JP4976719B2 - Insulation sheet, insulation sheet with metal foil and multilayer printed wiring board - Google Patents

Description

  The present invention relates to an insulating sheet, an insulating sheet with a metal foil, and a multilayer printed wiring board.

  Along with demands for higher functionality of electronic devices, electronic parts have been increasingly integrated with high density and further mounted with high density. For this reason, multilayer printed wiring boards and the like used in these electronic devices are required to be smaller and higher in density.

In order to increase the density of multilayer printed wiring boards and the like, there is a limit in the multilayer technology by forming through holes formed by conventional drilling, and recently, a build-up method has been widely adopted.
The multilayer printed wiring board obtained by the build-up method is designed to increase the density of circuit wiring by sequentially laminating and forming an insulating layer mainly composed of a resin and a conductor layer and performing interlayer connection. .

In particular, among the multilayer printed wiring boards, the semiconductor chip mounting substrate (interposer) has a high density of circuit wiring by the build-up method.
The semiconductor chip mounting substrate employs a structure in which FC (Flip / Chip) using fine bumps for connection to the semiconductor chip is mounted in order to further reduce the size and speed.
In recent years, in FC, in order to facilitate the formation of fine bumps and to suppress the use of lead that is harmful to the environment, liquid-solid phase diffusion connection using high-temperature solder (pb95, etc.) has been replaced by solid stud bumps. Phase-solid diffusion connections are often employed. For this reason, the semiconductor chip mounting substrate is required to have a mounting property of the semiconductor chip under high temperature and high pressure and mounting reliability after mounting the semiconductor chip.
However, a conventional semiconductor chip mounting substrate made of a build-up wiring board has poor mounting properties because the bump connection pad sinks at the time of solid-phase diffusion connection using gold stud bumps, causing connection failure. It was enough.
Further, the conventional semiconductor chip mounting substrate has insufficient mounting reliability due to an insulation failure caused by a change in the thickness of the insulating layer.
Such a problem has also occurred in other fields of multilayer printed wiring boards.

JP 2001-189536 A

An object of the present invention is to provide an insulating sheet excellent in mountability of a semiconductor chip and an insulating sheet with a metal foil when used for a multilayer printed wiring board.
Another object of the present invention is to provide a multilayer printed wiring board excellent in mountability of a semiconductor chip.

Such an object is achieved by the present invention described in the following (1) to (7).
(1) An insulating sheet that is used to form a multilayer wiring printed board and is used by being superimposed on one or both sides of an inner layer circuit,
The insulating sheet is composed of a resin composition containing an epoxy resin and an inorganic filler containing silica, and heated at 200 ° C. for 90 minutes, and then measured by heating at a tensile mode of 5 ° C./minute. When the storage elastic modulus at 250 ° C. of the insulating sheet is A [MPa] and the storage elastic modulus at 200 ° C. is B [MPa], a relationship of (A−B) / 50 ≧ −60 [MPa / ° C.] An insulating sheet characterized by satisfying
(2) The storage modulus at 250 ° C. of the insulating sheet measured by heating at 200 ° C. for 90 minutes and then by heating at a tensile mode of 5 ° C./min is 100 [MPa] or more (1) The insulation sheet as described in 2.
(3) The insulating sheet according to (1) or (2), wherein the epoxy resin includes two or more different types of epoxy resins.
(4) The insulating sheet according to any one of (1) to (3), wherein the epoxy resin includes two or more epoxy resins having different weight average molecular weights.
(5) The insulating sheet according to any one of (1) to (4), wherein the amount of compressive deformation when the semiconductor chip is mounted is 10 μm or less.
(6) An insulating sheet with a metal foil, wherein the insulating sheet according to any one of (1) to (5) above and a metal foil are laminated.
(7) A multilayer printed wiring board using the insulating sheet according to any one of (1) to (6).

ADVANTAGE OF THE INVENTION According to this invention, when used for a multilayer printed wiring board, the insulating sheet excellent in the mountability of a semiconductor chip and an insulating sheet with metal foil can be provided.
Moreover, according to the present invention, it is possible to provide a multilayer printed wiring board that is excellent in mountability of a semiconductor chip.
Further, when a cyanate resin is used as the curable resin and combined with an inorganic filler having a specific particle size, the mountability can be particularly improved.

