JP2009094217A - Semiconductor, printed circuit board for semiconductor device, and copper clad laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relieve internal stress when a printed circuit board for a semiconductor or the semiconductor device is manufactured, to reduce curvature variation of an interposer caused before or after a reflow stage, to stably manufacture the semiconductor device, and to improve the yield in a secondary mounting stage. <P>SOLUTION: The semiconductor device manufactured using the printed circuit board for the semiconductor device having a plurality of layers of conductor circuits is characterized in that a size variation amount after the reflow stage of the printed circuit board for the semiconductor device is ≤0.04%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor device, a printed wiring board for a semiconductor device, and a copper clad laminate.

  With recent demands for higher functionality and lighter, thinner and smaller electronic devices, electronic components have been increasingly integrated and densely packaged. Semiconductor devices used in these electronic devices have been reduced in size and increased in number of pins, and mounting substrates on which electronic components including the semiconductor device are mounted have also been reduced in size. Furthermore, in order to improve the storage property in an electronic device, a rigid flex board that can be bent by laminating and integrating a rigid board and a flexible board has been used as a mounting board.

  With the miniaturization of semiconductor devices as well, the conventional semiconductor device using a lead frame has a limit on miniaturization, and recently, a printed wiring board for semiconductor devices (hereinafter referred to as an interposer). As a chip mounted on top, new area mounting type semiconductor devices such as BGA (Ball Grid Array) and CSP (Chip Scale Package) have been proposed. However, the trend of miniaturization, weight reduction, and high functionality of electronic devices is not limited, and in addition to the trend of thinning as seen in mobile phones, the thinning of semiconductor devices has rapidly progressed. ing.

  As the semiconductor device becomes thinner in this way, the thickness of the semiconductor chip and the sealing material, which conventionally has been responsible for most of the rigidity of the semiconductor device, becomes extremely thin, and warping of the semiconductor device is likely to occur. Further, since the proportion of the interposer as a constituent member of the substrate becomes large, the physical properties and behavior of the interposer have a great influence on the warp of the semiconductor device.

  However, with the progress of lead-free soldering from the viewpoint of protecting the global environment, the maximum temperature in the reflow process that is experienced when solder balls are mounted on a semiconductor device and when mounted on a mother board has become very high. Since the melting point of lead-free solder, which is commonly used, is around 210 degrees, the maximum temperature during the reflow process is at a level exceeding 240 degrees. For this reason, extremely high heat resistance has been demanded from the past assuming that the reflow process is repeated. As a means for improving the heat resistance of an organic material, a method of increasing the glass transition temperature (Tg) of the material is known. In a substrate material used for an interposer, the Tg exceeds 180 degrees. ing. For this reason, the strain accumulated inside the substrate material for the interposer is not sufficiently released by the thermal history received during the interposer manufacturing process and the semiconductor device assembly process, and the strain is released only after the reflow process. Therefore, there is a problem that the warpage of the semiconductor device greatly fluctuates.

  Therefore, the substrate material for the interposer needs to have a characteristic of high elasticity during heat in order to improve the mountability during the reflow process. In addition, if the strain due to thermal expansion is large, the stress of the substrate becomes high and the characteristic that the thermal expansion coefficient is low is also required. On the other hand, even a thin substrate needs to have high rigidity at room temperature. That is, the substrate material must have high heat resistance, that is, high glass transition temperature (Tg). For this reason, a substrate material satisfying such characteristics has been developed.

On the other hand, when the semiconductor chip mounting surface is molded and sealed with an epoxy resin composition or the like, if the interposer is a thin substrate having a thickness of 500 μm or less, a large warp occurs due to solidification shrinkage of the epoxy resin composition or the like. In order to reduce the amount of warpage, a conventional technique is known in which the semiconductor element mounting surface is sealed with a resin sealing layer having a low thermal expansion coefficient (see, for example, Patent Document 1).
JP 2000-216299 A

  Therefore, in the present invention, it is possible to reduce the warpage of the semiconductor device by paying attention to the dimensional change amount before and after the reflow process of the substrate material for the interposer, and managing the distortion amount accumulated in the interposer as a numerical value. I found out. Since it is heated at a temperature higher than the maximum temperature achieved during the curing process of the copper clad laminate, the internal stress when the interposer or the semiconductor device using the copper clad laminate is relaxed and occurs before and after the reflow process. The warpage variation of the interposer can be reduced, the semiconductor device can be stably manufactured, and the yield in the secondary mounting process can be improved.

