WO2017038713A1

WO2017038713A1 - Method for manufacturing printed wiring board, and method for manufacturing semiconductor device

Info

Publication number: WO2017038713A1
Application number: PCT/JP2016/075059
Authority: WO
Inventors: 宙早井; 猛八月朔日; 元山戸
Original assignee: 住友ベークライト株式会社
Priority date: 2015-08-31
Filing date: 2016-08-26
Publication date: 2017-03-09
Also published as: TW201735751A; KR102582537B1; KR20180048576A; JPWO2017038713A1

Abstract

This method for manufacturing a printed wiring board includes: a step for readying a structure in which a circuit board equipped with a circuit surface to which a circuit is provided, a solder resist film, and a metal film are laminated in the stated order; a step for selectively removing the metal film to form a first opening in the metal film; a step for removing the solder resist film in the region in which the first opening is formed to form, in the solder resist film, a second opening in which a part of the circuit is exposed; and a step for removing the metal film to expose the surface of the solder resist film.

Description

Printed wiring board manufacturing method and semiconductor device manufacturing method

The present invention relates to a method for manufacturing a printed wiring board and a method for manufacturing a semiconductor device.

The printed wiring board is composed of a laminated body in which a copper-clad laminated board serving as a core, an interlayer insulating material, and a solder resist are laminated in this order. A wiring pattern is provided on the surface of the printed wiring board. After the solder resist is formed, the solder resist is removed from the portion requiring electrical connection with the outside corresponding to the wiring pattern. A pattern is formed.

As a method for forming such a predetermined pattern, for example, the following exposure and development method is known. In the exposure and development method, first, a photomask having a pattern formed on the opening of a solder resist is laminated and exposed by a photographic method. Then, it develops with developing solutions, such as sodium carbonate, sodium hydroxide, and tetramethylammonium hydride (TMAH), and forms an opening part in a soldering resist.

However, the photosensitive resin used in the photographic method does not have sufficient rigidity, heat resistance, and insulation reliability required as the multilayer printed wiring board becomes thinner and denser than the thermosetting resin.
Therefore, in order to improve rigidity, heat resistance, and insulation reliability, a method is used in which a thermosetting resin is used as a material constituting the solder resist and an opening is formed in the solder resist by a laser (for example, Patent Document 1). reference.).

JP 2003-101244 A

However, in recent years, semiconductor elements and multilayer printed wiring boards have been increased in density for the purpose of lightening, thinning, and shortening semiconductor devices, and further miniaturization of wiring is required. When an opening is formed in a solder resist with a laser, it has become difficult to form a sufficiently fine and precise opening depending on the composition of the resin used for the solder resist.

As a result of the study by the present inventor, it is possible to form a fine and precise opening in the solder resist by using a metal film as a mask instead of a normal resist film formed of a thermosetting resin. As a result, the present invention has been completed.

According to the present invention, a step of preparing a structure in which a circuit board, a solder resist film, and a metal film are laminated in this order, and the first opening is formed by selectively removing the metal film. Forming a second opening in the solder resist film that exposes a part of the circuit by removing the solder resist film in a region where the first opening is formed; And removing the metal film to expose the surface of the solder resist film.

According to the present invention, a step of preparing a printed wiring board obtained by the method for manufacturing a printed wiring board,
Mounting a semiconductor element on the printed wiring board. A method for manufacturing a semiconductor device is provided.

ADVANTAGE OF THE INVENTION According to this invention, while being able to form a fine and precise opening part in a soldering resist, the productivity of a semiconductor device can be improved, and the manufacturing method of this printed wiring board The manufacturing method of the semiconductor device using the printed wiring board manufactured by is provided.

FIG. 1 is a schematic cross-sectional view showing an example of a method for manufacturing a printed wiring board according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing an example of a method for manufacturing a printed wiring board according to the present embodiment. FIG. 3 is a schematic diagram showing an example of the structure of the semiconductor package in the present embodiment. FIG. 4 is a schematic cross-sectional view showing an example of a modification of the method for manufacturing a printed wiring board according to the present embodiment.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

First, an outline of a method for manufacturing a printed wiring board according to the present embodiment will be described.

The method for manufacturing a printed wiring board of the present embodiment includes a step of preparing a structure including a metal film and a solder resist film, a step of forming an opening (first opening) in the metal film, and the metal film. And a step of forming an opening (second opening) in the solder resist film using the mask as a mask, and a step of removing the metal film to expose the surface of the solder resist film.

In the method of manufacturing a wiring board according to the present embodiment, by using a metal film such as a copper foil as a mask, laser burning around the laser irradiation portion of the solder resist film, which may occur when a pattern is directly formed by a laser, etc. Can be prevented. Thereby, a fine and precise opening (pattern) can be formed on the solder resist film rather than directly forming a pattern with a laser.

[Method of manufacturing printed wiring board]
Hereinafter, the method for manufacturing the printed wiring board of the present embodiment will be described in detail with reference to FIGS.
1 and 2 are schematic cross-sectional views illustrating an example of a method for manufacturing a printed wiring board according to the present embodiment.

The method for manufacturing the printed wiring board 20 according to the present embodiment includes a structure in which a circuit board (core board 22), a solder resist film (insulating resin film 10), and a metal film (metal film 12) are laminated in this order. The step of preparing (FIG. 1B), the step of forming the opening (first opening 21) by selectively removing the metal film 12, and the opening 21 (FIG. 1C). A step of exposing a part of the circuit (conductor pattern 24) to the bottom of the opening 28 by removing the solder resist film in the region where the film is formed and forming an opening (second opening 28). (FIG. 1 (d)), the step of removing the metal film to expose the surface (surface 11, surface 13) of the solder resist film (FIG. 2 (a)), and exposing to the bottom of the opening 28. Forming a metal layer (plating film 246) on the circuit (FIG. 2 ( )), Including.

Further, as the structure, one surface (surface 11, surface 13) of the solder resist film (insulating resin film 10) may be disposed opposite to one surface (surface 15) of the metal film 12. On the other hand, the other surface of the solder resist film (opposite surfaces of the surface 11 and the surface 13) is arranged to be opposed to the circuit surface on which the circuit (conductor pattern 24) of the circuit substrate (core substrate 22) is formed. be able to.

Hereinafter, each step will be described.
First, the structure is prepared. In the present embodiment, the step of preparing the structure includes the metal film so that one surface (surface 15) of the metal film 12 faces the one surface (surface 11, surface 13) of the solder resist film (insulating resin film 10). 12 is prepared, and the other surface of the solder resist film (opposite surfaces of the surface 11 and the surface 13) and the circuit surface of the circuit board (core substrate 22) are opposed to each other. And a step of preparing the structure by bonding.

Specifically, first, as shown in FIG. 1A, a core substrate 22 having a conductor pattern 24 provided on at least one outermost surface on the front and back sides is prepared. The core substrate 22 can constitute, for example, a core layer of a printed wiring board. As the core layer, for example, a resin substrate obtained by curing a prepreg impregnated with a fiber base material can be used. In the present embodiment, as the core substrate 22, a plurality of buildup layers (not shown) may be formed on the core layer, but the core layer may be formed alone.

Next, as shown in FIG. 1B, the metal film 12 is disposed so that one surface (surface 15) of the insulating resin film 10 faces one surface (surface 11, surface 13). An insulating resin film 10 is prepared. This insulating resin film 10 becomes a solder resist film of the structure. In the present embodiment, a resin film with a metal film in which the metal film 12 is provided on the insulating resin film 10 can be used. As the resin film with a metal film, for example, a resin film protected with a cover film can be used. That is, a laminate in which a cover film, a resin film (insulating resin film 10), and a metal film 12 are laminated in this order can be used. Examples of the cover film include polymer films such as polyethylene and polypropylene. In this embodiment, the said resin film with a metal film is obtained by peeling a cover film from a laminated body, for example. Thereby, the insulating resin film 10 with the metal film 12 can be prepared.

In addition, it is preferable that one surface (surface 15) opposed to one surface (surface 11, surface 13) of the solder resist film (insulating resin film 10) is a smooth surface.
Generally, a relatively rough surface is formed on the bonding surface of the copper foil for the purpose of improving the peel strength after lamination. In the present embodiment, the smooth surface of a metal film (for example, a metal foil such as a copper foil) means that there are few surface irregularities. In this case, for example, the surface roughness Rz of the smooth surface is preferably 3.0 μm or less, more preferably 2.0 μm or less, and further preferably 0.1 μm or more and 1.8 μm or less. The surface roughness (Rz) can be calculated by the 10-point average roughness shown in JIS B0601. In the case of the metal film 12 having a rough surface (surface 15) (surface roughness Rz is greater than 3.0 μm), the surface roughness Rz of the surface (surface 15) is within the above range. A smoothing process may be performed on the one surface 15 of the metal film 12 to make it smooth.

