WO2020144861A1

WO2020144861A1 - Metal-clad layered plate production method, metal-clad layered plate, printed circuit board and semiconductor package, and coreless base board forming support and semiconductor re-wiring layer forming support

Info

Publication number: WO2020144861A1
Application number: PCT/JP2019/000741
Authority: WO
Inventors: 貴代北嶋; 昌久尾瀬; 広明藤田
Original assignee: 日立化成株式会社
Priority date: 2019-01-11
Filing date: 2019-01-11
Publication date: 2020-07-16
Also published as: KR20210113229A; JPWO2020144861A1; CN113272131A; JP7351315B2

Abstract

Provided are a metal-clad layered plate having excellent plate thickness accuracy and a production method therefor. In addition, provided are a printed circuit board yielded by forming a circuit on the metal-clad layered plate, and a semiconductor package yielded by mounting a semiconductor element on the printed circuit board. In addition, provided are a coreless baseboard forming support including the metal-clad layered plate, and a semiconductor re-wiring layer forming support. The metal-clad layered plate production method specifically comprises: (1) a step of grinding at least one of the surfaces of a cured product from a prepreg containing a thermosetting resin composition and a base material; and (2-1) a step of layering, on the surface that has been ground in the step (1), a metallic foil to form a metal-clad layered plate, or (2-2) a step of layering, on the surface that has been ground in the step (1), a metallic foil and a thermosetting resin film or a metallic foil-attached thermosetting resin film, in such a manner that the thermosetting resin film is on the ground surface side, to form the metal-clad layered plate.

Description

Method for manufacturing metal-clad laminate, metal-clad laminate, printed wiring board and semiconductor package, support for coreless substrate formation, and support for semiconductor rewiring layer formation

The present invention relates to a method for manufacturing a metal-clad laminate, a metal-clad laminate, a printed wiring board and a semiconductor package, a support for coreless substrate formation and a support for semiconductor rewiring layer formation.

2. Description of the Related Art In recent years, as electronic devices have become higher in density, miniaturization, weight reduction, and multi-functionalization have been further advanced. As a result, the density of printed circuit boards and semiconductor packages on which LSI (Large Scale Integration) is mounted have also been increased. High reliability is required. Due to this, the demand for improving the plate thickness accuracy of metal-clad laminates is becoming stricter.
A metal-clad laminate obtained by sandwiching a plurality of prepregs with a metal foil and laminate-forming by press forming or the like is used as a core substrate of a printed wiring board (for example, see paragraph [0057] of Patent Document 1). Surface undulation occurs after press molding due to the influence of the base material such as glass cloth existing in the above. In the past, this degree of surface waviness was within the allowable range, but there is a tendency for the plate thickness accuracy of the metal-clad laminate to be achieved at a higher level in order to achieve higher density and higher reliability. It has become necessary to solve the problem of reduction in plate thickness accuracy due to the surface waviness.
In addition, the plate thickness accuracy tends to depend on the fluidity of the resin composition, and as shown in FIG. 7, a metal-clad laminate obtained by laminate molding such as press molding (before being cut to a predetermined size In general, the resin composition layer at the end of the so-called press panel) becomes thin, and from the viewpoint of plate thickness accuracy, the portion where the resin composition layer became thin had to be discarded. On the other hand, a method of highly filling an inorganic filler in order to reduce the fluidity of the resin composition is known, but there is a limit to the effect of improving the plate thickness accuracy, and the inorganic filler is highly filled. When is essential, there is a problem that workability such as drill workability is unavoidably deteriorated.

Japanese Patent Laid-Open No. 2016-056371

Therefore, an object of the present invention is to provide a metal-clad laminate excellent in plate thickness accuracy and a manufacturing method thereof. A further object of the present invention is to provide a printed wiring board having a circuit formed on the metal-clad laminate, a semiconductor package having a semiconductor element mounted on the printed wiring board, and a coreless substrate containing the metal-clad laminate. It is to provide a support for formation and a support for forming a semiconductor redistribution layer.

As a result of intensive research to solve the above problems, the inventors of the present invention have at least one of a cured product of prepreg obtained by a method such as etching and removing a metal foil of a metal-clad laminate obtained by press molding. The inventors have found that the above problems can be solved by polishing the surface of the above, and have completed the present invention. The present invention has been completed based on such findings.

