown in FIG. Prepared wiring board 2a is prepared. FIG. 4A shows the prepared wiring board 2a.
In FIG. 4, 4 is an interlayer insulating film formed by, for example, converting a B-stage epoxy resin into a C-stage state, 8a is a wiring film made of copper, for example, 10 is a metal layer for etching barrier made of nickel, for example, 12 Is a metal bump made of, for example, copper, and 14d is a wiring film made of, for example, copper.

(B) Next, an etching barrier metal layer 26 made of, for example, nickel is formed on both surfaces of the wiring board 2a by, for example, electroless plating, and thereafter a metal bump forming metal film 28 made of copper is formed on both surfaces thereof. . FIG. 4B shows a state after the metal bump forming metal film 28 is formed.
(C) Next, the metal bump forming metal films 28 on both surfaces of the wiring board 2a are selectively etched to form metal bumps 30 as shown in FIG.
(D) Next, each metal bump 30 is electrically isolated from the other metal bumps 30 by etching the etching barrier metal layer 26 made of nickel, for example, using the metal bumps 30 as a mask. FIG. 4D shows a state after the etching barrier metal layer 26 is etched.

(E) Next, a laminate composed of the epoxy resin 34 and the release sheet 36 is laminated on both surfaces of the wiring board 2a by pressing and heating, and the B stage epoxy resin 34 is brought into the C stage state. That is, the process (A) of the first embodiment shown in FIGS. 1 (A) and 1 (B).
The epoxy resin 34 covering the metal bump 30 is formed by the same process as (B), and then
The release sheet 36 is removed. FIG. 5E shows a state after the release sheet 36 is removed.
(F) Next, as shown in FIG. 5 (F), the double-sided epoxy resin 34 is attached to the metal bump 3.
Polish until zero top surface 30a is exposed. This polishing is performed by wet polishing.
Thereafter, although not shown, a wiring film is appropriately formed on the epoxy resin 34 on both sides. In this embodiment, the number of stages of the metal bumps 30 is three. However, the number of repetitions of a series of steps including the formation of the wiring film, the formation of the metal bumps, the formation of the interlayer insulating film, the C-stage, and the polishing is set. By increasing the number of metal bumps, the number of metal bumps can be further increased, thereby increasing the number of layers of the wiring board, and further increasing the integration density of the wiring board.

In this way, the wiring films 8a and 14d interconnected by the metal bumps 14 are formed on both surfaces of the interlayer insulating film 4 using epoxy resin, and the wiring films 8a,
A technique in which metal bumps 30 and 30 connected to 14d are formed, and then an interlayer insulating film 34 made of prepreg is formed on both surfaces by using substantially the same technique as the interlayer insulating film forming technique described above, followed by wet polishing. By making full use of, it is possible to increase the number of metal bumps and to increase the number of wiring boards.

FIGS. 6A to 6F are cross-sectional views showing a fifth embodiment of the method for manufacturing a wiring board of the present invention in the order of steps.
(A) For example, the wiring board 2b manufactured using the manufacturing technique of the wiring board shown in FIG. 1 or the manufacturing technique of the wiring board shown in FIG. 3 is prepared. FIG. 6A shows the prepared wiring board 2.
b [same structure as the wiring board 2a shown in FIG. 4A]. 4 is, for example, an interlayer insulating film formed by converting B-stage epoxy resin into C-stage, 8a is a wiring film made of, for example, copper, 10 is an etching barrier metal layer made of, for example, nickel, and 12 is made of, for example, copper A metal bump (first metal bump) 14d is a wiring film 14d made of, for example, copper.
It is.

(B) Next, as shown in FIG. 6B, a plating mask film 40 made of, for example, a resist is selectively formed on both surfaces of the wiring board 2b. The plating mask film 40 is formed so as to have a negative pattern with respect to the pattern of the second metal bump (42) to be formed later.
(C) Next, as shown in FIG. 6C, a metal such as copper is formed by electroless plating or electroless plating and subsequent electrolytic plating using the plating mask film 40 as a mask, Thus, the second metal bump 42 is obtained.
(D) Next, as shown in FIG. 6D, the plating mask film 40 made of resist, for example.
Remove.