That is, the present invention is a method of manufacturing a semiconductor device having a structure in which a semiconductor chip is mounted on an interposer and the semiconductor is protected by a sealing resin, and the dimensional change before and after the reflow process of the interposer is 0.04% or less. Thus, warping of the semiconductor device is suppressed. In particular, it corresponds to a semiconductor device having a very thin structure.
In addition, by mounting the semiconductor chip so that the circuit surface faces the interposer, even in a flip chip semiconductor device in which the protection of the semiconductor chip by the sealing material is not necessarily required, the warpage of the semiconductor device is suppressed by the same method. Can do.

Such an object is achieved by the present invention described in the following [1] to [6].
[1] In a semiconductor device manufactured using a printed wiring board for a semiconductor device having a plurality of layers of conductor circuits, the dimensional change before and after the reflow process of the printed wiring board for a semiconductor device is 0.04% or less. A featured semiconductor device.
[2] The semiconductor device according to [1], wherein an average linear expansion coefficient at a glass transition temperature (Tg) or lower of the printed wiring board for a semiconductor device is 3 ppm / ° C. or higher and 12 ppm / ° C. or lower.
[3] The semiconductor device according to [1] or [2], wherein the printed circuit board for a semiconductor device has an elastic modulus at room temperature of 1 GPa to 30 GPa.
[4] Any one of [1] to [3], wherein the printed wiring board for a semiconductor device is manufactured using a copper-clad laminate including at least a cyanate resin, an epoxy resin, and a curing agent. The semiconductor device according to item.
[5] A printed wiring board for a semiconductor device, which is used in any one of items [1] to [4].
[6] A copper-clad laminate, which is used in any one of items [1] to [4].

  In the semiconductor device of the present invention, heating is performed at a temperature higher than the highest temperature during the curing process of the copper-clad laminate, so that the internal stress when the interposer or semiconductor device using the copper-clad laminate is reduced is reduced. Therefore, the warp fluctuation of the interposer occurring before and after the reflow process can be reduced, the semiconductor device can be stably manufactured, and the yield in the secondary mounting process can be improved.

The semiconductor device of the present invention is formed by mounting a semiconductor chip on an interposer, electrically connecting the semiconductor chip and the interposer, and then covering the semiconductor chip with a sealing material to protect the semiconductor chip. However, warping of the semiconductor device is suppressed by using the interposer whose dimensional change before and after the reflow process is 0.04% or less.
For mounting the semiconductor chip on the interposer, both face-up and face-down methods can be used. In the case of the face-down method, an underfill resin or an organic resin can be filled between the semiconductor chip and the interposer. For example, the entire semiconductor chip is not necessarily protected by the sealing material.

The thickness of the semiconductor device is not specifically defined, but the effect is significant when the total thickness of the interposer, the semiconductor chip, and the sealing resin is 700 μm or less. This is conspicuous when the ratio of the thickness of the poser is between 75% and 125%.
Further, there is a tendency that the effect is more remarkable as the thickness of the semiconductor chip is thinner, and the effect is large when the chip thickness is 250 μm or less, and is remarkable when the thickness is 200 μm or less.

Next, a method for reducing the interposer dimensional change before and after the reflow process to 0.04% or less will be described. A copper clad laminate as a base material of an interposer is a composite material manufactured through many processes, and includes strains generated during the manufacturing process. For this reason, at the time of copper foil etching, the distortion is released during the heating process, and a dimensional change occurs. There is no major problem when the strain is gradually released during the semiconductor device assembly process, but the recent copper-clad laminate for interposers tends to have a high Tg to cope with the lead-free solder process. There is almost no distortion until the reflow process is performed. In order to avoid this, it is necessary to release the strain by heating the interposer to a temperature equal to or higher than Tg before the semiconductor device assembly process.
However, when the interposer is heated, the interposer warpage increases due to the deterioration and deterioration of the surface treatment formed on the conductor circuit, the deterioration of the solder resist formed on the surface of the interposer, and the asymmetry of the front and back circuit design. There is a concern of affecting the reliability after being incorporated in a semiconductor device. Moreover, Tg in this invention is calculated | required from the inflection point of the dimensional change behavior obtained by TMA (TA Instruments 2940 made from TA Instruments).