The present invention relates to the following [1] to [15].
[1] (1) A step of polishing at least one surface of a cured product of a prepreg containing a thermosetting resin composition and a substrate,
(2-1) A step of laminating a metal foil on the surface polished in the step (1) to form a metal-clad laminate,
And a method for producing a metal-clad laminate.
[2] (1) A step of polishing at least one surface of a cured product of a prepreg containing a thermosetting resin composition and a substrate,
(2-2) A metal foil and a thermosetting resin film or a thermosetting resin film with a metal foil is provided on the surface polished in the step (1), and the thermosetting resin film is on the polished surface side. Laminating to form a metal-clad laminate,
And a method for producing a metal-clad laminate.
[3] The method for producing a metal-clad laminate according to the above [1] or [2], wherein both surfaces of the cured product of the prepreg are polished in the step (1).
[4] The method for producing a metal-clad laminate according to any one of the above [1] to [3], wherein the thickness of the cured product of the prepreg is made substantially uniform by the polishing in the step (1).
[5] Any of [1] to [4] above, wherein the cured product of the prepreg is obtained by etching away the metal foil of the metal-clad laminate in which the surface of the cured product inside is not polished. A method for producing a metal-clad laminate as described in 1.
[6] The size of the largest surface area of the cured product of the prepreg is 200 mm to 1,300 mm in length×200 mm to 1,300 mm in width, and within 70 mm from the end of the cured product of the prepreg. The method for producing a metal-clad laminate according to any one of the above [1] to [5], wherein at least a part of the thickness of the cured product is smaller than the thickness of the central part of the cured product.
[7] Manufacturing of the metal-clad laminate according to any one of [1] to [6] above, wherein in the step (1), the entire surface is polished until the thickness of the thinnest part of the cured product of the prepreg becomes uniform. Method.
[8] In the step (1), (i) CMP (Chemical mechanical polishing) method, (ii) mechanical polishing such as fly-cutting, grinding, sandblasting, belt polishing, and scrubbing, (iii) persulfate, peroxide The method for producing a metal-clad laminate according to any one of the above [1] to [7], wherein polishing is performed by a method selected from the group consisting of hydrogen-sulfuric acid mixture, chemical polishing using inorganic acid, organic acid and the like. ..
[9] The method for producing a metal-clad laminate according to any one of [1] to [8] above, wherein the difference between the maximum value and the minimum value of the thickness of the obtained metal-clad laminate is 20 μm or less.
[10] A metal-clad laminate obtained by the method according to any one of [1] to [9] above.
[11] (a) A cured product of a prepreg containing a thermosetting resin composition and a substrate, wherein the cured product has at least one surface polished, and (b) a substrate. A metal-clad laminate comprising a thermosetting resin composition layer, and (c) a metal foil.
[12] A printed wiring board containing the metal-clad laminate according to the above [10] or [11].
[13] A semiconductor package in which a semiconductor element is mounted on the printed wiring board according to [12].
[14] A support for forming a coreless substrate, containing the metal-clad laminate according to the above [10] or [11].
[15] A support for forming a semiconductor redistribution layer, comprising the metal-clad laminate according to the above [10] or [11].

According to the present invention, it is possible to provide a metal-clad laminate excellent in plate thickness accuracy and a method for manufacturing the same. Further, a printed wiring board formed by forming a circuit on the metal-clad laminate, a semiconductor package in which a semiconductor element is mounted on the printed wiring board, and a support for coreless substrate formation containing the metal-clad laminate, A support for forming a semiconductor redistribution layer can be provided.
According to the method of the present invention, a metal-clad laminate having excellent plate thickness accuracy can be obtained without highly filling with an inorganic filler, so that the metal-clad laminate with good workability can be obtained.

It is a conceptual diagram which shows an example of the embodiment of the manufacturing method of this invention. It is a conceptual diagram which shows an example of the embodiment of the manufacturing method of this invention. It is a conceptual diagram which shows an example of the manufacturing process of the coreless board using the support for coreless board formation of the present invention. The figure which shows the result of having measured the surface roughness (Ra) about the surface of the laminated body used in Example 1 before polishing by using a highly accurate three-dimensional surface shape roughness measurement system (Veeco Instruments, Wyko NT9100). Is. The surface roughness (Ra) of the surface of the cured product of the prepreg after polishing obtained in Example 1 was measured using a high-accuracy three-dimensional surface shape roughness measuring system (Veeco Instruments, Wyko NT9100). FIG. 3 is a digital microscope image of a cross section of the copper clad laminate A obtained in Example 1. It is a conceptual diagram which shows a mode that the thickness of the edge part of a resin composition layer becomes thin, when press-molding and manufacturing a metal-clad laminated board (press panel).

In the numerical ranges described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples. The lower limit value and the upper limit value of the numerical range are arbitrarily combined with the lower limit value and the upper limit value of the other numerical range.
Further, each component and material exemplified in the present specification may be used alone or in combination of two or more unless otherwise specified.
The present invention also includes embodiments in which the items described in this specification are arbitrarily combined.

[Method of manufacturing metal-clad laminate]
One aspect of the method for producing a metal-clad laminate of the present invention,
(1) A step of polishing at least one surface of a cured product of a prepreg containing a thermosetting resin composition and a substrate [hereinafter, sometimes referred to as step (1)],
(2-1) A step of laminating a metal foil on the surface polished in the step (1) to form a metal-clad laminate [hereinafter, sometimes referred to as step (2-1)],
And a method for producing a metal-clad laminate.

Another aspect of the method for producing a metal-clad laminate of the present invention is,
(1) A step of polishing at least one surface of a cured product of a prepreg containing a thermosetting resin composition and a substrate,
(2-2) A metal foil and a thermosetting resin film or a thermosetting resin film with a metal foil is provided on the surface polished in the step (1), and the thermosetting resin film is on the polished surface side. A step of forming a metal-clad laminate by laminating so that [hereinafter, referred to as step (2-2)],
And a method for producing a metal-clad laminate.
Hereinafter, the step (1) will be described in detail with reference to FIG. 1 or FIG. 2 as necessary.

