JP5988220B2 - Prepreg, metal-clad laminate, printed wiring board, multilayer printed wiring board - Google Patents

Description

  The present invention relates to a prepreg, a metal-clad laminate formed using the prepreg, a printed wiring board formed using the metal-clad laminate, and a multilayer printed wiring board.

  Conventionally, a prepreg is formed by impregnating a woven fabric base material with a resin composition containing a thermosetting resin and an inorganic filler and heating and drying until a semi-cured state is obtained (for example, Patent Document 1). 3). A metal-clad laminate can be produced by laminating a metal foil on the prepreg thus formed, and a printed wiring board can be produced by providing a conductor pattern on the metal-clad laminate. it can. Moreover, a multilayer printed wiring board can be manufactured by laminating a metal foil on the printed wiring board via a prepreg, removing an unnecessary portion of the metal foil, and providing a conductor pattern. Thereafter, a package (PKG) is manufactured by mounting and sealing a semiconductor element on the printed wiring board or the multilayer printed wiring board.

JP-A-8-288416 JP 2003-268136 A JP 2007-246668 A

  However, the conventional prepreg has a problem in that resin powder is likely to fall off. Further, when producing a metal-clad laminate using such a prepreg, there is also a problem that the thermosetting resin and the inorganic filler are separated, and appearance defects are likely to occur in the metal-clad laminate. Further, the insulation reliability and conduction reliability of a printed wiring board manufactured using such a metal-clad laminate may be lowered.

  The present invention has been made in view of the above points. A prepreg capable of reducing a powder fall and producing a laminate having a good appearance, a metal-clad laminate having a good appearance, and a printed wiring. An object of the present invention is to provide a board and a multilayer printed wiring board.

The prepreg according to the present invention is a prepreg formed by impregnating a woven fabric base material with a resin composition containing a thermosetting resin and an inorganic filler and drying by heating until a semi-cured state is obtained. the glass transition temperature by dynamic viscoelasticity measurement of the prepreg Ri 120 to 170 ° C. der, wherein the inorganic filler to the resin composition the total amount is one which is characterized that you have contained 65 to 85 wt% .

  In the prepreg, it is preferable that 50% by mass or more of the inorganic filler is spherical silica having an average particle size of 3 μm or less.

  In the prepreg, the thickness of the woven fabric base material is preferably 10 to 200 μm.

  The metal-clad laminate according to the present invention is formed by laminating a metal foil on the prepreg.

  The printed wiring board according to the present invention is formed by providing a conductive pattern on the metal-clad laminate.

  The multilayer printed wiring board according to the present invention is formed by laminating a metal foil on the printed wiring board through the prepreg, and removing a unnecessary portion of the metal foil to provide a conductor pattern. It is.

  According to the present invention, the powder transition of the prepreg can be reduced by the glass transition temperature measured by dynamic viscoelasticity measurement of the prepreg being 120 to 170 ° C. Moreover, when this prepreg is used, a laminated board (a metal-clad laminated board and a printed wiring board) with a favorable external appearance can be manufactured.

  Embodiments of the present invention will be described below.

  The prepreg according to the present invention is formed by impregnating a woven fabric substrate with a resin composition and heating and drying it until it is in a semi-cured state (B stage state).

  The above resin composition contains a thermosetting resin and an inorganic filler.

  Here, as a thermosetting resin, an epoxy resin, a phenol resin, cyanate resin, a melamine resin, an imide resin etc. can be used, for example. In particular, as the epoxy resin, for example, a polyfunctional epoxy resin, a bisphenol type epoxy resin, a novolac type epoxy resin, a biphenyl type epoxy resin, or the like can be used.

  Examples of the inorganic filler that can be used include silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, talc, and alumina.

  The inorganic filler is preferably contained in an amount of 60 to 85% by mass with respect to the total amount of the resin composition. As described above, when the content of the inorganic filler is 60% by mass or more, the coefficient of thermal expansion (CTE) of the prepreg and the laminate (metal-clad laminate and printed wiring board) is reduced. The elastic modulus can be increased, and the dimensional stability can be improved. Further, if the content of the inorganic filler is 85% by mass or less, the inorganic filler can be contained in the resin composition while suppressing an increase in viscosity, and the powdered prepreg is further reduced, and the appearance is further improved. A good laminate (metal-clad laminate and printed wiring board) can be obtained.

  Moreover, it is preferable that 50 mass% or more (upper limit is 100%) of spherical fillers having an average particle diameter of 3 μm or less (lower limit is 0.2 μm) with respect to the total amount of the inorganic filler, and the average particle diameter is 2 μm or less (lower limit is 0.00). 2 μm) of spherical silica is more preferable. As described above, since more than half of the inorganic filler is spherical silica having a small particle size, the aggregation of the inorganic filler can be suppressed and the separation between the thermosetting resin and the inorganic filler can be further suppressed. It is. The average particle diameter can be measured as a median diameter (50% diameter) using a laser diffraction particle size distribution measuring apparatus.