Hereinafter, the insulating sheet, the insulating sheet with metal foil, and the multilayer printed wiring board of the present invention will be described.
The insulating sheet of the present invention is an insulating sheet composed of a resin composition containing a curable resin and an inorganic filler, and the insulating sheet has an elastic modulus at 250 ° C. of 100 [MPa] or more. It is a feature.
The insulating sheet of the present invention is an insulating sheet composed of a resin composition containing a curable resin and an inorganic filler, and the insulating sheet has an elastic modulus at 250 ° C. of A [MPa], 200 (A−B) / 50 ≧ −60 [MPa / ° C.] when the elastic modulus at C is B [MPa].
Moreover, the insulating sheet with a metal foil of the present invention is characterized in that the insulating sheet and the metal foil are laminated.
The multilayer printed wiring board of the present invention is characterized by using the above insulating sheet.

Hereinafter, the insulating sheet of the present invention will be described.
The insulating sheet of the present invention is an insulating sheet composed of a resin composition containing a curable resin and an inorganic filler, and the insulating sheet has an elastic modulus at 250 ° C. of 100 [MPa] or more. Thereby, the mountability of the semiconductor chip of a multilayer printed wiring board (especially semiconductor chip mounting base | substrate) can be improved using the insulating sheet of this invention. That is, since the insulating sheet has a high elastic modulus even at a high temperature of 250 ° C., the sinking of the pad that occurs when the gold stud bump is connected can be improved. Therefore, the mountability of the semiconductor chip can be improved without causing an insulation failure.
Furthermore, since the insulating sheet has a high elastic modulus even at a high temperature at which a semiconductor chip is mounted, the ultrasonic wave used at the time of bump connection by the gold stud bump is effectively transmitted to the bump connection portion. It is also possible to improve the strength. Therefore, the mounting reliability after mounting the semiconductor chip can also be improved.
The elastic modulus (storage elastic modulus) of the insulating sheet can be measured by, for example, a dynamic viscoelasticity measuring device (DMA). As a measurement condition, for example, a rate of temperature increase of 5 ° C./min in the tensile mode can be mentioned.

  Conventionally, bumps are connected by solder. However, a method using gold stud bumps has been performed in response to recent demands for lead-free soldering due to bump miniaturization and environmental problems. The insulating sheet of the present invention makes it possible to provide a multilayer printed wiring board (especially a substrate for mounting a semiconductor chip) having sufficient mountability of a semiconductor chip and mounting reliability after mounting the semiconductor chip even on a gold stud bump. Is.

  Further, the elastic modulus at 250 ° C. of the insulating sheet is preferably 100 [MPa] or more, particularly preferably 150 [MPa] to 2.0 [GPa]. If the elastic modulus is less than the lower limit, the effect of improving the mountability may be reduced, and even if the upper limit is exceeded, there is no problem in mountability, but depending on the structure of the semiconductor chip mounting substrate, the bump In some cases, the stress on the connection portion increases and the mounting reliability decreases.

  The elastic modulus at 260 ° C. of the insulating sheet is not particularly limited, but is preferably 100 [MPa] or more, and particularly preferably 150 [MPa] to 2.0 [GPa]. When the elastic modulus at 260 ° C. is within the above range, it is possible to particularly improve the solder mounting property when mounting a semiconductor chip particularly at a high temperature.