<Step (1)>
The step (1) is a step of polishing at least one surface of the cured product 1 of the prepreg containing the thermosetting resin composition 6 and the base material 7. Here, in the present invention, the cured product of the prepreg means a state in which the thermosetting resin composition contained in the prepreg is C-staged, and the state in which the thermosetting resin composition is B-staged. Not included. Further, "at least one surface of the cured product 1 of the prepreg" means at least one of the two surfaces having the largest area in the cured product 1 of the prepreg, and the surface in the thickness direction (lateral surface). Is not included. However, in addition to "at least one surface of the cured product 1 of the prepreg", polishing the surface (lateral surface) in the thickness direction is not denied.
The hardened material 1 of the prepreg used in the step (1) can be obtained by etching away the metal foil of the metal-clad laminate in which the surface of the inner hardened material is not polished. In other words, the metal-clad laminate obtained by arranging the metal foil on one side or both sides of one or more prepregs and performing laminate molding such as press molding has surface waviness, and the plate thickness accuracy is not sufficient. Therefore, by removing the metal foil from the metal-clad laminate by etching and performing the step (1), the surface waviness is eliminated, which leads to the formation of a metal-clad laminate having high plate thickness accuracy.
Here, the surface waviness is undulations repeated at intervals larger than the surface roughness. In the present invention, as shown in FIG. 4 in which the surface was observed under the conditions described in the examples using a high-precision three-dimensional surface roughness measuring system, as shown in FIG. 4, a wide range of X axis: 95 μm and Y axis: 95 μm (however, When the surface roughness (arithmetic mean roughness: Ra) is 1.0 μm or less and the surface roughness is more than 1.0 μm, the surface waviness is said to be large. The plate thickness accuracy is low. It can be said that the greater the surface roughness at the surface roughness (Ra) of more than 1.0 μm (for example, 1.5 μm or more, 2.0 μm or more), the greater the surface waviness. Since the surface waviness is eliminated in the present invention, when the surface roughness is observed using the high precision three-dimensional surface shape roughness measuring system, the surface roughness is 1.0 μm or less in the entire surface area of the cured product of the prepreg. And is preferably 0.9 μm or less, more preferably 0.8 μm or less.

There is no particular limitation on the method for etching away the metal foil of the metal-clad laminate in which the surface of the cured product inside is not polished, and a general etching removal method for the metal foil of the metal-clad laminate used in the production of printed wiring boards. Can be adopted. For example, the metal foil can be removed by etching using ferric chloride solution, ammonium persulfate, or the like.
A commercially available metal-clad laminate can be used as the metal-clad laminate whose surface of the cured product inside is not polished, or can be produced by a known method. As a method for producing, for example, a prepreg containing a thermosetting resin composition and a base material, or a plurality of (for example, 2 to 20) prepregs are stacked, and a metal foil is arranged on one side or both sides of the prepreg. A cured product obtained by laminating and molding can also be used. The thermosetting resin composition and the base material will be described later. The lamination molding conditions are not particularly limited, but for example, using a multi-stage press, multi-stage vacuum press, continuous molding, autoclave molding machine, etc., a temperature of 100 to 250° C., a pressure of 0.2 to 10 MPa, The heating time may be 0.1 to 5 hours.

Examples of the metal foil of the metal-clad laminate in which the surface of the cured product inside is not polished include copper foil, nickel foil, aluminum foil and the like, and among these, copper foil is preferable. The thickness of the metal foil is not particularly limited, but is preferably 0.5 to 150 μm, more preferably 1 to 100 μm, further preferably 5 to 50 μm, particularly preferably 5 to 30 μm, and most preferably 7 to 18 μm.

The surface 2 to be polished may be at least one surface of the cured product, but it is preferable to polish both surfaces of the cured product from the viewpoint of sufficiently eliminating the surface waviness and enhancing the plate thickness accuracy. Here, "at least one surface of the cured product" means at least one of the two surfaces having the largest area in the cured product, and does not include the surface in the thickness direction (lateral surface). In addition, "the both surfaces of the cured product" means the two surfaces having the largest area in the cured product, and does not include the surface in the thickness direction (horizontal surface). However, in addition to “both sides of the cured product”, polishing the surface in the thickness direction (lateral surface) is not denied.
From the viewpoint of sufficiently eliminating the surface waviness and enhancing the plate thickness accuracy, it is preferable to polish the entire surface to be polished.
The size of the cured product 1 of the prepreg is not particularly limited, but as the size of the metal-clad laminate (that is, a so-called press panel before being cut into a predetermined size) obtained by press molding, the surface having the largest area can be used. More preferably, the size is 200 mm to 1,300 mm in length×200 mm to 1,300 mm in width. Further, in the cured product of the prepreg, for example, at least a part of the thickness of the cured product of the prepreg within the range of 70 mm from the end (or within the range of 50 mm from the end) is the thickness of the central part 3 of the cured product. It can be used even if there is a thin portion 4 as compared with. Here, the "range within 70 mm from the end of the cured product of the prepreg" means when measured from any end of the cured product of the prepreg toward the inside of the cured product and perpendicularly to the end. It means within a range of 70 mm.