  Moreover, the resin composition may contain a curing agent and a curing accelerator.

  Here, as a hardening | curing agent, a phenol type hardening | curing agent, a dicyandiamide hardening | curing agent, etc. can be used, for example.

  Moreover, as a hardening accelerator, imidazoles, a phenol compound, amines, organic phosphines, etc. can be used, for example.

  And a resin composition can be prepared by blending the above-mentioned thermosetting resin, an inorganic filler, and a curing agent and a curing accelerator as required, and further by diluting this with a solvent, the resin composition Varnish can be prepared. As the solvent, for example, methyl ethyl ketone, toluene, styrene, methoxypropanol or the like can be used.

  Examples of the woven fabric substrate that can be used include those made of inorganic fibers such as glass cloth, glass paper, and glass mat, and those made of organic fibers such as aramid cloth.

  Moreover, it is preferable that the thickness of a woven fabric base material is 10-200 micrometers, and it is more preferable that it is 10-100 micrometers. Thus, when the thickness of the woven fabric substrate is 10 μm or more, the occurrence of warpage of the prepreg and the laminate (metal-clad laminate and printed wiring board) can be suppressed. Moreover, when the thickness of the woven fabric substrate is 200 μm or less, the package can be thinned.

  The prepreg according to the present invention can be produced by impregnating the above-mentioned resin composition into a woven fabric base material and heating and drying it until it is in a semi-cured state. The glass transition temperature of the prepreg measured by dynamic viscoelasticity is 120 to 170 ° C. The glass transition temperature of the prepreg is preferably 130 to 160 ° C, more preferably 140 to 160 ° C. In order to obtain a prepreg exhibiting such a glass transition temperature, for example, the resin content, the heating temperature, the heating time, and the like may be appropriately adjusted. Specifically, if the heating temperature is increased and the heating time is lengthened, the thermosetting resin is cured, and the glass transition temperature of the prepreg becomes higher than that before heating. As an example, if a prepreg having a glass transition temperature of 100 ° C. is additionally heated in a drying furnace at 100 to 180 ° C. for 1 to 6 minutes, a prepreg having a glass transition temperature of 120 to 170 ° C. can be obtained. . The glass transition temperature of the prepreg can be measured by diverting a DMA method (dynamic mechanical analysis method) that is usually used to measure the glass transition temperature of a metal-clad laminate.

  As mentioned above, when the glass transition temperature by the dynamic viscoelasticity measurement of a prepreg is 120-170 degreeC, the powder fall of the resin of a prepreg can be reduced. That is, when handling the prepreg or when cutting the prepreg to a predetermined size, powder falling off from the surface or cut surface of the prepreg is less likely to occur. And when manufacturing a metal-clad laminate as will be described later, when resin powder is mixed between them when laminating a prepreg and a metal foil, this portion becomes a dent, but as described above, the powder falls off. Since it becomes difficult to generate | occur | produce, the fall of the yield by mixing of resin powder can be suppressed. Furthermore, the glass transition temperature of the laminated board manufactured using the prepreg whose glass transition temperature is 120-170 degreeC becomes high. However, when the glass transition temperature of the prepreg is lower than 120 ° C., powder falling tends to occur as compared with a prepreg having a glass transition temperature of 120 ° C. or higher. Moreover, when manufacturing a laminated board using such a prepreg, the thermosetting resin and the inorganic filler are separated from each other as compared with the case where a prepreg having a glass transition temperature of 120 ° C. or higher is used. It becomes easy to do. In particular, when the thermosetting resin and the inorganic filler are separated, cracks are likely to occur in the laminate. Conversely, when the glass transition temperature of the prepreg is higher than 170 ° C., the prepreg is excessively cured, and the resin flow becomes worse when manufacturing a laminate, and there is a place where the resin is extremely small or no resin exists. As a result, poor appearance of the laminate is likely to occur.

  The metal-clad laminate according to the present invention is formed by laminating a metal foil on the prepreg. The prepreg is cured to become an insulating layer. In this case, a metal foil may be laminated and formed on one or both sides of one prepreg, or a plurality of prepregs may be laminated and a metal foil may be laminated on one or both sides. For example, a copper foil, an aluminum foil, a stainless steel foil, or the like can be used as the metal foil. The above lamination molding can be performed by heating and pressurizing using, for example, a multistage vacuum press, a double belt press, a linear pressure roll, a vacuum laminator, and the like. The molding conditions are, for example, a temperature of 140 to 350 ° C., a pressure of 0.5 to 6.0 MPa, and a time of 1 to 240 minutes. About the metal-clad laminated board manufactured as mentioned above, the glass transition temperature by a dynamic viscoelasticity measurement will be about 280-300 degreeC, and its external appearance is also favorable. Since the glass transition temperature of the prepreg according to the present invention is higher than that of the conventional one, when the lamination molding is performed in the same manner as in the past, the glass transition temperature of the obtained laminated plate becomes higher than that of the conventional one. Moreover, if the glass transition temperature of the conventional laminated board is good, since the molding time can be shortened because the glass transition temperature of the prepreg according to the present invention is high, the productivity of the laminated board can be improved.