In the method for manufacturing a printed wiring board of this embodiment, the surface of the solder resist film can be made smooth by using a metal film mask having a smooth surface. Thereby, stability of a manufacturing process of a printed wiring board or a semiconductor device can be improved. Specifically, when the manufactured printed wiring board is ultrasonically inspected, bubbles are hardly formed on the surface of the outermost solder resist film, so that the accuracy of the ultrasonic inspection can be improved. Moreover, it can suppress that a damage | wound is made during a manufacturing line. Moreover, it can suppress that a printed wiring board after manufacture produces a damage | wound. Thereby, the yield can be improved. Furthermore, the solder flux can be easily cleaned. When the solder flux remains, the heat resistance may be lowered, but it is possible to reliably prevent the heat resistance of the printed wiring board after manufacture from being lowered. Further, the contrast becomes clear and the alignment mark can be easily recognized. A printed wiring board and a semiconductor package obtained by such a printed wiring board manufacturing method can have a structure with excellent product reliability.

As the metal film 12, a metal foil having a smooth surface on at least one surface can be used. Specifically, for example, a peelable metal foil having an extremely thin metal foil having a smooth surface, a release layer, and a carrier foil may be used. That is, the peelable metal foil is thermocompression bonded to the insulating resin film 10, and then the carrier foil is peeled off together with the peeling layer, whereby the insulating resin film 10 with an ultrathin metal foil (metal film 12) is obtained. The ultrathin metal foil (metal film 12) has a smooth surface formed on the adhesive surface with the insulating resin film 10. On the other hand, the insulating resin film 10 can be in a B-stage state. That is, the smooth surface of the metal film 12 is in contact with the surface (surface 11, surface 13) of the insulating resin film 10. As a result, the surface shape of the smooth surface of the metal film 12 is also transferred to the surface (surface 11, surface 13) of the insulating resin film 10 to form a smooth surface.

In this embodiment, as the metal foil having a smooth surface, for example, non-roughened copper foil or the like can be used. As the non-roughened copper foil, for example, a non-roughened copper foil with a primer resin layer (MT18DMT, manufactured by Mitsui Mining & Smelting Co., Ltd.) can be used.

Although it does not specifically limit as a metal which comprises the said metal film 12 (for example, ultra-thin metal foil), For example, copper and \ or a copper-type alloy, aluminum and \ or an aluminum-type alloy, iron and \ or an iron-type alloy, Examples thereof include silver and / or silver-based alloys, gold and gold-based alloys, zinc and zinc-based alloys, nickel and nickel-based alloys, tin and tin-based alloys, and the like. For example, by using a copper foil as the metal film 12, the cost can be reduced compared to other materials. Moreover, since it can be applied to the current infrastructure equipment, a highly versatile process can be performed.

The lower limit value of the thickness of the metal film 12 is not particularly limited, but may be, for example, 1 μm or more, and may be 10 μm or more. The upper limit value of the film thickness of the metal film 12 is not particularly limited, but may be, for example, 30 μm or less, or 25 μm or less. By setting it to the above lower limit value or more, it is possible to maintain the mask function when the opening 28 is formed in the solder resist film 10 after the cover film is peeled off. Moreover, by setting it as below an upper limit, workability can be improved and process efficiency can be improved. For example, in the case of a peelable copper foil (metal film 12) with a carrier copper foil, the thickness may be 1 μm or more and 5 μm or less.

The thickness of the insulating resin film 10 is not particularly limited, but may be, for example, 10 μm or more and 50 μm or less. Thereby, the balance of mechanical strength and opening characteristic can be aimed at.

Subsequently, the insulating resin film 10 with the metal film 12 is laminated on the conductor pattern 24 of the core substrate 22 as shown in FIG. For example, the insulating resin film 10 with the metal film 12 can be attached to the surface of the core substrate 22 on which the conductor pattern 24 is provided so that the insulating resin film 10 faces the core substrate 22. In the present embodiment, the attaching step can be performed, for example, by laminating the insulating resin film 10 with the metal film 12 on the conductor pattern 24 and then vacuum-pressing these laminated bodies. As described above, the structure can be prepared.

Next, as shown in FIG. 1C, the metal film 12 is selectively removed. Thereby, the opening 21 can be formed in a predetermined region of the metal film 12 on the conductor pattern 24. A method for forming the opening 21 is not particularly limited, and for example, a method such as exposure and development can be used.

Next, as shown in FIG. 1D, an opening 28 is formed in a predetermined region of the insulating resin film 10 using the metal film 12 with the opening formed as a mask. The opening 28 is formed so as to mainly expose the land 244 of the conductor pattern 24. A method for forming the opening 28 is not particularly limited, and for example, a laser processing method, a chemical etching processing method, a blast processing method, or the like can be used.

In particular, in this embodiment, the process can be simplified by using a laser processing method. Since the insulating resin film 10 in the B-stage state can be used, the workability of the insulating resin film 10 can be improved as compared with the case of the cured product.
In addition, as a method of obtaining the insulating resin film 10 in the B stage state, for example, a method of heating at a temperature of 100 ° C. or more and 170 ° C. or less can be cited. The lower limit of the heating temperature is preferably 120 ° C. or higher, and the upper limit is preferably 150 ° C. or lower.

After the opening 28 is formed, the insulating resin film 10 can be thermally cured as shown in FIG. Thereby, the solder resist film 14 is formed. In the present embodiment, the lower limit of the curing temperature is not particularly limited, but is preferably 200 ° C. or higher, more preferably 210 ° C. or higher, and further preferably 220 ° C. or higher. Although it does not specifically limit as an upper limit of hardening temperature, For example, it can be 250 degrees C or less.
In addition, after forming the opening part 28, a desmear process can be performed as needed. In the desmear process, smear generated due to the formation of the opening 28 is removed.

Subsequently, the metal film 12 on the surface (surface 11, surface 13) of the solder resist film 14 is removed. The method for removing the metal film 12 is not particularly limited, but for example, flash etching can be used. Thereby, the surface of the solder resist film 14 can be exposed. Further, the surface of the solder resist film 14 after the removal of the metal film 12 can be made smooth. In the present embodiment, it is preferable that at least the surface of the solder resist film 14 positioned at the outermost layer (for example, the surface 11 shown in FIG. 3) is a smooth surface.

Subsequently, as shown in FIG. 2B, a plating process for forming a plating film 246 on the conductor pattern 24 exposed in the opening 28 is performed. However, the printed wiring board 20 may be used without forming the plating film 246. The plating film 246 can be, for example, a plating film having a two-layer structure in which a gold plating film is laminated on a solder plating film, a tin plating film, or a nickel plating film. The plating film 246 is formed so as to cover the conductive portion of the conductor pattern 24 exposed in the opening 28. Moreover, the film thickness of the plating film 246 is not particularly limited, but may be, for example, 2 μm or more and 10 μm or less. Thereby, the land 244 portion can be a connection portion suitable for wire bonding or soldering in a mounting process using the printed wiring board 20.

The method for the plating treatment is not particularly limited, and a known method can be used. For example, an electrolytic plating method or an electroless plating method can be used. For example, when the electroless plating method is used, the plating film 246 can be formed as follows. Here, an example of forming the plating film 246 having a two-layer structure of nickel and gold will be described, but the present invention is not limited to this. First, a nickel plating film is formed. When performing electroless nickel plating, the core substrate 22 in which the conductor pattern 24 and the insulating resin film 10 are laminated is immersed in a plating solution. Thereby, a nickel plating film can be formed on the conductive portion of the conductor pattern 24 exposed in the opening 28. As the plating solution, a mixed solution containing nickel lead and, for example, hypophosphite as a reducing agent can be used. Subsequently, electroless gold plating is performed on the nickel plating film. Although the method of electroless gold plating is not particularly limited, for example, it can be performed by substitution gold plating performed by substitution of gold ions and ions of a base metal.
In addition, you may perform the process of wash | cleaning the conductive part of the exposed conductor pattern 24, and the process of roughening before a plating process as needed.