The method for polishing the surface of the cured product is not particularly limited, but (i) CMP (Chemical mechanical polishing) method, (ii) mechanical polishing such as fly-cut, grind, sandblast, belt polishing, scrub polishing, etc., (iii) excess polishing Polishing is preferably carried out by a method selected from the group consisting of sulfates, hydrogen peroxide-sulfuric acid mixtures, chemical polishing using inorganic acids, organic acids and the like. Among these, polishing by the CMP method, fly cutting and grinding is more preferable. As the polishing method, one type may be used alone, or two or more types may be used in combination.
By the polishing, the surface waviness of the surface of the polished cured product is reduced, and the surface roughness (Ra) of the surface is preferably 1.0 μm or less, more preferably 0.9 μm or less, and further preferably 0.8 μm or less. Become. In the present invention, the surface roughness (Ra) can be measured using a stylus-type surface profile measuring instrument (trade name “DektakXT” manufactured by Bruker Corporation).
The CMP method is mechanical polishing with a chemical etching action by an alkaline polishing solution. When the CMP method is used, it is not particularly limited, but for example, “Maro Ohta, two others, “Optical end point monitor for oxide film CMP”, [online], Ebara Jikkan, No. 207. (2005-4), [June 12, 2018 search], Internet, <URL:https://www.ebara.co.jp/about/technologies/abstract/detail/__icsFiles/afieldfile/2016/04/ 25/207_P25.pdf>” can be used. Further, as the mechanical polishing, for example, fly cutting is not particularly limited, but a grinding device with a diamond bite, for example, an automatic surface planer for a 300 mm wafer (manufactured by DISCO Corporation, product name “DAS8930”), This is a method of physically grinding (polishing) using a grinder (trade name “DFG8540” and “DFG8560” manufactured by DISCO Corporation).

By the step (1), the surface waviness of the cured product of the prepreg can be eliminated and the plate thickness accuracy can be improved. It can be said that the cured product has a substantially uniform thickness. Here, the term “approximately uniformized” includes not only a mode in which the thickness is completely uniformed, but also a mode in which the thickness is uniformed to such an extent that the surface waviness falls within the above range even if it is not completely uniform.
Further, as shown in FIGS. 1 and 2, it is preferable that in the polishing, the entire surface is polished until the thickness of the thinnest portion 5 in the cured product of the prepreg is adjusted. Here, "equal to the thickness of the thinnest part 5 in the cured product of the prepreg" means that the thickness of the entire prepreg is substantially uniform. By polishing in this manner, the thickness of the entire cured product is made substantially uniform, and it is not necessary to discard the portion where the cured product is thin. At the time of polishing, even if the base material in the prepreg is polished, there is no particular problem, but the base material may be polished while being adjusted so as not to polish the base material.

(Thermosetting resin composition)
The thermosetting resin composition contained in the prepreg is not particularly limited as long as it contains a thermosetting resin. As the thermosetting resin, for example, epoxy resin, phenol resin, unsaturated imide resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, silicone resin, modified Examples include silicone resins, triazine resins, melamine resins, urea resins, furan resins and the like. In addition, known thermosetting resins can be used without particular limitation. These may be used alone or in combination of two or more. Among these, epoxy resin, unsaturated imide resin, and modified silicone resin are preferable.

The epoxy resin is not particularly limited, but for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin or other bisphenol type epoxy resin; alicyclic epoxy resin; aliphatic chain Epoxy resin; novolac type epoxy resin such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin; phenol aralkyl type epoxy resin; stilbene type epoxy resin; dicyclopentadiene Type epoxy resin; naphthalene skeleton-containing epoxy resin such as naphthol novolac type epoxy resin and naphthol aralkyl type epoxy resin; biphenyl type epoxy resin; biphenyl aralkyl type epoxy resin; xylylene type epoxy resin; dihydroanthracene type epoxy resin. From these, a naphthalene skeleton-containing epoxy resin may be selected, or a naphthol aralkyl epoxy resin may be selected.

Examples of the unsaturated imide resin include a maleimide resin, an addition reaction product of a maleimide resin and a monoamine compound, a reaction product of a maleimide resin, a monoamine compound and a diamine compound, and the like. The maleimide compound is not particularly limited, and examples thereof include bis(4-maleimidophenyl)methane, polyphenylmethanemaleimide, bis(4-maleimidophenyl)ether, 3,3′-dimethyl-5,5. '-Diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, m-phenylene bismaleimide, bis(4-maleimidophenyl) sulfone, bis(4-maleimidophenyl) sulfide, bis (4-maleimidophenyl)ketone, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, bis(4-(4-maleimidophenoxy)phenyl)sulfone, 4,4'-bis(3-maleimide Examples thereof include phenoxy)biphenyl and 1,6-bismaleimide-(2,2,4-trimethyl)hexane. Of these, bis(4-maleimidophenyl)methane may be selected.
The above-mentioned monoamine compound is preferably a monoamine compound having an acidic substituent (eg, hydroxyl group, carboxy group, etc.), specifically, o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid. , M-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, 3,5-dicarboxyaniline, etc. Can be mentioned.
As the diamine compound, a diamine compound having at least two benzene rings is preferable, and a diamine compound having at least two benzene rings in a straight chain between two amino groups is more preferable, and 4,4′-diamino is preferred. Diphenylmethane, 4,4'-diamino-3,3'-dimethyl-diphenylmethane, 4,4'-diamino-3,3'-diethyl-diphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone , 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl ketone and the like.
As the unsaturated imide resin, for example, a maleimide compound described in JP-A-2018-165340 can be used.