In addition, the mounting temperature of the semiconductor chip is not particularly limited and is not necessarily 250 ° C. For example, the semiconductor chip may be mounted at 200 ° C. lower than 250 ° C. Therefore, in practice, the elastic modulus at the temperature at which the semiconductor chip of the insulating sheet is mounted is preferably 100 [MPa] or more, and particularly preferably 150 [MPa] to 2.0 [GPa]. . When the elastic modulus is within the above range, the mounting property and mounting reliability of the semiconductor chip can be particularly improved.
The elastic modulus is estimated from the fact that the pressure applied per bump when the semiconductor chip is mounted is about 100 [MPa]. That is, if the elastic modulus of the insulating sheet is equal to or higher than the pressure applied to one bump, it can withstand compressive deformation.
The elastic modulus of the insulating sheet is preferably as high as possible in terms of mountability. However, when the elastic modulus at 250 ° C. is high and the thermal expansion coefficient described later is large, the stress on the bumps becomes large and the mounting reliability may be lowered. That is, the reason why the mounting reliability is lowered is that the stress strain applied to the bumps may increase when the difference between the thermal expansion coefficient of the insulating sheet having a high elastic modulus and the thermal expansion coefficient of the semiconductor chip is large. is there.
The amount of compressive deformation of the insulating sheet when mounted on a semiconductor chip is not particularly limited, but is preferably 10 μm or less, particularly preferably 5 μm or less, and most preferably 2 μm or less. When the amount of compressive deformation is within the above range, the mountability is particularly excellent.

Examples of the curable resin include novolak type phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, phenol resin such as resol type phenol resin, and bisphenol type epoxy such as bisphenol A epoxy resin and bisphenol F epoxy resin. Resin, novolac epoxy resin, cresol novolac epoxy resin, etc., novolac epoxy resin, biphenyl type epoxy resin, etc., novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, bisphenol F type cyanate resin, etc. Examples include cyanate resins such as bisphenol type cyanate resins. Among these, cyanate resins (particularly novolak type cyanate resins) are preferable. Thereby, the elasticity modulus of an insulating sheet can be improved easily. Cyanate resins (particularly novolak-type cyanate resins) have a small decrease in elastic modulus even at a glass transition temperature or higher, and can maintain a high elastic modulus at high temperatures.
The cyanate group of the cyanate resin is trimerized by heating to form a triazine ring having a high crosslinking density. Therefore, when a cyanate resin is used, a high elastic modulus can be achieved particularly in a high temperature region. It can improve especially that the elasticity modulus in the temperature more than a glass transition temperature falls.

Examples of the cyanate resin include those obtained by reacting a cyanogen halide compound with phenols. The prepolymerized cyanate resin is also included in the cyanate resin of the present invention.
The weight average molecular weight of the cyanate resin (particularly the novolak type cyanate resin) is not particularly limited, but is preferably 500 to 4,500. If the weight average molecular weight is less than the lower limit, the crosslinking density is small and the effect of improving the mounting reliability of the semiconductor chip may be reduced, and if the upper limit is exceeded, the reaction may not be completed.
The weight average molecular weight can be measured in terms of polystyrene using, for example, gel permeation chromatography.

Although content of the said curable resin is not specifically limited, 20 to 70 weight% of the whole said resin composition is preferable, and 30 to 60 weight% is especially preferable. If the content is less than the lower limit value, the effect of improving the mountability of the semiconductor chip may be reduced. If the content exceeds the upper limit value, the crosslink density is increased and the free volume is increased, so that the moisture resistance may be reduced. .
Moreover, especially when using cyanate resin as curable resin, the content is although it does not specifically limit, 10 to 60 weight% of the whole resin composition is preferable, and 25 to 40 weight% is especially preferable.

Although the said curable resin is not specifically limited, It is preferable that 2 or more of the same or different kind of curable resin is included. Thereby, compatibility of the mounting property of a semiconductor chip, the moisture resistance of an insulating sheet, etc. can be aimed at.
Examples of the two or more curable resins of the same kind include a combination of a novolac-type cyanate resin and a bisphenol-type cyanate resin, and a combination of a novolac-type epoxy resin and a bisphenol-type epoxy resin.
Examples of the two or more different curable resins include a combination of a cyanate resin and an epoxy resin, a cyanate resin and a novolac resin, an epoxy resin and a phenol resin, a cyanate resin, and an epoxy resin and a phenol resin. . Among these, a combination of cyanate resin, epoxy resin and phenol resin is preferable. This is because the phenol resin is effective in promoting the crosslinking reaction of the cyanate resin and can act as a curing agent for the epoxy resin after acting as a catalyst for the cyanate resin. Therefore, the hardened | cured material of an epoxy resin and a phenol resin can reduce the free volume which arises by the crosslinking reaction of cyanate resin more, and can improve moisture resistance by it.