As described above, the printed wiring board 20 according to the present embodiment shown in FIG. 2B is obtained.

In this embodiment, although the example using the insulating resin film 10 with the metal film 12 was demonstrated, it is not limited to this, You may use the insulating resin film 10 with a carrier base material.
Hereinafter, a modification of the insulating resin film 10 will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view showing an example of a modification of the method for manufacturing a printed wiring board according to the present embodiment.

In the method for manufacturing a printed wiring board shown in FIG. 4, the step of preparing the structure includes a solder resist film (insulating resin film 10) in which the main surface of the carrier base material (carrier base material 8) is disposed on one side. The step of preparing, the step of bonding the other surface of the solder resist film (insulating resin film 10) and the circuit surface of the circuit board, and bonding the carrier base material from the solder resist film (insulating resin film 10) Peeling and forming a metal film (metal film 12) on the peeled surface of the solder resist film (insulating resin film 10) to prepare a structure.

Each process of the manufacturing method of the printed wiring board concerning the modification of this embodiment is explained.
First, the insulating resin film 10 with the carrier base material 8 is prepared. For example, the insulating resin film 10 with the carrier substrate 8 may be protected by a cover film. The insulating resin film 10 with the carrier substrate 8 is obtained by peeling the cover film from the laminate composed of the cover film, the resin film (insulating resin film 10), and the carrier substrate 8. As the carrier substrate 8, for example, a polymer film such as polyethylene terephthalate can be used. The insulating resin film 10 can be a B-stage resin film.

Subsequently, as shown in FIG. 4A, the insulating resin film 10 of the insulating resin film 10 with the carrier base material 8 is bonded onto the conductor pattern 24 of the core substrate 22.

Subsequently, as shown in FIG. 4B, the carrier base material 8 is peeled from the insulating resin film 10. Thereby, the surface (surface 11, surface 13) of the insulating resin film 10 is exposed.

Subsequently, as shown in FIG. 4C, a metal film 12 is pasted on the surface of the insulating resin film 10. It is preferable that a smooth surface is formed on the attachment surface (surface 15) of the metal film 12. In the present embodiment, for example, the metal film 12 can be formed using a peelable metal foil. That is, the peelable metal foil is attached to the insulating resin film 10, and then the carrier metal foil and the release layer are peeled from the peelable metal foil, whereby the ultrathin metal foil (metal film 12) is attached to the surface of the insulating resin film 10 ( Surface 11 and surface 13). As described above, the structure of the present embodiment can be prepared.
In the steps after FIG. 4C, the steps shown in FIGS. 1C to 2B can be performed. Thereby, the printed wiring board 20 of this embodiment shown in FIG.2 (b) is obtained.

[Method for Manufacturing Electronic Device]
Next, a method for manufacturing the semiconductor package 102 will be described.
The manufacturing method of the electronic device (semiconductor package 102) according to the present embodiment includes a step of mounting the semiconductor element 60 (electronic element) on the printed wiring board 20 obtained by the above-described printed wiring board manufacturing method. More specifically, a step of preparing the printed wiring board 20, a step of disposing the semiconductor element 60 on the printed wiring board 20, and a step of sealing the semiconductor element 60 are included in this order.

That is, the manufacturing method of the semiconductor package 102 includes a step of preparing a substrate (core substrate 22) on which a conductive circuit (conductive pattern 24) is formed on one surface, and a step of disposing a resin film (the insulating resin film) on the substrate. A step of forming an opening (second opening 28) in the resin film to expose the conductive circuit, and a step of forming a solder resist film (solder resist film 14) by heat-treating the resin film. The step of electrically connecting the electronic element to the conductive circuit exposed in the opening and the step of sealing the electronic element (semiconductor element 60) can be included. The resin film is preferably formed using a solder resist resin composition described later. That is, this resin film may be constituted by a coating film of the solder resist resin composition or a resin sheet described later. In the present embodiment, the resin film is formed on both surfaces of the substrate (core substrate 22), and at least the resin film disposed on the surface opposite to the surface on which the electronic element is mounted is It is preferable to use a resin composition for a solder resist described later.

By the way, the manufactured printed wiring board 20 is inspected for cracks and peeling by ultrasonic inspection or the like after manufacturing the electronic device (semiconductor package 102). Here, when the surface of the solder resist film 14 is a smooth surface, since no bubbles are formed on the surface of the solder resist film 14 during the inspection, cracks and peeling can be found more reliably. That is, a more accurate inspection can be performed. At the stage of product inspection of the printed wiring board 20, it becomes easy to eliminate defective products. As a result, the productivity of the electronic device can be improved. In particular, when the opening 28 (pattern) formed in the solder resist film 14 is fine, it tends to be difficult to find defects such as cracks, but the surface of the solder resist film 14 is a smooth surface. A highly accurate inspection can be easily performed.

In this embodiment, in the step of preparing the printed wiring board 20, the printed wiring board 20 with the insulating resin film 10 (resin film made of a resin composition for solder resist) exposed on the surface is prepared. In the step of disposing the semiconductor element 60, the semiconductor element 60 is disposed on the insulating resin film 10. In the step of sealing the semiconductor element 60, the exposed insulating resin film 10 and the semiconductor element 60 are sealed so as to be covered with a sealing resin. The printed wiring board 20 includes a core substrate 22, a conductor pattern 24, and the insulating resin film 10. The conductor pattern 24 is provided on at least one outermost surface of the core substrate 22. The insulating resin film 10 is the outermost layer of the printed wiring board 20 and is provided on the conductor pattern 24. The insulating resin film 10 is provided with a plurality of openings 28. A part of the conductive portion of the conductor pattern 24 is located in the at least one opening 28.

First, the above-described printed wiring board 20 is prepared (step of preparing a printed wiring board), and a semiconductor element 60 is disposed on the printed wiring board 20 (step of disposing a semiconductor element). At this time, the semiconductor element 60 is mounted on the printed wiring board 20 via a die attach material 62, for example. The bonding wire 50 that connects the semiconductor element 60 and the printed wiring board 20 is bonded to, for example, the conductor pattern 24 exposed in the opening 28 on the upper surface of the printed wiring board 20. Next, the upper surface of the printed wiring board 20, the semiconductor element 60, and the bonding wire 50 are sealed with the sealing resin layer 40 (step of sealing). For example, an epoxy resin composition can be used as the sealing resin. As a method of molding with a sealing resin, a transfer molding method, an injection molding method, a transfer method, a coating method, or the like can be used. The sealing resin layer 40 is cured by heating at 150 ° C. or higher and 200 ° C. or lower, for example.

In the example in which the solder balls 30 as the external connection terminals are provided on the printed wiring board 20, the solder balls 30 are formed on the conductor pattern 24 exposed at the opening 28 on the lower surface side, for example. In addition, although the example of the package of the flip chip connection was demonstrated as the semiconductor package 102 which concerns on this embodiment, the semiconductor package 102 is not limited to this, The package connected by wire bonding or TAB may be sufficient.

[Printed wiring board]
The printed wiring board according to the present embodiment will be described.
FIG. 2B is a schematic diagram illustrating an example of the structure of the printed wiring board 20 in the embodiment.
The printed wiring board of the present embodiment includes a substrate (core substrate 22), a conductive circuit (conductor pattern 24) formed on the substrate, and a solder resist film 14 formed on the outermost layer of the substrate. Can do. The solder resist film 14 is obtained by curing a solder resist resin composition described later. For example, the solder resist film 14 can be composed of a cured product of a resin sheet formed of a resin composition for solder resist described later.

A printed wiring board 20 shown in FIG. 2B includes a core substrate 22, a conductor pattern 24, and a solder resist film 14. The conductor pattern 24 is provided on at least one outermost surface of the core substrate 22. The solder resist film 14 constitutes the outermost layer of the printed wiring board 20. The solder resist film 14 is provided around the conductor pattern 24. The solder resist film 14 is provided with a plurality of openings 28. A part of the conductive portion of the conductor pattern 24 is located in the at least one opening 28. Further, the surface (surface 11, surface 13) of the solder resist film 14 is formed with a smooth surface.

In the printed wiring board 20 according to the present embodiment, the core substrate 22 is a substrate including at least one insulating layer. The insulating layer provided in the core substrate 22 is, for example, a resin base material obtained by impregnating a fiber base material with a resin composition.
The core substrate 22 can be a substrate made of a thermosetting resin. The core substrate 22 may be a rigid substrate or a flexible substrate. The thickness of the core substrate 22 is not particularly limited, but can be, for example, 10 μm or more and 300 μm or less.