The thermosetting resin composition may include, in addition to the thermosetting resin, a curing agent, a curing accelerator, an inorganic filler, an organic filler, a coupling agent, a leveling agent, an antioxidant, and a flame retardant, if necessary. An embodiment containing at least one selected from a flame retardant aid, a thixotropic agent, a thickening agent, a thixotropic agent, a flexible material, a surfactant, a photopolymerization initiator and the like is preferable. In particular, with respect to the inorganic filler, in the present invention, the plate thickness accuracy can be improved without high filling, so that the content of the inorganic filler can be, for example, 10 to 60% by volume, and 20 to It may be 60% by volume or 30 to 60% by volume, and the upper limit value in the numerical range may be 57% by volume or 55% by volume. However, when it is necessary to highly fill the inorganic filler, in the present invention, it is not necessarily denied that the content of the inorganic filler exceeds 60% by volume, for example, the upper limit of the numerical range of the content. The value may be 70% by volume or 80% by volume.

In addition, for example, a modified silicone compound (modified silicone resin) described in International Publication No. WO 2012/099133, and, if necessary, other thermosetting resin, curing agent, curing accelerator, inorganic filler, heat Thermosetting containing at least one selected from the group consisting of a plastic resin, an elastomer, an organic filler, a flame retardant, an ultraviolet absorber, an antioxidant, a photopolymerization initiator, an optical brightener and an adhesion improver. Resin compositions and the like can also be used.
The modified silicone compound is preferably a silicone compound modified at both ends with amino groups. Specifically, (A) a siloxane diamine represented by the following general formula (1), and (B) at least two N-substituted maleimides in the molecular structure. A maleimide compound having a group, (C) a both-terminal amino-modified silicone compound obtained by reacting an amine compound having an acidic substituent represented by the following general formula (2), and the details are described in International Publication No. 2012/099133. On the street.

[In the formula (1), a plurality of R ¹ 's each independently represent an alkyl group, a phenyl group or a substituted phenyl group, and may be the same or different, and a plurality of R ² 's each independently represent an alkyl group, a phenyl group. Group or a substituted phenyl group, which may be the same or different from each other, R ³ and R ⁴ each independently represent an alkyl group, a phenyl group or a substituted phenyl group, and R ⁵ and R ⁶ each independently represent a divalent group. Indicates an organic group. n represents an integer of 2 to 50. ]

[In the formula (2), when a plurality of R ^7's are present, each independently represents a hydroxyl group, a carboxyl group or a sulfonic acid group, and when a plurality of R ^8's are present, each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms. Indicates a hydrocarbon group or a halogen atom. x is an integer of 1 to 5, y is an integer of 0 to 4, and x+y=5. ]

(Base material)
As the base material contained in the prepreg, a sheet-shaped reinforcing base material is used, and well-known materials used for various laminated plates for electrical insulating materials can be used. Examples of the material of the base material include natural fibers such as paper and cotton linters; inorganic fibers such as glass fibers and asbestos; organic fibers such as aramid, polyimide, polyvinyl alcohol, polyester, tetrafluoroethylene and acrylic; and mixtures thereof. To be Among these, glass fibers are preferable from the viewpoint of flame retardancy. Examples of the glass fiber base material include a woven fabric using E glass, C glass, D glass, S glass, or the like, or a glass woven fabric obtained by adhering short fibers with an organic binder; and a mixture of glass fiber and cellulose fiber. To be More preferably, it is a glass woven fabric using E glass.
These base materials have, for example, a woven cloth, a non-woven cloth, a robink, a chopped strand mat, a surfacing mat, or the like. The material and shape are selected depending on the intended use and performance of the molded product, and one kind may be used alone, or two or more kinds of material and shape may be combined if necessary.
The thickness of the base material may be, for example, 0.01 to 0.5 mm, preferably 0.015 to 0.2 mm, and 0.02 to 0 mm from the viewpoint of enabling moldability and high-density wiring. 0.15 mm is more preferable. From the viewpoint of heat resistance, moisture resistance, processability, etc., these base materials are preferably surface-treated with a silane coupling agent or the like, or mechanically opened.

(Prepreg)
After impregnating the base material with the thermosetting resin composition, a heat treatment is performed to obtain a prepreg in which the thermosetting resin composition is B-staged. From the viewpoint of handleability and tackiness of the prepreg, the prepreg is preferably subjected to a cooling step of cooling the prepreg. Cooling of the prepreg may be performed by natural cooling, or may be performed using a cooling device such as an air blower or a cooling roll. The temperature of the prepreg after cooling is usually 5 to 80°C, preferably 8 to 50°C, more preferably 10 to 30°C, and further preferably room temperature. The content of the thermosetting resin composition in terms of solid content in the prepreg is not particularly limited, but is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, and 50 to 80% by mass. % Is more preferable. The thickness of the prepreg is not particularly limited, but is preferably 20 to 150 μm, more preferably 60 to 120 μm, for example.