  The printed wiring board according to the present invention is formed by providing a conductor pattern on the metal-clad laminate. The conductor pattern can be formed by, for example, a subtractive method or an additive method. The printed wiring board manufactured as described above also has a good appearance and a high glass transition temperature.

  The printed wiring board usually has two or less conductor patterns, but a printed wiring board (multilayer printed wiring board) having three or more conductor patterns can be produced as follows.

  That is, the multilayer printed wiring board according to the present invention can be formed by laminating a metal foil on the printed wiring board via the prepreg and removing a unnecessary portion of the metal foil to provide a conductor pattern. In this case, the printed wiring board serving as the core material for forming the multilayer printed wiring board is preferably formed using the prepreg according to the present invention, but may be formed using other prepregs. . Further, the metal foil may be laminated via the prepreg on one side or both sides of the printed wiring board. As the metal foil, the same ones as described above can be used. Lamination molding and molding conditions are the same as in the case of manufacturing a metal-clad laminate. The conductor pattern can be formed in the same manner as when a printed wiring board is manufactured. The multilayer printed wiring board produced as described above also has a good appearance and a high glass transition temperature. In particular, when a printed wiring board is manufactured using the prepreg according to the present invention and a multilayer printed wiring board is manufactured using this as a core material, the appearance of the multilayer printed wiring board is further improved. The number of conductor patterns is not particularly limited.

  Then, a package such as FBGA (Fine Pitch Ball Grid Array) can be manufactured by mounting and sealing a semiconductor element on the printed wiring board or the multilayer printed wiring board.

  Hereinafter, the present invention will be specifically described by way of examples.

Example 1
As the thermosetting resin, “EPPN502H” manufactured by Nippon Kayaku Co., Ltd., which is a polyfunctional epoxy resin, was used.

  As the inorganic filler, “SO-C6” (average particle size 2 μm) manufactured by Admatechs Co., Ltd., which is spherical silica, was used.

  As the curing agent, “MEH7600” manufactured by Meiwa Kasei Co., Ltd., which is a phenolic curing agent, was used.

  Further, 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd.) was used as a curing accelerator.

  As a woven fabric base material, “1037 cloth” (thickness 30 μm) manufactured by Asahi Kasei Corporation, which is a glass cloth, was used.

  And the varnish of the resin composition was prepared by mix | blending said thermosetting resin, an inorganic filler, a hardening | curing agent, and a hardening accelerator with the compounding quantity shown in Table 1, and also diluting with a solvent (methyl ethyl ketone).

  Next, the woven fabric base material is impregnated with the above resin composition, and the prepreg is heated and dried (primary heating) in a drying furnace at 100 to 200 ° C. for 5 to 15 minutes until it becomes a semi-cured state. Manufactured. Further, this prepreg was additionally dried by heating (secondary heating) at 120 ° C. for 2 minutes.

  Next, two prepregs as described above are stacked, and copper foil ("3EC-VLP" manufactured by Mitsui Mining & Smelting Co., Ltd., thickness 18 μm) is laminated and molded on both sides as a metal foil, thereby forming copper as a metal-clad laminate. A tension laminate (CCL) was produced. The above lamination molding was performed by heating and pressurizing using a multistage vacuum press. The molding conditions are a temperature of 220 ° C., a pressure of 6.0 MPa, and a time of 160 minutes.

(Example 2)
A prepreg and a metal-clad laminate were produced in the same manner as in Example 1 except that the secondary heating was performed at 150 ° C. for 2 minutes.

(Example 3)
A prepreg and a metal-clad laminate were produced in the same manner as in Example 1 except that the secondary heating was performed at 170 ° C. for 2 minutes.

Example 4
A prepreg and a metal-clad laminate were produced in the same manner as in Example 2 except that the blending amounts of the thermosetting resin, the inorganic filler, the curing agent, and the curing accelerator were changed.

(Example 5)
A prepreg and a metal-clad laminate were produced in the same manner as in Example 2 except that the blending amounts of the thermosetting resin, the inorganic filler, the curing agent, and the curing accelerator were changed.

(Example 6)
A prepreg was produced in the same manner as in Example 1.