Further, the core substrate 22 may be a single-sided plate having only one insulating layer and having a conductor pattern 24 formed on only one side thereof, or having only one insulating layer on both the front and back surfaces. A double-sided board provided with the conductor pattern 24 or a multilayer board having two or more insulating layers may be used. When the core substrate 22 is a multilayer board, one or more wiring layers sandwiched between two insulating layers are formed in the core substrate 22.
When the core substrate 22 is a double-sided board or a multilayer board, the conductor pattern 24 provided on one surface (outermost surface) of the core substrate 22 is a conductor provided on the opposite surface (outermost surface). The wiring layer provided inside the pattern 24 and the core substrate 22 is electrically connected to each other through a through hole (not shown) penetrating at least a part of the insulating layer.

The conductor pattern 24 is provided on at least one surface (outermost surface) of the front surface and the back surface of the core substrate 22. The conductor pattern 24 is, for example, a pattern formed by selectively etching a copper film laminated on the core substrate 22. The conductor pattern 24 includes at least a land 244 and a line 242 as a conductive portion. The land 244 is mainly a connection part that electrically connects an element or component mounted on the printed wiring board 20 and the conductor pattern 24, for example, another part of the conductor pattern 24 or a wiring in the core substrate 22. A circular or square part connected to a layer. Note that a hole for inserting a terminal of an electronic component or the like may be provided at the center of the land 244. The line 242 is mainly a linear portion that electrically connects the lands 244 to each other.

The solder resist film 14 is laminated on the conductor pattern 24. Since the solder resist film 14 can maintain insulation, a highly reliable printed wiring board can be obtained. Moreover, since the said soldering resist film | membrane 14 is arrange | positioned at the upper and lower outermost layers, it can exhibit, for example in black, and can improve the aesthetics also on the lower surface of a printed wiring board. Further, a mark can be printed on the lower surface of the solder resist film 14 by a laser such as a YAG laser.

The solder resist film 14 is provided with an opening mainly corresponding to a region where the land 244 of the core substrate 22 is provided, and the land 244 is not covered with the solder resist film 14. That is, the solder resist film 14 is not provided on the land 244, and the land 244 is exposed. Note that a conductive film such as a nickel and gold plating film or a solder plating film may be laminated on the land 244. In the printed wiring board 20 according to the present embodiment, a plating film 246 is further provided on the land 244 located in the opening. The solder resist film 14 may be further provided with an opening in a portion other than the land 244, or may have an opening that exposes a part of the line 242. Further, it is not necessary for all of the lands 244 to be located in the openings, and there may be lands 244 covered with the solder resist film 14.

The printed wiring board 20 can be used as an interposer or a mother board, for example. The package refers to a package in which various parts are mounted on a printed wiring board and sealed together. The semiconductor package is an example of a package, and the package includes a batch sealed ECU (Electric Control Unit) and the like.

[Electronic device]
Next, the semiconductor package 102 according to the present embodiment will be described.
FIG. 3 is a schematic cross-sectional view showing an example of the structure of the semiconductor package 102 according to the present embodiment.
The electronic device (semiconductor package 102) of this embodiment can include the printed wiring board (printed wiring board 20) and an electronic element (semiconductor element 60) mounted on the printed wiring board. That is, the electronic device can be used as a semiconductor device. Of the solder resist film constituting the outermost layer of this printed wiring board, the solder resist film (the solder resist film 14 on the lower layer side) disposed on the surface opposite to the surface on which the electronic elements are mounted will be described later. It is obtained by curing a resin composition for solder resist.

The semiconductor package 102 shown in FIG. 3 includes a printed wiring board 20, a semiconductor element 60, and a sealing resin layer 40. The semiconductor element 60 is disposed on the printed wiring board 20. The sealing resin layer 40 covers at least one surface of the printed wiring board 20 and the semiconductor element 60. The printed wiring board 20 includes a core substrate 22, a conductor pattern 24, and a solder resist film 14. The conductor pattern 24 is provided on at least one outermost surface of the core substrate 22. The solder resist film 14 is the outermost layer of the printed wiring board 20 and is provided around the conductor pattern 24.

In the semiconductor package 102 according to the present embodiment, at least one semiconductor element 60 is disposed on the insulating resin film 10 on one surface (hereinafter referred to as “upper surface”) of the printed wiring board 20 described above. Yes. In the semiconductor package 102, the printed wiring board 20 is, for example, an interposer, and the semiconductor element 60 is, for example, an LSI chip cut out from a semiconductor wafer. In addition to the semiconductor element 60, for example, an electronic component that functions as a resistor or a capacitor may be further disposed on the upper surface of the printed wiring board 20. The semiconductor element 60 is fixed on the insulating resin film 10 via a die attach material 62.

The semiconductor element 60 is provided with an electrical connection pad (not shown) on its surface, and the connection pad is connected to a circuit built in the semiconductor element 60, for example. A land 244 which is a part of the conductor pattern 24 provided on the printed wiring board 20 is provided in the opening 28 of the solder resist film 14. The land 244 and the connection pad of the semiconductor element 60 are connected by a bonding wire 50. In the semiconductor package 102 according to the present embodiment, the plating film 246 is further provided on the land 244, and the land 244 is connected to the bonding wire 50 through the plating film 246. However, the present invention is not limited to this. . Further, instead of being connected by the bonding wire 50, it may be connected by a lead wire or solder.

The sealing resin layer 40 includes a solder resist film 14 exposed on the upper surface of the printed wiring board 20, the core substrate 22, a plating film 246 (a land 244 if no plating film 246 is provided), and a semiconductor element 60. Of these, the surface other than the surface bonded to the printed wiring board 20 by the die attach material 62 and the bonding wire 50 are covered. The sealing resin layer 40 may cover the entire surface of the printed wiring board 20 on which the semiconductor element 60 is provided, or may cover a part of the surface exposed.

The printed wiring board 20 of the semiconductor package 102 is further provided with a plurality of openings 28 and lands 244 inside the openings 28 on the surface opposite to the upper surface (hereinafter referred to as “lower surface”). Each land 244 is covered with a plating film 246, and further solder balls 30 are provided to cover the plating film 246.
Here, an example of a flip chip connection package has been described as the semiconductor package 102 according to the present embodiment, but the present invention is not limited to this, and a package that is connected by wire bonding or TAB (Tape Automated Bonding) may be used.

Further, a mark is printed on the upper surface of the solder ball 30 or the lower surface of the solder resist film 14 by a laser such as a YAG laser, for example. This mark is made up of, for example, at least one of letters, numbers, or symbols consisting of straight lines or curves. The mark indicates, for example, the product name, product number, lot number, or manufacturer name of the semiconductor package. The mark may be stamped by, for example, a YVO ₄ laser, a carbonic acid laser, or the like.

The semiconductor device according to the present embodiment is not particularly limited. For example, QFP (Quad Flat Package), SOP (Small Outline Package), BGA (Ball Grid Array), CSP (Chip Size Package), QFN (Quad Flat Flat). lead Package), SON (Small Outline Non-leaded Package), LF-BGA (Lead Frame BGA), and the like.

In addition, examples of the semiconductor element include, but are not limited to, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and a solid-state imaging element.

[Resin composition for solder resist]
The resin composition for solder resist used in the method for producing a printed wiring board of this embodiment will be described in detail below.
The solder resist resin composition is a varnish-like resin composition. A resin sheet can be obtained by forming the solder resist resin composition into a film. The solder resist film 14 is obtained by curing the resin sheet. Moreover, you may obtain the soldering resist film 14 by hardening the coating film of the resin composition for soldering resists.

As the resin composition for solder resist, a thermosetting resin composition containing a thermosetting resin can be used. The thermosetting resin is not particularly limited. For example, phenol resin, resin having a benzoxazine ring, epoxy resin, acrylic resin, melamine resin, unsaturated polyester resin, maleimide resin, polyurethane resin, diallyl phthalate resin, silicone Examples thereof include resins, cyanate resins, and resins having a methacryloyl group. For example, the thermosetting resin may be a liquid resin that is liquid at room temperature (25 ° C.). These can be used alone or in combination of two or more. In the present embodiment, the thermosetting resin preferably includes an epoxy resin.