<Step (2-1) and Step (2-2)>
The step (2-1) is a step of laminating the metal foil 9 on the surface polished in the step (1) to form a metal-clad laminate. On the other hand, in the step (2-2), the metal foil 9 and the thermosetting resin film 10 or the thermosetting resin film 11 with the metal foil is attached to the surface 8 polished in the step (1) by the thermosetting resin. This is a step of forming the metal-clad laminate 12 by laminating the film 10 so as to be on the polished surface 8 side. The thermosetting resin film 11 with the metal foil is formed by disposing the thermosetting resin film 10 on the metal foil 9.
After step (1), either step (2-1) or step (2-2) may be selected, but a thermosetting resin layer having a depth obtained by polishing the cured product of the prepreg is provided. It is preferable to select the step (2-2) capable of By selecting the step (2-2), it is possible to return the thickness of the prepreg to the thickness before polishing, regardless of the amount of polishing in the step (1), and to adjust it to an arbitrary thickness. It is also possible.

The metal of the metal foil 9 (including the metal foil of the thermosetting resin film 11 with a metal foil) is not particularly limited as long as it is used for an electric insulating material, and from the viewpoint of conductivity, copper, Gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, or an alloy containing at least one of these metal elements is preferable, copper and aluminum are more preferable, and copper is further preferable. ..
The material of the thermosetting resin film used in the step (2-2) is preferably the same as the thermosetting resin composition contained in the prepreg used in the step (1).

[Metal-clad laminate]
The present invention also provides a metal-clad laminate obtained by the above manufacturing method.
Since the thickness of the cured product inside is substantially uniform, the metal-clad laminate of the present invention is also substantially uniform in thickness. Specifically, the difference between the maximum value and the minimum value of the thickness is 20 μm or less. It is obtained, and it excels in plate thickness accuracy. The difference between the maximum value and the minimum value of the thickness is 10 μm or less for the more excellent one and 5 μm or less for the more excellent one.
Here, the difference between the maximum value and the minimum value of the thickness and the difference between them are the values measured by the following method, and more specifically, the values measured by the method described in Examples.
<Difference between maximum and minimum values of thickness and calculation method of those differences>
A 550 mm square metal-clad laminate is cut into a size of 50 mm square and cut into 81 pieces in total. Samples at 17 points including the end and the center are selected, and the thickness at arbitrary 4 points is measured by a micrometer. From the data of 68 points in total, the maximum value, the minimum value, and the difference between them are calculated.

Further, the metal-clad laminate obtained by the production method of the present invention can have a thickness standard deviation (σ) of 10 μm or less, and is excellent in plate thickness accuracy. The more excellent standard deviation (σ) is 5 μm or less, and the more excellent one is 3 μm or less. Note that the standard deviation (σ) of the thickness is, for example, T ₁ , T ₂ ,..., T _n when the thicknesses at arbitrary n positions of the metal-clad laminate are measured, and When the average thickness of the laminated plate is T, the standard deviation at n points can be calculated from the following formula.

Moreover, as one aspect of the metal-clad laminate obtained by the production method of the present invention, (a) a cured product of a prepreg containing a thermosetting resin composition and a substrate, wherein at least one of the cured products A metal-clad laminate containing a cured product whose surface is polished, (b) a thermosetting resin composition layer containing no base material, and (c) a metal foil. In particular, the metal-clad laminate can be manufactured through the steps (1) and (2-2) in the manufacturing method.
The above-mentioned (a) is not particularly limited, but a mode in which both surfaces of the cured product are polished is preferable. The preferred embodiment of the polishing method is as described above.

[Printed wiring board]
The present invention also provides a printed wiring board containing the metal-clad laminate.
More specifically, the printed wiring board of the present invention can be manufactured by subjecting the metal foil of the metal-clad laminate to circuit processing. Circuit processing, for example, after forming a resist pattern on the metal foil surface, remove the unnecessary portion of the metal foil by etching, after peeling the resist pattern, to form a necessary through hole by a drill, after forming the resist pattern again, It can be performed by performing plating for electrical connection to the through hole and finally peeling off the resist pattern. The above-mentioned metal-clad laminate is further laminated on the surface of the printed wiring board thus obtained under the same conditions as described above, and the circuit is processed in the same manner as described above to form a multilayer printed wiring board. You can In this case, it is not always necessary to form a through hole, a via hole may be formed, and both can be formed. The required number of layers is provided in this way.
The printed wiring board of the present invention thus obtained is also excellent in plate thickness accuracy.

[Semiconductor package]
The semiconductor package of the present invention is obtained by mounting a semiconductor on the printed wiring board of the present invention. The semiconductor package of the present invention can be manufactured by mounting a semiconductor chip, a memory, etc. at a predetermined position on the printed wiring board of the present invention. Since the printed wiring board of the present invention is excellent in plate thickness accuracy, the semiconductor package of the present invention is (1) improved in yield at the time of mounting a semiconductor chip, and (2) on a build-up film or a rewiring layer. When L/S=2 μm/2 μm or less, the fine wiring formability is improved, (3) there is a tendency that the warp amount is reduced, and the warp amount is less likely to vary.