(E) Next, as shown in FIG. 6 (E), a laminate of an epoxy resin 44 in a B-stage state and a release sheet 46 is laminated on both surfaces of the wiring board 2b by pressing and heating, and the epoxy resin 4
4 is an interlayer insulating film in a C-stage state. In this case, the pressure is, for example, 3.0 to 4.0 MPa.
The heating temperature is, for example, 160 to 250 ° C., whereby the epoxy resin 44 can be changed from the B stage to the C stage state, which is the same as the embodiment shown in FIG.
(F) Next, the release sheets 46 on both sides of the wiring board 2b are peeled off and removed, and then the top surface of the second metal bump 42 is exposed in the interlayer insulating film 44 made of epoxy resin in a C-stage state. Then, polishing is performed until the top surface is flat and expands to some extent (expansion to a size approximate to the cross-sectional area at the base portion of the metal bump 42).
As described above, since the interlayer insulating film 44 to be polished is made of an epoxy resin in a C-stage state, this polishing is possible.
Thereafter, although not shown, a wiring film having at least one connected to the second metal bump 42 on both sides is formed.

According to the present embodiment, both surfaces of the substrate 2b on which the wiring films 8a and 14d are formed on both surfaces of the interlayer insulating film 4 made of epoxy resin in a C-stage state penetrated by the first metal bumps 12 which are interlayer means. The plating mask film 40 is selectively formed, and the second metal bump 42 is formed by forming a metal using the plating mask film 40 as a mask, and then the above-described claim 1.
The interlayer insulating film 44 and the wiring film are formed by making full use of the interlayer insulating film formation and polishing technique described above, etc., so that a wiring board having a large number of layers having the metal bumps 12 and 42 in multiple stages can be obtained. it can.
Further, the metal bumps 42 are formed on both surfaces of the wiring board on which the metal bumps 12 and 42 are formed.
By repeating the series of steps of forming and polishing the interlayer insulating film 44 and forming the wiring film, it is possible to further increase the number of metal bumps 42, increase the number of wiring films, and increase the integration density of the wiring board. Can be planned.

The present invention may be used for manufacturing a wiring board using metal bumps made of, for example, copper as interlayer connection means and using, for example, a resin such as epoxy resin as an interlayer insulating film.

(A)-(G) is sectional drawing which shows the 1st Example of the manufacturing method of this invention wiring board to process order (A)-(G). (A)-(F) is sectional drawing which shows 2nd Example of the manufacturing method of this invention wiring board in order of a process ((A)-((F)). (A)-(E) is sectional drawing which shows the 3rd Example of the manufacturing method of this invention wiring board to process order (A)-(E). (A)-(D) is sectional drawing which shows process (A)-(D) in order of process (A)-(F) of the 4th Example of the manufacturing method of this invention wiring board. (E), (F) is sectional drawing which shows process (E), (F) in order of process (A)-(F) of the 4th Example of the manufacturing method of this invention wiring board. (A)-(G) is sectional drawing which shows the 5th Example of the manufacturing method of this invention wiring board to process order (A)-(G). (A)-(E) is sectional drawing which shows one prior art example of the manufacturing method of a wiring board in process order (A)-(E). (A), (B) shows the problems of the conventional example (problem to be solved by the present invention), (A) is a plan view showing the top surface of the metal bump, (B) shows the metal bump. It is sectional drawing.