(Epoxy resin (A))
The epoxy resin (A) includes, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4 ′-(1,3-phenylenedioxide). Isopropylene) bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4 ′-(1,4-phenylenediisopridiene) bisphenol type epoxy resin), bisphenol Z type epoxy resin (4,4′-cyclohexene) Bisphenol type epoxy resins such as sidiene bisphenol type epoxy resins; phenol novolak type epoxy resins, cresol novolak type epoxy resins, tetraphenol group ethane type novolak type epoxy resins, novola having a condensed ring aromatic hydrocarbon structure Novolak type epoxy resins such as epoxy resins; biphenyl type epoxy resins; aralkyl type epoxy resins such as xylylene type epoxy resins and biphenyl aralkyl type epoxy resins; naphthylene ether type epoxy resins, naphthol type epoxy resins, naphthalenediol type epoxy resins Epoxy resins having a naphthalene skeleton such as bifunctional to tetrafunctional epoxy type naphthalene resins, binaphthyl type epoxy resins, naphthalene aralkyl type epoxy resins, naphthalene modified cresol novolac epoxy resins; anthracene type epoxy resins; phenoxy type epoxy resins; dicyclopentadiene Type epoxy resin; norbornene type epoxy resin; adamantane type epoxy resin; containing one or more selected from fluorene type epoxy resin Can. Among these, it is more preferable to include an epoxy resin having a naphthalene skeleton from the viewpoint of improving the embedding property of the solder resist film and the surface smoothness. Thereby, the low linear expansion and high elastic modulus of the solder resist film can be achieved. It is also possible to improve the workability by improving the rigidity of the printed wiring board, and to improve the reflow resistance and suppress the warpage in the semiconductor package. From the viewpoint of improving the embedding property of the solder resist film, it is particularly preferable to include an epoxy resin having a tri- or higher functional naphthalene skeleton.

It is mentioned as an example of a preferable aspect that the epoxy resin shown to the following General formula (1) is included as an epoxy resin (A).

(In the formula (1), n is an integer of 0 to 10, and R ₁ and R ₂ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. )

The content of the epoxy resin (A) is, for example, preferably 3% by weight or more and more preferably 5% by weight or more with respect to the total solid content of the thermosetting resin composition. By making content of an epoxy resin (A) more than the said lower limit, it can contribute to the improvement of the embedding property and smoothness of the soldering resist film formed using a thermosetting resin composition. On the other hand, the content of the epoxy resin (A) is preferably 40% by weight or less, and more preferably 35% by weight or less, for example, based on the total solid content of the thermosetting resin composition. By making content of an epoxy resin (A) below the said upper limit, the heat resistance and moisture resistance of a soldering resist film formed using a thermosetting resin composition can be improved. In addition, the total solid content of a thermosetting resin composition refers to the whole component except the solvent contained in a thermosetting resin composition. The same applies hereinafter.

(Filler (B))
The thermosetting resin may further include a filler (B).
An inorganic filler can be used as the filler (B). Examples of the inorganic filler include, but are not limited to, silicates such as talc, calcined clay, unfired clay, mica, and glass; oxides such as titanium oxide, alumina, boehmite, silica, and fused silica; calcium carbonate Carbonates such as magnesium carbonate and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate and calcium sulfite; zinc borate and metaborates Borates such as barium oxide, aluminum borate, calcium borate and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride and carbon nitride; titanates such as strontium titanate and barium titanate Can be mentioned. Among these, talc, alumina, glass, silica, mica, aluminum hydroxide, and magnesium hydroxide are preferable.

The silica is not particularly limited, but may include, for example, at least one of spherical silica and crushed silica. From the viewpoint of improving the embedding property and surface smoothness of the solder resist film, it is more preferable to include spherical silica. The silica may be, for example, fused spherical silica.

The lower limit of the average particle diameter _{D 50} of the filler (B) is not particularly limited, is preferably at least 0.01 [mu] m, more preferably not less than 0.05 .mu.m. The upper limit of the average particle diameter _{D 50} of the filler (B) is not particularly limited, is preferably from 5.0 .mu.m, more preferably 2.0μm or less, more preferably 1.0μm or less.

As the silica include, but are not limited to an average particle size _{D 50} in particular, for example, an average particle diameter _{D 50} may be used fine particles of silica is 2nm or 100nm or less. Thereby, the embedding property and surface smoothness of a solder resist film can be improved more effectively. In the present embodiment, the particulate silica having an average particle diameter _{D 50} is 2nm or 100nm or less, that the average particle diameter _{D 50} comprises a 100nm excess of silica, in both the thermosetting resin composition, filling properties And an example of a preferred embodiment for improving surface smoothness.

The average particle diameter _{D 50} of the filler (B), for example a laser diffraction particle size distribution analyzer (HORIBA Ltd., LA-500) can be measured using a. In the present embodiment, the filler may include one kind or two or more kinds.

In preparing the thermosetting resin composition, it is more preferable to use, for example, a silica raw material having a silica concentration of 10 wt% or more and 90 wt% or less as silica. From the viewpoint of improving the mechanical strength of the printed wiring board, it is particularly preferable to use a silica raw material having a silica concentration of 50% by weight to 90% by weight. Further, from the viewpoint of suppressing the deflection of the printed wiring board and improving the moisture absorption reliability of the semiconductor device, for example, a silica raw material having a silica concentration of 50% by weight to 90% by weight and a silica concentration of 10% by weight to 50%. It is particularly preferable to use a silica raw material of not more than% by weight in combination.

The content of the filler (B) is, for example, preferably 30% by weight or more and more preferably 50% by weight or more with respect to the total solid content of the thermosetting resin composition. By making content of a filler (B) more than the said lower limit, the heat resistance and moisture resistance of the soldering resist film obtained using a thermosetting resin composition can be improved effectively. It is also possible to contribute to the reduction of warpage of the resulting semiconductor package by lowering the linear expansion and increasing the elastic modulus of the solder resist film. On the other hand, the content of the filler (B) is, for example, preferably 90% by weight or less, and more preferably 85% by weight or less, based on the total solid content of the thermosetting resin composition. By setting the content of the filler (B) to the upper limit value or less, it becomes possible to more effectively improve the embedding property of the solder resist film.

(Cyanate resin (C))
The thermosetting resin composition may further contain a cyanate resin (C). As a result, the solder resist film can be reduced in linear expansion and improved in elastic modulus and rigidity. It is also possible to contribute to improvement of heat resistance and moisture resistance of the obtained semiconductor device.

The cyanate resin (C) is a resin having a cyanate group (—O—CN) in the molecule, and a resin having two or more cyanate groups in the molecule can be used. Although it does not specifically limit as said cyanate resin (C), For example, dicyclopentadiene type cyanate ester resin, phenol novolak type cyanate ester resin, novolak type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, tetramethyl Examples thereof include bisphenol type cyanate resins such as bisphenol F type cyanate resins, and naphthol aralkyl type cyanate resins.
Moreover, although the said cyanate resin (C) is not specifically limited, For example, it can obtain by making a halogenated cyanide compound, phenols, or naphthol react. Examples of such a cyanate resin include a cyanate resin obtained by a reaction of a phenol novolac type polyhydric phenol and a cyanogen halide, and a reaction of a cresol novolac type polyhydric phenol and a cyanogen halide. Examples include cyanate resins and cyanate resins obtained by reaction of naphthol aralkyl polyvalent naphthols with cyanogen halides. The cyanate resin (C) may be used alone or in combination of two or more.
Among these, from the viewpoint of lowering the linear expansion of the solder resist film and improving the modulus of elasticity and rigidity, it is more likely to contain a phenol novolak type cyanate resin, dicyclopentadiene type cyanate ester resin, or naphthol aralkyl type cyanate resin. It is particularly preferable to include a phenol novolac-type cyanate resin.

The content of the cyanate resin (C) is, for example, preferably 3% by weight or more and more preferably 5% by weight or more with respect to the total solid content of the thermosetting resin composition. By making content of cyanate resin (C) more than the said lower limit, it aims at more effective low linear expansion and high elastic modulus of the soldering resist film formed using a thermosetting resin composition. Can do. Moreover, it can contribute to the improvement of embedding property and smoothness. On the other hand, the content of the cyanate resin (C) is, for example, preferably 40% by weight or less, and more preferably 35% by weight or less, based on the total solid content of the thermosetting resin composition. By making content of cyanate resin (C) below the said upper limit, the heat resistance and moisture resistance of a soldering resist film formed using a thermosetting resin composition can be improved.