[Support for coreless substrate formation]
The present invention also provides a support for forming a coreless substrate, which comprises the metal-clad laminate of the present invention. On the support for coreless substrate formation (core substrate), an insulating resin composition layer having a circuit pattern is sequentially laminated to form a build-up layer, and then the support is separated to prepare a coreless substrate. It is possible. Since the coreless substrate forming support of the present invention has good plate thickness accuracy, it is possible to reduce the warp and surface waviness of the coreless substrate thus obtained, and thus it is suitable for improving the plate thickness accuracy of the coreless substrate.
The method for forming the buildup layer is not particularly limited, and a known method can be adopted. Explaining with reference to FIG. 3, for example, the buildup layer can be formed by the following method.
First, the prepreg 14 is arranged on the coreless substrate forming support (core substrate) 13 of the present invention. In addition, an adhesive layer may be arranged on the coreless substrate forming support (core substrate) 13 and then the prepreg 14 may be arranged. Then, the prepreg 14 is heated and cured to form an insulating layer. Next, after the via hole 15 is formed by a drill cutting method, a laser processing method using a YAG laser, a CO ₂ laser, or the like, surface roughening treatment and desmear treatment are performed if necessary. Subsequently, the circuit pattern 16 is formed by a subtractive method, a full additive method, a semi-additive method (SAP: Semi-Additive Process), a modified semi-additive method (m-SAP: modified Semi-Additive Process). The build-up layer 17 is formed by repeating the above process. A coreless substrate 18 is obtained by separating the formed buildup layer 17 from the coreless substrate forming support (core substrate) 13. The buildup layer 17 may be formed on one side of the support (core substrate) 13 or on both sides.

[Support for forming semiconductor redistribution layer]
The present invention also provides a support for forming a semiconductor redistribution layer, which comprises the metal-clad laminate of the present invention. The semiconductor redistribution layer is an insulating layer provided with copper wiring connected to the solder balls, and is usually an insulating layer provided between the semiconductor chip and the solder balls. In order to form the semiconductor redistribution layer, a semiconductor redistribution layer forming resin film is preferably used. However, since the semiconductor redistribution layer forming support of the present invention has good plate thickness accuracy, It effectively functions as a support for the rewiring layer forming resin film.

Next, the present invention will be described in more detail by the following examples, but these examples do not limit the present invention in any sense.

[Example 1]
First, a prepreg was produced according to the following procedure.
A modified silicone compound-containing solution was obtained by reacting 100 parts by mass of an amino-modified silicone compound at both ends, 222 parts by mass of bis(4-maleimidophenyl)methane and 8.5 parts by mass of p-aminophenol. Next, 16 parts by mass of the modified silicone compound-containing solution in terms of solid content, 16 parts by mass of naphthol aralkyl type epoxy resin, 69 parts by mass of fused silica [average particle diameter: 0.5 μm], 0.15 parts by mass of isocyanate mask imidazole. Were mixed to obtain a varnish having a resin content of 65% by mass. An E glass cloth having a thickness of 0.1 mm was impregnated and coated with the obtained varnish and dried by heating to obtain a prepreg (fused silica filling rate: 50% by volume).
Eight prepregs thus obtained were laminated, and low-pro type copper foils (thickness 12 μm, maximum height roughness (Rz) about 4.0 μm, manufactured by Mitsui Mining & Smelting Co., Ltd.) were laminated on both surfaces, and the pressure was 0.5 MPa. By heat-press molding at a temperature of 200 to 230° C. for about 2 hours, a laminate having copper foils on both sides (hereinafter referred to as copper-clad laminate a) was obtained.
Next, using the obtained copper clad laminate a, the copper foil was removed by etching to obtain a laminate. The surface roughness (Ra) of the surface of the laminate was measured under the following measurement conditions using a high-precision three-dimensional surface roughness measuring system (Veeco Instruments, Wyko NT9100). The result is shown in FIG.
Next, using a grinding device (automatic surface planer for 300 mm wafer, manufactured by DISCO, trade name "DAS8930") with a diamond bite on both front and back surfaces (that is, two surfaces having the largest area) of this laminate, Both sides were polished and flattened. The surface roughness (Ra) of the surface after polishing was measured under the following measurement conditions using a highly accurate three-dimensional surface shape roughness measuring system (Veeco Instruments, Wyko NT9100). The result is shown in FIG. It was confirmed that the surface waviness was smaller in FIG. 5 than in FIG.
Further, a thermosetting resin film (thickness: 10 μm) having the same components as the prepreg “GEA-705G” is arranged on both surfaces of the flattened laminate, and a copper foil (thickness: 12 μm) is arranged on the outer side thereof. A 550 mm square copper-clad laminate A capable of forming a circuit in the outermost layer was obtained by heating and pressing with a hot press. The cross section of the copper clad laminate A thus obtained was observed using a digital microscope (manufactured by KEYENCE, trade name "VHX-5000"). The image is shown in FIG.
<Measurement conditions of high precision 3D surface roughness measurement system>
Inner lens: 1x External lens: 50x Measurement range: 95μm (Y axis) x 95μm (X axis) at any position Measurement depth: 10μm
Measurement method: Vertical scanning interference method (VSI method)

The copper clad laminate obtained by the above method was evaluated according to the following evaluation methods. The results are shown in Table 1.

<Evaluation method>
(1. Maximum and minimum thicknesses of copper clad laminates and their differences)
The copper-clad laminate obtained in each example was cut into a size of 50 mm square with a wet diamond cutter and cut into 81 pieces in total. Samples at 17 locations including the edge and the center were selected, and the thickness at arbitrary 4 points was measured with a micrometer. From the data of 68 points in total, the maximum value and the minimum value of the plate thickness and their difference were calculated.