The curable resin is not particularly limited, but preferably includes two or more curable resins having different weight average molecular weights. Thereby, the moldability of an insulating sheet can be improved. Also, it is possible to achieve both circuit embedding and flow control during press molding.
Specifically, for example, it is preferable to include a mixture of a first epoxy resin and a second epoxy resin having a weight average molecular weight higher than that of the first epoxy resin. Thereby, it is possible to achieve both circuit embedding and flow control during press molding.

  Examples of the first epoxy resin include phenol novolac type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, arylalkylene type epoxy resins, and the like. Among these, aryl alkylene type epoxy resins are preferable. Thereby, a flame retardance and moisture absorption solder heat resistance can be improved. Here, the aryl alkylene type epoxy resin refers to an epoxy resin having one or more aryl alkylene groups in a repeating unit. For example, a xylylene type epoxy resin, a biphenyl dimethylene type epoxy resin, etc. are mentioned. Among these, a biphenyl dimethylene type epoxy resin is preferable.

  The weight average molecular weight of the first epoxy resin is not particularly limited, but is preferably 4,000 or less, particularly preferably 500 to 3,500, and most preferably 800 to 3,000. When the weight average molecular weight is less than the lower limit value, the insulating sheet may be tacked. When the weight average molecular weight exceeds the upper limit value, solder heat resistance and circuit embedding property may be reduced.

  Although content of the said 1st epoxy resin is not specifically limited, 3 to 30 weight% of the whole resin composition is preferable, and 5 to 20 weight% is especially preferable. When the content is within the above range, the moisture-absorbing solder heat resistance can be particularly improved.

  Examples of the second epoxy resin include phenol novolac type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, arylalkylene type epoxy resins and the like. Among these, bisphenol type epoxy resins are preferable. Thereby, adhesiveness with copper foil etc. can be improved.

  The weight average molecular weight of the second epoxy resin is not particularly limited, but is preferably 5,000 or more, particularly preferably 5,500 to 100,000, and most preferably 8,000 to 80,000. If the weight average molecular weight is less than the lower limit, the effect of improving the formability of the insulating sheet may be reduced, and if it exceeds the upper limit, the solubility of the epoxy resin may be reduced, thereby improving workability. May decrease.

  Although content of the said 2nd epoxy resin is not specifically limited, 3 to 30 weight% of the whole resin composition is preferable, and 5 to 20 weight% is especially preferable. When the content is within the above range, particularly the formability of the insulating sheet and the inner layer circuit adhesion during the production of the multilayer printed wiring board can be improved.

  Examples of the inorganic filler include silicates such as talc, calcined clay, unfired clay, mica and glass, oxides such as titanium oxide, alumina, silica and fused silica, calcium carbonate, magnesium carbonate, hydrotalcite and the like. Carbonates, hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, sulfates or sulfites such as barium sulfate, calcium sulfate, calcium sulfite, zinc borate, barium metaborate, aluminum borate, boron Examples thereof include borates such as calcium oxide and sodium borate, and nitrides such as aluminum nitride, boron nitride, and silicon nitride. Among these, silica, particularly spherical silica is preferable, and spherical fused silica is most preferable. Thereby, the filling property of the inorganic filler can be improved, and thereby the insulating sheet can be particularly reduced in expansion. Moreover, the melt viscosity of the resin composition can be kept low by using spherical silica.

  The average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 to 5 μm, and particularly preferably 0.2 to 2 μm. When the particle size of the inorganic filler is less than the lower limit value, the viscosity of the varnish becomes high, and the workability when producing the insulating sheet may be lowered. When the upper limit is exceeded, phenomena such as sedimentation of the inorganic filler may occur in the varnish.

  Although content of the said inorganic filler is not specifically limited, 20 to 70 weight% of the whole resin composition is preferable, and 35 to 60 weight% is especially preferable. When the content is less than the lower limit, the effect of increasing the elastic modulus and the low thermal expansion may be reduced. When the content exceeds the upper limit, the moldability may be reduced due to the decrease in fluidity.