(Curing accelerator (D))
It is preferable that the thermosetting resin composition further contains, for example, a curing accelerator (D). Thereby, the sclerosis | hardenability of a thermosetting resin composition can be improved.

As the curing accelerator (D), one that accelerates the curing reaction of the epoxy resin (A) can be used, and the type thereof is not particularly limited. Although it does not specifically limit as a hardening accelerator (D), For example, a zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, zinc octylate, bisacetylacetonate cobalt (II), trisacetylacetonate cobalt Organometallic salts such as (III), tertiary amines such as triethylamine, tributylamine, diazabicyclo [2,2,2] octane, tetraphenylphosphonium tetraphenylborate (TPP-K), tetraphenylphosphonium tetrakis (4 Quaternary phosphonium compounds such as 2-methylphenyl) borate (TPP-MK), 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-ethylimidazole, 2-phenyl- 4-methyl-5-hy From imidazoles such as loxyimidazole and 2-phenyl-4,5-dihydroxyimidazole, phenolic compounds such as phenol, bisphenol A and nonylphenol, organic acids such as acetic acid, benzoic acid, salicylic acid and paratoluenesulfonic acid, and onium salt compounds One or more selected may be included. Among these, it is more preferable to include an onium salt compound from the viewpoint of more effectively improving curability.

Although the onium salt compound used as the curing accelerator (D) is not particularly limited, for example, a compound represented by the following general formula (2) can be used.

(In formula (2), P is a phosphorus atom, R ³ , R ⁴ , R ⁵ and R ⁶ are each an organic group having a substituted or unsubstituted aromatic ring or heterocyclic ring, or a substituted or unsubstituted aliphatic group. Each of which may be the same as or different from each other, and A ⁻ represents an anion of an n-valent proton donor having at least one proton that can be released to the outside of the molecule in the molecule, or Indicates the complex anion)

The content of the curing accelerator (D) is, for example, preferably 0.1% by weight or more, and more preferably 0.3% by weight or more with respect to the total solid content of the thermosetting resin composition. . By making content of a hardening accelerator (D) more than the said lower limit, sclerosis | hardenability of a thermosetting resin composition can be improved more effectively. On the other hand, the content of the curing accelerator (D) is, for example, preferably 10% by weight or less, and more preferably 5% by weight or less, based on the total solid content of the thermosetting resin composition. By making content of a hardening accelerator (D) below the said upper limit, the preservability of a thermosetting resin composition can be improved.

(Colorant (E))
The thermosetting resin composition can further contain, for example, a colorant (E). The colorant (E) includes, for example, one or more selected from dyes such as green, red, blue, yellow, and black, pigments such as black pigments, and dyes. Among these, from the viewpoint of improving the visibility of the opening and the like, a green colorant can be used, but a green dye may be used. The green colorant may include one or more known colorants such as anthraquinone, phthalocyanine, and perylene.

Examples of the black dye include azo-based metal complex black dyes and organic black dyes such as anthraquinone compounds. Although it does not specifically limit as said black dye, For example, Kayase Black AN (made by Nippon Kayaku Co., Ltd.), Kayase Black G (made by Nippon Kayaku Co., Ltd.), etc. are mentioned. In this embodiment, you may use 1 type, or 2 or more types of black pigments.

The lower limit of the content of the black dye is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, based on the total solid content of the thermosetting resin composition. It is particularly preferably 0.07% by weight or more. The marking performance of a laser such as a YAG laser for the solder resist film can be improved. The upper limit of the content of the black dye is preferably 1.0% by weight or less, more preferably 0.9% by weight or less, based on the total solid content of the thermosetting resin composition. More preferably, it is 0.8 wt% or less. This makes it possible to realize a solder resist film colored other than black.

The content of the colorant (E) is, for example, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more based on the total solid content of the thermosetting resin composition. By making content of a coloring agent (E) more than the said lower limit, the visibility and concealment property of the opening part of the soldering resist film obtained using a thermosetting resin composition can be improved more effectively. it can. On the other hand, the content of the colorant (E) is, for example, preferably 5% by weight or less, and more preferably 3% by weight or less based on the total solid content of the thermosetting resin composition. By making content of a coloring agent (E) below the said upper limit, it becomes possible to improve sclerosis | hardenability etc. of a thermosetting resin composition more effectively.

(Other ingredients (F))
In addition to the above components, the thermosetting resin composition includes a coupling agent, a leveling agent, a curing agent, a photosensitizer, an antifoaming agent, an ultraviolet absorber, a foaming agent, an antioxidant, a flame retardant, One or two or more additives selected from ion trapping agents and the like may be added.

Examples of the coupling agent include silane coupling agents such as epoxy silane coupling agents, cationic silane coupling agents, and amino silane coupling agents, titanate coupling agents, and silicone oil type coupling agents. Examples of the leveling agent include acrylic copolymers. The content of the coupling agent is not particularly limited. For example, it may be 0.05 to 5% by weight, further 0.2 to 3% by weight, based on the total solid content of the thermosetting resin composition. Also good.

Examples of the curing agent include phenol resins such as phenol novolak resin, cresol novolak resin, arylalkylene type novolak resin, and the like. The content of the curing agent is not particularly limited. For example, the content of the curing agent is preferably 0.05 to 10% by weight, and preferably 0.2 to 5% by weight with respect to the total solid content of the thermosetting resin composition. More preferably. Examples of the photosensitive agent include photosensitive diazoquinone compounds.

In the present embodiment, the thermosetting resin is a varnish-like resin composition. A resin sheet is obtained by forming a varnish-like thermosetting resin into a film.
Such a resin sheet can be obtained, for example, by subjecting a coating film (resin film) obtained by coating a varnish-like thermosetting resin composition to a solvent removal treatment. The resin sheet can be defined as having a solvent content of 5% by weight or less with respect to the entire thermosetting resin composition. In the present embodiment, the solvent removal treatment can be performed, for example, under conditions of 100 ° C. to 150 ° C. and 1 minute to 5 minutes. This makes it possible to sufficiently remove the solvent while suppressing the curing of the thermosetting resin film.

In this embodiment, the method for forming the thermosetting resin on the carrier substrate is not particularly limited. For example, the resin varnish is prepared by dissolving and dispersing the thermosetting resin in a solvent or the like, and various coater apparatuses are used. Examples thereof include a method in which a resin varnish is applied to a carrier substrate and then dried, and a method in which the resin varnish is spray-coated on a carrier substrate using a spray device and then dried. Among these, the method of drying the resin varnish after applying the resin varnish to the carrier substrate using various coaters such as a comma coater and a die coater is preferable. Thereby, the resin sheet with a carrier base material which has no void and has a uniform resin sheet thickness can be efficiently produced.

(solvent)
In this embodiment, the varnish-like thermosetting resin composition can contain a solvent, for example.
Examples of the solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, cyclohexane, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve, carbitol, anisole, And one or more selected from organic solvents such as N-methylpyrrolidone.

When the thermosetting resin composition is varnished, the solid content of the thermosetting resin composition is preferably, for example, 30% by weight to 80% by weight, and preferably 40% by weight to 70% by weight. It is more preferable that Thereby, the thermosetting resin composition excellent in workability | operativity and film formability is obtained. In addition, the varnish-like thermosetting resin composition includes, for example, the above-described components, an ultrasonic dispersion method, a high-pressure collision dispersion method, a high-speed rotation dispersion method, a bead mill method, a high-speed shear dispersion method, and a rotation and revolution dispersion method. It can prepare by melt | dissolving, mixing, and stirring in a solvent using various mixers.

In addition, the thermosetting resin composition according to the present embodiment may not include a fiber substrate such as a glass fiber substrate or a paper substrate. Thereby, it is possible to realize a thermosetting resin composition particularly suitable for forming a solder resist film.

[Resin sheet]
The resin sheet can include a film obtained from the thermosetting resin composition. In this embodiment, the resin sheet may have a sheet shape or a roll shape that can be wound. A solder resist film can be obtained by curing the resin sheet. Moreover, you may obtain a soldering resist film by hardening the coating film of the said thermosetting resin composition.