Explanation of symbols

2, 2a ... wiring board, 4 ... interlayer insulating film made of resin, 6 ... release sheet,
8 ... Metal layer for forming a wiring film, 8a ... Wiring layer,
10 ... Metal layer for etching barrier (nickel film), 12 ... Metal bump,
12a: top surface of metal bump, 14a: electroless plating layer,
14b ... Electrolytic plating layer, 14d ... Wiring layer, 20 ... Nucleating agent, 22 ... Mask film,
26 ... Metal layer for etching barrier (nickel film),
28 ... Metal bump forming metal film (copper film), 30 ... Metal bump,
34 ... Interlayer insulating film made of resin, 36 ... Release sheet,
40 ... plating mask film, 42 ... metal bump (second metal bump),
44 ... Interlayer insulating film made of resin,
60 ... Laminate sheet (electrolytic copper foil with carrier copper foil),
62 ... metal layer (electrolytic copper foil), 66 ... first carrier foil (carrier copper foil),
68 ... second carrier foil (carrier copper foil),
70: Metal layer for forming a wiring film (copper foil by plating).

Claims (8)

On one side of the metal plate for wiring film formation in which metal bumps for interlayer connection are formed on one side,
Forming a B-stage resin having a thickness that completely covers the metal bump, which becomes an interlayer insulating film, and pressurizing and heating the resin to become a C-stage;
Wet polishing the surface of the resin that has become the C stage until the top surface of each metal bump is exposed;
A method of manufacturing a wiring board having 2. The method of manufacturing a wiring board according to claim 1, wherein a metal layer is formed by plating on the surface of the resin of the C stage and the top surface of the metal bump after the wet polishing step. Forming the metal layer for forming the wiring film by plating first forms a metal plating layer by electroless plating, and then forms a metal plating layer thicker than the metal plating layer by electroless plating by electrolytic plating. The method for manufacturing a wiring board according to claim 2, wherein: Forming a mask film having a negative pattern with respect to the pattern of the wiring film to be formed before plating the metal layer on the surface of the C-stage resin and the top surface of the metal bump. The method of manufacturing a wiring board according to claim 2 or 3, wherein One surface becomes an interlayer insulating film on the roughened surface of the metal layer roughened by electrolytic treatment, and a B-stage resin layer having a thickness smaller than the height of the metal bump described later is laminated,
The laminated body of the metal layer and the resin layer is arranged in such a direction that the resin layer faces the one surface of the metal plate for wiring film formation in which metal bumps for interlayer connection are formed on one surface. , By laminating by pressing and heating, the resin layer is made into a C stage,
Thereafter, the metal layer and the resin layer are wet-polished until the top surface of the metal bump is exposed and the other surface of the metal layer is exposed. After completion of the wet polishing, a metal layer for forming a wiring film is formed on the one surface of the wiring film forming metal plate by electroless plating and electrolytic plating to be in contact with the metal bumps at the top surface. The method for manufacturing a wiring board according to claim 5, wherein: On one side of the metal plate for wiring film formation in which metal bumps for interlayer connection are formed on one side,
Forming a B-stage resin with a thickness that completely covers the metal bumps, which will be an interlayer insulating film, and pressurizing and heating the resin so as to become a C-stage; and After the surface is wet-polished until the top surface of each metal bump is exposed, and after the wet-polishing step, patterning comprising a metal layer on the surface of the resin of the C stage and the top surface of the metal bump A series of steps consisting of forming the formed wiring film,
Thereafter, at least metal bumps connected to the wiring film are formed on the surface on which the wiring film is formed,
Thereafter, a process similar to the above series of processes is repeated at least once to obtain a circuit board having a plurality of metal bumps. A step of selectively forming a mask film on both surfaces of a substrate having a first metal bump formed on both surfaces of the interlayer insulating film and having a first metal bump passing through the interlayer insulating film and connecting between the wiring films on both surfaces When,
Forming a metal bump on both surfaces of the substrate by using the mask film as a mask to form a second metal bump made of the metal and connected to the wiring film;
Removing the mask film;
A B-stage resin for forming an interlayer insulating film having a thickness covering the second metal bumps is formed on both surfaces of the substrate, and the B-stage resin is brought into a C-stage state by pressurization and heating. A film forming step;
Polishing the interlayer insulating film made of resin made into the C stage until a flat top surface is formed on the metal bump;
A method of manufacturing a wiring board, comprising:

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