  Although it does not specifically limit in the said resin composition, It is preferable to contain a coupling agent further. The coupling agent improves the heat resistance, particularly the solder heat resistance after moisture absorption, by uniformly fixing the resin and the filler to the substrate by improving the wettability of the interface between the resin and the inorganic filler. be able to.

  As the coupling agent, any commonly used one can be used, and among these, one selected from an epoxy silane coupling agent, a titanate coupling agent, an aminosilane coupling agent, and a silicone oil type coupling agent. It is preferable to use the above coupling agent. Thereby, the wettability with the interface of the inorganic filler is improved, and the heat resistance can be further improved.

  The content of the coupling agent is preferably 0.05 to 3 parts by weight, particularly preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the inorganic filler. If the content is less than the lower limit value, the inorganic filler cannot be sufficiently coated and the effect of improving heat resistance may be reduced, and if the content exceeds the upper limit value, the bending strength of the insulating sheet may be reduced.

Moreover, in order to accelerate | stimulate hardening of the said resin composition, you may use a well-known curing catalyst.
Examples of the curing catalyst include organic metal salts represented by zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate and the like, copper acetylacetonate, aluminum acetylacetonate, cobalt acetylacetonate and the like. Metal complexes, tertiary amines such as triethylamine, tributylamine, quinoline and isoquinoline, quaternary ammonium salts such as tetraethylammonium chloride and tetrabutylammonium bromide, aromatics represented by phenol, nonylphenol, catechol, pyrogal, and dihydroxynaphthalene Hydroxy compound, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, bis (2-ethyl-4-methyl-imidazole), 2-phenyl-4-methyl-5 Hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1 -Cyanoethyl-2-ethyl-4-methylimidazole, 1-aminoethyl-2-methylimidazole, 1- (cyanoethylaminoethyl) -2-methylimidazole, 1-cyanoethyl-2-phenyl-4,5-bis (cyano There are imidazoles represented by ethoxymethylimidazole) or triazine addition type imidazole. These may be used alone or in combination of two or more.

  Further, the resin composition includes an antifoaming agent for preventing voids, a liquid or powder flame retardant for improving flame retardancy, a phenoxy resin, a polyamide resin for improving toughness and adhesion, A thermoplastic resin such as a polyester resin, a polyimide resin, a polyurethane resin, a polystyrene resin, an acrylic resin, or a silicone resin can also be added.

The insulating sheet of the present invention is an insulating sheet composed of a resin composition containing a curable resin and an inorganic filler, and the insulating sheet has an elastic modulus at 250 ° C. of A [MPa], 200 The relationship of (A−B) / 50 ≧ −60 [MPa / ° C.] is satisfied when the elastic modulus at C is B [MPa]. As a result, it is possible to provide a multilayer printed wiring board (particularly, a semiconductor chip mounting substrate) that is highly adaptable to changes in the mounting temperature of the semiconductor chip. That is, it is possible to obtain a multilayer printed wiring board that is less affected by changes in the mounting temperature of the semiconductor chip.
The relationship (A−B) / 50 between the elastic modulus A [MPa] at 250 ° C. and the elastic modulus B [MPa] at 200 ° C. of the insulating sheet satisfies −50 [MPa / ° C.] or more. Is preferable, and it is particularly preferable to satisfy −30 to 0 [MPa / ° C.]. Within the above range, the mountability of the semiconductor chip can be improved.
The elastic modulus at 250 ° C. of the insulating sheet satisfying the above relationship is not particularly limited, but is preferably 100 [MPa] or more. Thereby, it is excellent in the mounting property of the semiconductor chip especially at high temperature.

Next, the insulating sheet with metal foil of the present invention will be described.
In the sheet with metal foil of the present invention, the insulating sheet and metal foil are laminated.
That is, the insulating sheet is formed on at least one side of the metal foil.
As a method for producing the insulating sheet with metal foil, for example, a method of heating and pressurizing a previously prepared insulating sheet and metal foil, a method of applying and drying a varnish of a resin composition constituting the insulating sheet on the metal foil, etc. Is mentioned. Among these, the method of applying and drying the varnish of the resin composition constituting the insulating sheet on the metal foil is preferable. Thereby, an insulating sheet with metal foil can be manufactured efficiently.