In this embodiment, when the thermosetting resin composition is heat-treated at 200 ° C. for 1 hour to obtain a cured product, the storage elastic modulus at 25 ° C. of the cured product of the thermosetting resin composition is 7 GPa. The above is preferable. As a result, it is possible to suppress deflection and improve the strength of a printed wiring board provided with a resin sheet obtained using the thermosetting resin composition, suppress warpage of a semiconductor package provided with this printed wiring board, and the like. The storage elastic modulus is more preferably 10 GPa or more. On the other hand, the upper limit value of the storage elastic modulus is not particularly limited, but may be, for example, 50 GPa or less. Thereby, the printed wiring board 20 which can manufacture the package excellent in durability can be implement | achieved more reliably.

In this embodiment, when the thermosetting resin composition is heat-treated at 200 ° C. for 1 hour to obtain a cured product, the glass transition temperature of the cured product of the thermosetting resin composition is 160 ° C. or higher. Preferably there is. Thereby, it becomes possible to improve the heat resistance and reflow resistance of the resin sheet obtained using the thermosetting resin composition. The glass transition temperature is more preferably 200 ° C. or higher. On the other hand, the upper limit value of the glass transition temperature is not particularly limited, but can be, for example, 350 ° C. or lower.

In the present embodiment, the storage elastic modulus and the glass transition temperature are determined based on the dynamic viscosity of the cured product, for example, using a dynamic viscoelasticity measuring device at a frequency of 1 Hz and a heating rate of 5 ° C./min. It can be calculated from a measurement result obtained by performing an elasticity test. Although it does not specifically limit as a dynamic viscoelasticity measuring apparatus, For example, the Seiko Instruments make and DMS6100 can be used.

In this embodiment, when the thermosetting resin is heat treated at 200 ° C. for 1 hour to obtain a cured product, the linear expansion coefficient of the cured product of the thermosetting resin composition below the glass transition temperature is It is preferably 30 ppm / ° C. or less. Thereby, it becomes possible to suppress warpage of a semiconductor package including a resin sheet obtained using the thermosetting resin composition. The linear expansion coefficient is more preferably 28 ppm / ° C. or less. On the other hand, the lower limit value of the linear expansion coefficient is not particularly limited, but can be, for example, 3 ppm / ° C. or more. Thereby, the printed wiring board 20 which can manufacture the package excellent in durability can be implement | achieved more reliably.
In the present embodiment, for example, the linear expansion coefficient obtained by measuring the cured product using a TMA (thermal analyzer) at a temperature increase rate of 10 ° C./min at 25 to 50 ° C. An average can be calculated and used as the linear expansion coefficient below the glass transition temperature.

In the present embodiment, for example, by appropriately selecting the type and blending amount of each component contained in the thermosetting resin composition, the preparation method of the thermosetting resin composition, etc., the storage elastic modulus, the above It is possible to control the glass transition temperature and the linear expansion coefficient.

Further, by arranging the resin sheet (resin film) of this embodiment on a carrier substrate, a resin sheet with a carrier substrate can be configured. Thereby, the handleability of the resin sheet can be improved.

In the present embodiment, for example, a polymer film or a metal foil can be used as the carrier substrate. The polymer film is not particularly limited. For example, polyolefin such as polyethylene and polypropylene, polyester such as polyethylene terephthalate and polybutylene terephthalate, release paper such as polycarbonate and silicone sheet, heat resistance such as fluorine resin and polyimide resin. A thermoplastic resin sheet having The metal foil is not particularly limited. For example, copper and / or a copper-based alloy, aluminum and / or an aluminum-based alloy, iron and / or an iron-based alloy, silver and / or a silver-based alloy, gold and a gold-based alloy, for example. Zinc and zinc-based alloys, nickel and nickel-based alloys, tin and tin-based alloys, and the like. Among these, a sheet made of polyethylene terephthalate is most preferable because it is inexpensive and easy to adjust the peel strength. Thereby, it becomes easy to peel from the said resin sheet with moderate intensity | strength.
The thickness of the carrier base material is not particularly limited, but may be, for example, 10 to 100 μm or 10 to 70 μm. Thereby, the handleability at the time of manufacturing a resin sheet is favorable and preferable.

The above resin sheet may be a single layer or multiple layers, and may contain one or more of the above films. When the said resin sheet is a multilayer, it may be comprised by the same kind and may be comprised by different types.

In the present embodiment, the method of forming the resin sheet having two or more layers is not particularly limited. For example, the first resin layer and the second resin obtained by applying a thermosetting resin composition to a carrier substrate. A two-layer resin sheet is obtained by bonding the layers together and then drying them. In addition, a 1st resin sheet is obtained by apply | coating a thermosetting resin composition to a carrier base material, and making it dry. Then, the method of forming a 2nd resin sheet on a 1st resin sheet by apply | coating a thermosetting resin composition on a 1st resin sheet, and even drying is mentioned. Moreover, the method of obtaining the resin sheet of 2 layers can also be used by apply | coating and drying two layers on a carrier base material simultaneously.

As described above, the embodiments of the present invention have been described with reference to the drawings. However, these are exemplifications of the present invention, and various configurations other than the above can be adopted.

Next, examples of the present invention will be described. In addition, this invention is not limited to the Example described below.

Example 1
[1] Preparation of thermosetting resin composition 14.5% by mass of a naphthalene-modified cresol novolac type epoxy resin (manufactured by DIC Corporation, HP-5000) as an epoxy resin, and a phenol novolac type cyanate ester resin (manufactured by LONZA) as a cyanate resin PT-30) 14.5% by mass, spherical silica particles (manufactured by Admatechs Co., Ltd., SO-C4, average particle size 1.0 μm, phenylaminosilane treatment) 70% by mass, tetraphenylphosphonium Tetrakis (4-methylphenyl) borate (TPP-MK) 0.5 mass% and epoxysilane (KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 mass% as a coupling agent were dissolved and dispersed in methyl ethyl ketone. Then, it stirred for 1 hour using the high-speed stirring apparatus. Thereby, a varnish-like thermosetting resin composition was obtained.

[2] Production of Insulating Resin Film with Metal Film The resin varnish prepared in the above [1] was applied on a PET film as a carrier substrate. Thereafter, the resin varnish on the PET film was dried at 140 ° C. for 2 minutes to remove the solvent, and a resin sheet with a carrier base material (insulating resin film) having a resin sheet thickness of 30 μm was obtained.
Next, a peelable metal foil in which a copper foil having a thickness of 3 μm (manufactured by Mitsui Mining & Smelting Co., Ltd., MT18SD-H), a release layer, and a carrier foil were laminated in this order was prepared. This peelable metal foil was placed on a resin sheet with a carrier substrate so that the copper foil faced the insulating resin film. Thereafter, the metal foil is thermocompression bonded to the resin sheet, the release layer and the carrier foil are peeled off, and the insulating resin with a metal film comprising a copper foil (metal film) and an insulating resin film is formed on the carrier substrate. A membrane was obtained. The surface roughness of the surface of the copper foil facing the insulating resin film was measured using a laser microscope (manufactured by Keyence Corporation, VK-X100). As a result, the 10-point average roughness Rz was 3.0 μm.

[3] Fabrication of structure A copper-clad laminate (manufactured by Sumitomo Bakelite Co., Ltd., LαZ4785GS-B) in which copper foil was laminated on both surfaces of the core substrate was prepared. The copper foil on one surface of the copper clad laminate was patterned by etching to form a conductor pattern, and the copper foil on the other surface of the copper clad laminate was all removed by etching. This produced the core substrate by which the conductor pattern was provided in one surface.
Next, the insulating resin film of the insulating resin film with a metal film produced in the above [2] is opposed to the surface on which the conductor pattern of the core substrate is provided, and a temperature is measured using a vacuum pressure laminator device. After vacuum heating and pressure molding at 100 ° C. and a pressure of 1 MPa, drying was performed for 60 minutes with a drying apparatus at 180 ° C. Thereafter, by removing the carrier base material, a structure in which the core substrate, the insulating resin film, and the metal film were laminated in this order was produced.

[4] Formation of Opening in Metal Film Next, etching is performed on the metal film of the structure to open a predetermined area of the metal film (area corresponding to the land of the conductor pattern on the core substrate). Part was formed.

[5] Formation of opening in insulating resin film Next, the insulating resin film is etched by a laser processing method using the metal film having the opening as a mask, and the land on the core substrate is formed. An opening was formed in the insulating resin film so as to be exposed. Thereafter, the structure was heated with a drying apparatus at 220 ° C. for 60 minutes to cure the B-stage insulating resin film to form a solder resist film.
Next, the structure was immersed in a swelling solution at 60 ° C. (Atotech Co., Swelling Dip Securigant P) for 5 minutes, and further added to an aqueous potassium permanganate solution (Atotech Co., Concentrate Compact CP) at 80 ° C. After the minute immersion, the desmear treatment was performed by neutralization.