  Next, a metal-clad laminate was produced in the same manner as in Example 1 except that only one prepreg was used.

  Next, a printed wiring board was manufactured by providing a conductor pattern only on one side of the metal-clad laminate by the subtractive method.

  Thereafter, a copper foil (“3EC-VLP” manufactured by Mitsui Kinzoku Mining Co., Ltd., thickness 18 μm) is laminated and formed on the conductor pattern forming surface of the printed wiring board as a metal foil via a prepreg similar to the above. A multilayer printed wiring board was manufactured. The above lamination molding was performed by heating and pressurizing using a multistage vacuum press. The molding conditions are a temperature of 220 ° C., a pressure of 6.0 MPa, and a time of 160 minutes.

(Comparative Example 1)
A prepreg and a metal-clad laminate were produced in the same manner as in Example 1 except that secondary heating was not performed.

(Comparative Example 2)
A prepreg and a metal-clad laminate were produced in the same manner as in Example 1 except that the secondary heating was performed at 180 ° C. for 2 minutes.

(Glass transition temperature of prepreg)
The glass transition temperature of the prepreg measured by dynamic viscoelasticity was measured by a DMA method (dynamic mechanical analysis method) according to JIS C 6481. Specifically, a prepreg was first cut into a size of 50 mm × 5 mm to prepare a sample. Next, the sample was heated using a dynamic viscoelasticity measuring apparatus (“DMS6100” manufactured by SII Nano Technology Co., Ltd.) at 5 ° C./min, and the peak position of tan δ was defined as the glass transition temperature.

(Prepreg powder fall)
Fifty prepregs each having a size of 340 mm × 500 mm were stacked and dropped onto a steel table from a height of 20 mm, and the state of resin powdering was observed. The quality was determined as follows based on the amount of powder dropped.

  “◯”: The powder is almost free from falling off.

  “△”: Slightly powdered, but no problem in practical use.

  "X": A thing with much powder fall-off.

(Appearance of metal-clad laminate)
The metal foil of the metal-clad laminate was removed by etching, and the appearance was judged as follows by observing the removed surface.

  “◯”: A streak pattern caused by separation between the thermosetting resin and the inorganic filler is not observed.

  “Δ”: The above streak pattern is partially seen, but there is no particular problem in practical use.

  “× (A)”: The above-mentioned streak pattern can be seen as a whole.

  “× (B)”: A place where a small amount of resin or a place where no resin exists is observed.

(Glass transition temperature of metal-clad laminate)
The glass transition temperature of the metal-clad laminate measured by dynamic viscoelasticity measurement was measured according to JIS C 6481 by the DMA method (dynamic mechanical analysis method). Specifically, first, the metal foil of the metal-clad laminate was removed by etching, and this was cut into a size of 50 mm × 5 mm to prepare a sample. Next, the sample was heated using a dynamic viscoelasticity measuring apparatus (“DMS6100” manufactured by SII Nano Technology Co., Ltd.) at 5 ° C./min, and the peak position of tan δ was defined as the glass transition temperature.

  As is apparent from Table 1, the prepregs of Examples 1 to 5 having a glass transition temperature of 120 to 170 ° C. by dynamic viscoelasticity measurement have reduced powder falling. In addition, when such a prepreg is used, a metal-clad laminate having a good appearance can be produced.

  On the other hand, in the prepreg of Comparative Example 1, since the glass transition temperature by dynamic viscoelasticity measurement is less than 120 ° C., powder falling occurs. Moreover, the external appearance of the metal-clad laminate produced using such a prepreg is poor.

  Moreover, in the comparative example 2, although the powder fall of a prepreg is reduced, the external appearance of a metal-clad laminated board is unsatisfactory.

Claims (6)

A prepreg formed by impregnating a woven fabric base material with a resin composition containing a thermosetting resin and an inorganic filler, and drying by heating until a semi-cured state,
Ri glass transition temperature of 120 to 170 ° C. der by dynamic viscoelasticity measurement of the prepreg,
Prepregs wherein the inorganic filler to the resin composition the total amount characterized that you have contained 65 to 85 wt%. The prepreg according to claim 1, wherein 50% by mass or more of the inorganic filler is spherical silica having an average particle diameter of 3 μm or less. The prepreg according to claim 1 or 2 , wherein the woven fabric base has a thickness of 10 to 200 µm. A metal-clad laminate, wherein the prepreg according to any one of claims 1 to 3 is laminated with a metal foil. A printed wiring board, wherein the metal-clad laminate according to claim 4 is provided with a conductor pattern. A metal foil is laminated on a printed wiring board through the prepreg according to any one of claims 1 to 3 , and an unnecessary portion of the metal foil is removed to provide a conductor pattern. Multi-layer printed wiring board.