  When using a method of applying a resin composition varnish constituting an insulating sheet to a metal foil and drying, the resin composition is made of alcohols, ethers, acetals, ketones, esters, alcohol esters, ketone alcohols. , Varnish for producing insulating sheet is prepared by dissolving in organic solvents such as ether alcohols, ketone ethers, ketone esters and ester ethers. Next, the varnish can be obtained by coating on a metal foil and drying.

Examples of the metal constituting the metal foil include copper or a copper alloy, iron or an iron alloy, aluminum or an aluminum alloy, and the like.
Moreover, although the thickness of the insulating layer of the said insulating sheet with metal foil is not specifically limited, 10-100 micrometers is preferable and especially 20-80 micrometers is preferable. When the thickness is within the above range, the effect of preventing the insulating layer from cracking can be improved.

Next, the multilayer printed wiring board of the present invention will be described.
The multilayer printed wiring board of the present invention uses the insulating sheet.
For example, it can be obtained by overlapping the insulating sheet on one or both sides of the inner layer circuit and further forming a conductor layer. Further, it is obtained by superposing the above-mentioned insulating sheet with metal foil on one side or both sides of the inner layer circuit and heating and pressing.
Although the said heating temperature is not specifically limited, 140-240 degreeC is preferable. Although the said pressurization pressure is not specifically limited, 10-40 kg / cm < ² > is preferable.
Examples of the inner layer circuit board include a circuit formed on both sides of a copper clad laminate and blackened.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited by this.

Example 1
1. Preparation of Resin Varnish As curable resin, 20% by weight of novolak cyanate resin (PT-30, Lonza Corporation, weight average molecular weight 1,300) and novolak cyanate resin (PT-60, Lonza Corporation, weight) 10 wt% of average molecular weight 2,300), 10 wt% of bisphenol A type and F type mixed epoxy resin (Epicoat 4275, manufactured by JER, weight average molecular weight 57,000), biphenyldimethylene type epoxy resin (NC-3000P, Nippon Kayaku Co., Ltd., epoxy equivalent 275) 19.5% by weight and 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.) 0.5% by weight as a curing agent dissolved in methyl ethyl ketone , Dispersed.
Further, spherical fused silica (SO-25H, Admatex Co., Ltd.) surface-treated by adding 0.5 parts by weight of an epoxy silane coupling agent (A-187, manufactured by Nihon Unicar Co., Ltd.) to 100 parts by weight of the inorganic filler. 40% by weight (made by a company) was blended as an inorganic filler and stirred for 10 minutes using a high-speed stirrer. C. A 65% resin varnish was obtained.

2. Production of Insulating Sheet with Copper Foil The above resin varnish was applied to the anchor surface of a copper foil having a thickness of 18 μm with a comma coater so that the resin thickness after drying was 60 μm to obtain an insulating sheet with copper foil.

3. Production of Resin Plate The insulating sheet surfaces of the above-mentioned insulating sheet with copper foil are overlapped, heated and pressed at a pressure of 2 MPa and a temperature of 200 ° C. for 90 minutes, the copper foil on both sides is removed by etching, and a resin plate having a thickness of 120 μm Was made. The elastic modulus at 250 ° C. of the insulating sheet was 1,500 MPa.

4). Production of Build-up Wiring Board The above-mentioned insulating sheet with copper foil was placed on a printed wiring board on which a predetermined inner layer circuit was formed, and was heated and pressed at a pressure of 3.5 MPa and a temperature of 200 ° C. for 90 minutes. The inner and outer layers were connected by a window method using a CO ₂ laser to produce a four-layer build-up wiring board having a predetermined conductor pattern.