(2. Drill workability-broken life)
ULF coated drill “MCW Z699MWU” (φ0.15 mm (small diameter)×φ3.5 mm (large diameter), manufactured by Union Tool Co., Ltd., trade name) is used as a drill, and the rotation speed is 200,000 rpm and the feed speed is 2.0 m. /Min, chip load: 10.0 μm/rev. Evaluation was performed with 10,000 hits, and the number of hits until breakage occurred (broken life) was obtained, and this was used as an index of drill workability.

[Comparative Example 1]
In Example 1, the surface of the laminate in the copper-clad laminate a was not polished, and the copper-clad laminate a was used as it was, and each evaluation was performed according to the methods described above. The results are shown in Table 1.

[Reference Example 1]
A copper-clad laminate b was produced in the same manner as in the production of the copper-clad laminate a of Example 1 except that the filling rate of the inorganic filler in the prepreg was increased to 58% by volume. In order to confirm the drill workability when the filling rate of the inorganic filler was increased, the drill workability of the copper clad laminate b was evaluated according to the method described above. The results are shown in Table 1.

From Table 1, the copper clad laminate A obtained in Example 1 has extremely high plate thickness accuracy and good workability (drill workability). On the other hand, the copper clad laminate a of the comparative example resulted in inferior plate thickness accuracy as compared with the copper clad laminate A obtained in Example 1.
In the copper clad laminate b of Reference Example 1 in which the filling rate of the inorganic filler in the thermosetting resin composition was increased, the workability (drill workability) was lowered.

Since the metal-clad laminate obtained by the manufacturing method of the present invention has excellent thickness accuracy, it is useful for printed wiring boards and semiconductor packages for electronic devices.

1 Cured Product of Prepreg 2 Surface to be Polished 3 Central Part of Cured Product 4 Area Thinner than Central Area of Cured Product 5 Thinnest Area in Cured Product 6 Thermosetting Resin Composition 7 Base Material 8 Step (1 ) Polished surface 9) Metal foil 10 Thermosetting resin film 11 Thermosetting resin film with metal foil 12 Metal-clad laminate 13 Coreless substrate forming support (core substrate)
14 prepreg 15 via hole 16 circuit pattern 17 build-up layer 18 coreless substrate

Claims

(1) A step of polishing at least one surface of a cured product of a prepreg containing a thermosetting resin composition and a substrate,
(2-1) A step of laminating a metal foil on the surface polished in the step (1) to form a metal-clad laminate,
And a method for producing a metal-clad laminate.
(1) A step of polishing at least one surface of a cured product of a prepreg containing a thermosetting resin composition and a substrate,
(2-2) A metal foil and a thermosetting resin film or a thermosetting resin film with a metal foil is provided on the surface polished in the step (1), and the thermosetting resin film is on the polished surface side. Laminating to form a metal-clad laminate,
And a method for producing a metal-clad laminate.
The method for producing a metal-clad laminate according to claim 1 or 2, wherein, in the step (1), both surfaces of the cured product of the prepreg are polished.
The method for manufacturing a metal-clad laminate according to any one of claims 1 to 3, wherein the thickness of the cured product of the prepreg is made substantially uniform by polishing in the step (1).
5. The cured product of the prepreg is obtained by etching and removing a metal foil of a metal-clad laminate in which the surface of the cured product inside is not polished. Manufacturing method of metal-clad laminate.
The size of the surface of the cured product of the prepreg having the largest area is 200 mm to 1,300 mm in length×200 mm to 1,300 mm in width, and at least a part within a range of 70 mm from the end of the cured product of the prepreg. The method for producing a metal-clad laminate according to any one of claims 1 to 5, wherein the thickness is smaller than the thickness of the central portion of the cured product.
The method for producing a metal-clad laminate according to any one of claims 1 to 6, wherein in the step (1), the entire surface is polished until the thickness of the thinnest part of the cured product of the prepreg is adjusted.
In the step (1), (i) CMP (Chemical mechanical polishing) method, (ii) mechanical polishing such as fly-cutting, grinding, sandblasting, belt polishing, and scrubbing, (iii) persulfate, hydrogen peroxide-sulfuric acid The method for producing a metal-clad laminate according to any one of claims 1 to 7, wherein polishing is performed by a method selected from the group consisting of a mixture, chemical polishing using an inorganic acid, an organic acid and the like.
The method for producing a metal-clad laminate according to any one of claims 1 to 8, wherein the difference between the maximum value and the minimum value of the thickness of the obtained metal-clad laminate is 20 μm or less.
A metal-clad laminate obtained by the manufacturing method according to any one of claims 1 to 9.
(A) A cured product of a prepreg containing a thermosetting resin composition and a substrate, wherein at least one surface of the cured product is polished, and (b) a substrate-free thermal cure A metal-clad laminate containing a resin composition layer and (c) a metal foil.
A printed wiring board comprising the metal-clad laminate according to claim 10 or 11.
A semiconductor package in which a semiconductor element is mounted on the printed wiring board according to claim 12.
A support for forming a coreless substrate, which comprises the metal-clad laminate according to claim 10 or 11.
A support for forming a semiconductor redistribution layer, comprising the metal-clad laminate according to claim 10 or 11.