[6] Removal of Metal Film Next, flash etching was performed on the metal film of the structure to remove the metal film on the surface of the solder resist film.

[7] Plating treatment Next, a plating layer was formed on the conductor pattern (land) exposed in the opening of the solder resist film. Specifically, an electroless nickel plating layer of 3 μm was formed, and an electroless gold plating layer of 0.1 μm was further formed thereon. Thereby, a printed wiring board was obtained.

(Example 2)
Example 3 was used except that a 3 μm thick copper foil (Mitsui Metals Co., Ltd., MT18Ex) was used instead of a 3 μm thick copper foil (Mitsui Metals Co., Ltd., MT18SD-H). A wiring board was obtained.
The surface roughness of the surface of the copper foil facing the insulating resin film was measured using a laser microscope (manufactured by Keyence Corporation, VK-X100). As a result, the 10-point average roughness Rz was 2.0 μm.

(Example 3)
Example except that 3 μm thick copper foil (Mitsui Metal Mining Co., Ltd., MT18SD-H-T3B) was used instead of 3 μm thick copper foil (Mitsui Metal Mining Co., Ltd., MT18SD-H) In the same manner as in No. 1, a wiring board was obtained.
The surface roughness of the surface of the copper foil facing the insulating resin film was measured using a laser microscope (manufactured by Keyence Corporation, VK-X100). As a result, the 10-point average roughness Rz was 1.8 μm.

Example 4
Example 1 was used except that a 3 μm thick copper foil (Furukawa Electric Co., Ltd., F-HP) was used instead of the 3 μm thick copper foil (Mitsui Metal Mining Co., Ltd., MT18SD-H). A wiring board was obtained in the same manner.
The surface roughness of the surface of the copper foil facing the insulating resin film was measured using a laser microscope (manufactured by Keyence Corporation, VK-X100). As a result, the 10-point average roughness Rz was 1.5 μm.

(Example 5)
Example 3 was used except that a 3 μm thick copper foil (Mitsui Metal Mining Co., Ltd., MT18FL) was used instead of a 3 μm thick copper foil (Mitsui Metal Mining Co., Ltd., MT18SD-H). A wiring board was obtained.
The surface roughness of the surface of the copper foil facing the insulating resin film was measured using a laser microscope (manufactured by Keyence Corporation, VK-X100). As a result, the 10-point average roughness Rz was 1.3 μm.

(Example 6)
Example 1 except that a 18 μm thick copper foil (HS-GHY5, manufactured by JX Metals, Inc.) was used instead of a 3 μm thick copper foil (Mitsui Metals, Ltd., MT18SD-H). Thus, a wiring board was obtained.
The surface roughness of the surface of the copper foil facing the insulating resin film was measured using a laser microscope (manufactured by Keyence Corporation, VK-X100). As a result, the 10-point average roughness Rz was 0.3 μm.

(Comparative example)
Instead of the insulating resin film with a metal film, a resin sheet with a carrier substrate prepared in the same manner as in Example 1 was prepared.
Thereafter, a structure was produced in the same manner as [3] in Example 1. Thereafter, the insulating resin film was directly etched by laser irradiation to form openings in the insulating resin film so that the lands on the core substrate were exposed. Thereafter, the structure was heated with a drying apparatus at 220 ° C. for 60 minutes to cure the B-stage insulating resin film to form a solder resist film.
Thereafter, in the same manner as in [7] of Example 1, a plating layer was formed on the conductor pattern (land) exposed at the opening of the solder resist film to obtain a printed wiring board.

(Evaluation of surface smoothness of solder resist film)
For the printed wiring boards of the examples and comparative examples, the surface roughness (10-point average roughness Rz) of the solder resist film was measured using a laser microscope (manufactured by Keyence Corporation, VK-X100). Evaluated according to. The results are shown in Table 1.
A: 10-point average roughness Rz is 0.2 μm or more and 1.8 μm or less.
B: The 10-point average roughness Rz is larger than 1.8 μm and 2.0 μm or less.
C: The 10-point average roughness Rz is larger than 2.0 μm and not larger than 3.0 μm.
D: The 10-point average roughness Rz is larger than 3.0 μm.

(State observation around the opening of the solder resist film)
About the wiring board of each Example and a comparative example, the opening part periphery formed by laser irradiation was observed with the laser microscope, and it evaluated according to the following references | standards. The results are shown in Table 1.
A: No laser burn was observed in the solder resist film around the opening.
B: Laser burn was observed in the solder resist film around the opening.

As shown in Table 1, in the printed wiring board of each example, there was no laser burn on the solder resist film around the opening. On the other hand, in the printed wiring board of the comparative example, laser burn was observed in the solder resist film around the opening. From these evaluation results, it was found that the printed wiring board of each example can form a fine and precise opening in the solder resist film as compared with the comparative example in which the opening is formed by direct laser irradiation.

Furthermore, in Examples 2 to 6, the surface smoothness of the solder resist film was particularly excellent. When the printed wiring boards of Examples 2 to 6 were inspected with an ultrasonic microscope, it was found that bubbles were difficult to adhere to the solder resist film of each printed wiring board, so that the accuracy of inspection for peeling and cracking was improved. .

According to the method for manufacturing a printed wiring board of the present invention, a fine and precise opening is formed in a solder resist layer by using a metal film as a mask instead of a resist film formed of a thermosetting resin. A printed wiring board can be provided. By using such a printed wiring board, the productivity of the semiconductor device can be improved. Therefore, the present invention has industrial applicability.

Claims

Preparing a structure in which a circuit board having a circuit surface provided with a circuit, a solder resist film, and a metal film are laminated in this order;
Forming a first opening in the metal film by selectively removing the metal film;
Removing the solder resist film in the region where the first opening is formed to form a second opening in the solder resist layer to expose a part of the circuit;
Removing the metal film to expose the surface of the solder resist film;
A method for producing a printed wiring board, comprising:
The metal film has a smooth surface with a surface roughness Rz of 0.1 μm to 3.0 μm,
2. The wiring board according to claim 1, wherein one surface of the solder resist film is disposed to face the smooth surface of the metal film, and the other surface of the solder resist film is disposed to face the circuit surface of the circuit board. Manufacturing method.
The step of preparing the structure includes
Preparing the solder resist film in which the metal film is disposed so that the smooth surface of the metal film faces the one surface of the solder resist film;
The manufacturing method of the printed wiring board of Claim 2 including the process of preparing the said structure by making the said other surface of the said soldering resist film and the said circuit surface of the said circuit board oppose and bonding together.
The step of preparing the structure includes
Preparing the solder resist film in which the carrier base material is arranged so that the main surface of the carrier base material faces the one surface of the solder resist film;
The other surface of the solder resist film and the circuit surface of the circuit board are opposed to each other and bonded together;
The carrier substrate is peeled from the solder resist film, and the metal film having the smooth surface is formed on the one surface of the solder resist film. Production method.
The method for manufacturing a printed wiring board according to any one of claims 1 to 4, wherein a thickness of the solder resist film is 10 µm or more and 50 µm or less.
In the step of preparing the structure, the solder resist film is in a B stage state,
The method for manufacturing a printed wiring board according to claim 1, further comprising a step of curing the solder resist film after forming the second opening.
The method for manufacturing a printed wiring board according to any one of claims 1 to 6, wherein a thickness of the metal film is 1 µm or more and 30 µm or less.
The method for manufacturing a printed wiring board according to any one of claims 2 to 7, wherein the metal film includes a non-roughened copper foil.
The method for producing a printed wiring board according to any one of claims 1 to 8, wherein the solder resist film is in a sheet form.
The solder resist film is formed using a resin composition for solder resist,
The method for manufacturing a printed wiring board according to any one of claims 1 to 9, wherein the solder resist resin composition includes a thermosetting resin and an inorganic filler.
The method for producing a printed wiring board according to claim 10, wherein the thermosetting resin includes an epoxy resin having a naphthalene skeleton.
The method for producing a printed wiring board according to claim 10 or 11, wherein the solder resist resin composition contains a colorant.
A step of preparing a printed wiring board obtained by the method for manufacturing a printed wiring board according to any one of claims 1 to 12,
Mounting a semiconductor element on the printed wiring board.