(Example 2)
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
As curable resin, 20% by weight of novolak type cyanate resin (PT-30), 5% by weight of novolak type cyanate resin (PT-60), 15% by weight of bisphenol A type and F type mixed epoxy resin (Epicoat 4275) , Biphenyldimethylene type epoxy resin (NC-3000P) 9.5% by weight, 2-phenyl-4,5-dihydroxymethylimidazole 0.5% by weight as a curing agent, and surface-treated spherical particles as an inorganic filler Fused silica (SO-25H) 50% by weight was used. The insulating sheet had an elastic modulus at 250 ° C. of 1,600 MPa.

Example 3
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
As the curable resin, 20% by weight of novolac-type cyanate resin (PT-30), 20% by weight of bisphenol A-type and F-type mixed epoxy resin (Epicoat 4275), biphenyldimethylene-type epoxy resin (NC-3000P) 19. 5 wt% was used, 0.5 wt% 2-phenyl-4,5-dihydroxymethylimidazole was used as a curing agent, and 40 wt% surface-treated spherical fused silica (SO-25H) was used as an inorganic filler. Note that the elastic modulus at 250 ° C. of the insulating sheet was 300 MPa.

Example 4
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
As the curable resin, 20% by weight of novolak type cyanate resin (PT-30 described above), 40% by weight of novolak type cyanate resin (PT-60 described above), bisphenol A type and F type mixed epoxy resin (Epicoat 4275). ) 5 wt% and biphenyl dimethylene type epoxy resin (NC-3000P) 4.8 wt%, 2-phenyl-4,5-dihydroxymethylimidazole 0.2 wt% as a curing agent, inorganic filler As a surface treatment, 30% by weight of spherical fused silica (SO-25H) subjected to surface treatment was used. The insulating sheet had an elastic modulus at 250 ° C. of 1,000 MPa.

(Example 5)
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
As the curable resin, 20% by weight of novolak type cyanate resin (PT-30), 15% by weight of novolak type cyanate resin (PT-60), and 15% by weight of bisphenol A type and F type mixed epoxy resin (Epicoat 4275) , 19.5% by weight of biphenyl dimethylene type epoxy resin (NC-3000P), 0.5% by weight of 2-phenyl-4,5-dihydroxymethylimidazole as a curing agent, and surface-treated spherical particles as an inorganic filler 30% by weight of fused silica (SO-25H) was used. Note that the elastic modulus at 250 ° C. of the insulating sheet was 700 MPa.

(Example 6)
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
As a curable resin, 10% by weight of novolak-type cyanate resin (PT-30), 10% by weight of bisphenol A type and F type mixed epoxy resin (Epicoat 4275), and biphenyldimethylene type epoxy resin (NC-3000) 9 0.5 wt%, 2-phenyl-4,5-dihydroxymethylimidazole 0.5 wt% as a curing agent, and 70 wt% of surface-treated spherical fused silica (SO-25H) as an inorganic filler. . Note that the elastic modulus at 250 ° C. of the insulating sheet was 2,100 MPa.

(Example 7)
Example 1 was performed except that the following inorganic fillers were used.
As the inorganic filler, 40% by weight of crushed silica (SQ-PL2 manufactured by Izumi Tech Co., Ltd.) was used. The insulating sheet had an elastic modulus at 250 ° C. of 1,700 MPa.

(Example 8)
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
As a curable resin, 25% by weight of a polyfunctional epoxy resin (Epicoat E1031S) and 4.5% by weight of a biphenyldimethylene type epoxy resin (NC-3000) are used, and 2-phenyl-4,5-dihydroxy is used as a curing agent. The amount of methylimidazole 0.5% by weight and spherical fused silica (SO-25H) as an inorganic filler was 70% by weight. The insulating sheet had an elastic modulus at 250 ° C. of 1,000 MPa.

(Comparative Example 1)
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
As the curable resin, 40% by weight of bisphenol A type and F type epoxy resin (Epicoat 4275) and 19.5% by weight of biphenyldimethylene type epoxy resin (NC-3000P) are used, and 2-phenyl- as the curing agent. 4,5-dihydroxymethylimidazole 0.5% by weight and 40% by weight of spherical fused silica (SO-25H) surface-treated as an inorganic filler were used. The elastic modulus at 250 ° C. of the insulating sheet was not measurable.

The following evaluation was performed by the following method about the insulating sheet and multilayer printed wiring board obtained by each Example and the comparative example. The obtained results are shown in Table 1.
1. Thermal elastic modulus Thermal elastic modulus is a 120 μm thick resin plate, heated at 5 ° C./min using DMA (manufactured by TA Instruments), storage elastic modulus at 250 ° C. and storage elastic modulus at 200 ° C. Was measured respectively.

2. Thermal expansion coefficient The thermal expansion coefficient was a resin plate having a thickness of 120 μm, heated at 10 ° C./min using TMA (manufactured by TA Instruments), and measured for a thermal expansion coefficient of 50 to 150 ° C.

3. Mountability Mountability was evaluated by the amount of pad depression when tool bonding was performed. Specifically, a ball bonder (4524A manufactured by K & S) is used for a multilayer printed wiring board having an insulating layer thickness of 60 μm and a pad specification of 60 μm in diameter, tool diameter: 50 μmφ, load: 120 g, temperature: 250 ° C., and ultrasonic waves Tool bonding was performed for 1 second while applying.

4). TC (Temperature Cycle) Test Ten daisy chain type semiconductor packages for evaluation, which connect a semiconductor element and a multilayer printed wiring board through 300 bumps, were produced.
After confirming the continuity of the semiconductor package for evaluation described above, a temperature cycle (TC) test was performed in which one cycle was 10 minutes at −50 ° C. and 10 minutes at 125 ° C. The number of defective disconnections after 1,000 cycles of the TC test was evaluated.

5. PCT
The number of defects after the above semiconductor package for evaluation was treated at 121 ° C./100% (2 atm) for 196 hours was evaluated.

6). Insulation reliability test Four-layer printed wiring boards for insulation reliability test, having a comb pattern with a conductor spacing of 50 μm on the inner and outer layers, were measured with an automatic super insulation resistance meter (manufactured by ADVANTEST). Thereafter, a DC voltage of 50 V was applied in an atmosphere of 85 ° C./85%, and the insulation resistance after 1000 hours was measured. The applied voltage at the time of measurement was 100 V for 1 minute, and the insulation resistance (Ω) was evaluated.

As is apparent from Table 1, in Examples 1 to 8, the amount of sinking of the pad was small and the mountability was improved.
In addition, Examples 1 to 8 had no defective number in the temperature cycle test and were excellent in heat resistance.
In addition, Examples 1 to 8 had no defective number in the PCT test and were excellent in moisture resistance.
In Examples 2, 6 and 8, the coefficient of thermal expansion was particularly low.

Claims (7)

An insulating sheet used to form a multilayer wiring printed board and used by being superimposed on one or both sides of an inner layer circuit,
The insulating sheet is composed of a resin composition containing an epoxy resin and an inorganic filler containing silica, and heated at 200 ° C. for 90 minutes, and then measured by heating at a tensile mode of 5 ° C./minute. When the storage elastic modulus at 250 ° C. of the insulating sheet is A [MPa] and the storage elastic modulus at 200 ° C. is B [MPa], a relationship of (A−B) / 50 ≧ −60 [MPa / ° C.] An insulating sheet characterized by satisfying The insulation according to claim 1, wherein the insulating sheet has a storage elastic modulus at 250 ° C. of 100 [MPa] or more measured by heating at 200 ° C. for 90 minutes and then increasing the temperature at a tensile mode of 5 ° C./minute. Sheet.   The insulating sheet according to claim 1, wherein the epoxy resin includes two or more different types of epoxy resins.   The insulating sheet according to any one of claims 1 to 3, wherein the epoxy resin includes two or more epoxy resins having different weight average molecular weights.   The insulating sheet according to any one of claims 1 to 4, wherein the insulating sheet has a compressive deformation amount of 10 µm or less when a semiconductor chip is mounted.   An insulating sheet with a metal foil, wherein the insulating sheet according to any one of claims 1 to 5 and a metal foil are laminated.   A multilayer printed wiring board comprising the insulating sheet according to any one of claims 1 to 6.