  In order to avoid the above-mentioned concerns, the present inventors heated and removed the strain up to Tg of the copper-clad laminate at the time of production of the copper-clad laminate, so that the dimensional variation was extremely large during the reflow process of semiconductor device production. I found that I could get fewer interposers. The above heat distortion effect can also be obtained by heating in a free state so as not to apply external force to the substrate, but there are significant limitations such as heating in an oxygen-free state to avoid copper oxidation. . For this reason, heat distortion can be performed while suppressing the oxidation of copper by heating to Tg or more in a state where the upper and lower sides are sandwiched between the upper and lower sides in a vacuum press for pressure-molding the copper-clad laminate. Under the present circumstances, since it is restrained with the flat metal plate during heating, the curvature increase of the copper clad laminated board by strain release can be suppressed.

In addition, when an excessive load is applied during the above-mentioned heat distortion, local strain may be applied to the copper clad laminate, and attention is required. Specifically, it is necessary to perform heat distortion by limiting the load to 9 kg / cm ² or less. Even if the heating time is longer than necessary, the effect does not increase. Therefore, 60 minutes or less is sufficient after the copper-clad laminate reaches a temperature of Tg or higher. Further, even if it is too short, sufficient distortion cannot be obtained, so it is necessary to maintain a temperature of Tg or more for at least 5 minutes.

Furthermore, even if sufficient distortion is performed as described above, the linear expansion coefficient (CT) of the interposer
When E) is large, the amount of warpage caused by the difference from the CTE of the semiconductor chip is large, and the warp reduction effect due to distortion removal is not sufficiently exhibited. Specifically, when it is 12 ppm / ° C. or less, the warp reduction effect due to strain removal is superior to the warp due to the difference in CTE. In addition, the smaller the CTE of the interposer, the more the warp can be reduced. However, the CTE is reduced by increasing the proportion of glass cloth and inorganic filler contained in the copper-clad laminate, so that the CTE is excessively low. Causes deterioration of machinability during the interposer processing step, and the CTE of the semiconductor chip is 3 ppm / ° C., so it is necessary to set it to 3 ppm / ° C. or more.

  In addition to the above, if the modulus of elasticity of the interposer is too low, the ratio of the rigidity of the semiconductor device to the rigidity of the semiconductor chip and the sealing material increases, and the contribution of the physical properties of the interposer to the warpage of the semiconductor device is low. Thus, the above-mentioned distortion eliminating effect is not sufficiently exhibited. For this reason, the elastic modulus of the interposer is required to be 1 GPa or more. In addition, even if the elastic modulus is increased more than necessary, it is necessary to control the elastic modulus below a level at which machining is possible in order to greatly affect the machinability at the time of manufacturing the interposer. Specifically, it is desirable that it is 40 GPa or less.

  The copper-clad laminate is obtained by impregnating a fiber base material such as glass cloth with a resin composition containing a thermosetting resin and drying at a predetermined temperature to obtain a prepreg. Using this prepreg, both sides of the prepreg 12 are obtained. A copper-clad laminate is produced by stacking a metal foil or film on the substrate and then heating and pressing (FIG. 2 (b)). The resin composition is used as a resin varnish for impregnating the fiber base material.

Examples of thermosetting resins used for copper-clad laminates are modified with novolak-type phenolic resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, unmodified resole phenolic resin, tung oil, linseed oil, walnut oil, etc. Phenolic resin such as resol-type phenolic resin such as oil-modified resol phenolic resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol P type Epoxy resin, bisphenol type epoxy resin such as bisphenol Z type epoxy resin, novolac type epoxy resin such as phenol novolac type epoxy resin, cresol novolac epoxy resin , Biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, aryl alkylene type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type epoxy resin, adamantane type epoxy resin, Epoxy resin such as fluorene type epoxy resin, resin having triazine ring such as urea (urea) resin, melamine resin, unsaturated polyester resin, bismaleimide resin, polyurethane resin, diallyl phthalate resin, silicone resin, resin having benzoxazine ring And cyanate resin.
One of these may be used alone, or two or more having different average molecular weights may be used in combination, or one or two or more and those prepolymers may be used in combination.
Of these, cyanate resins (including prepolymers of cyanate resins) are particularly preferable. Thereby, the thermal expansion coefficient of a copper clad laminated board can be made small, and also it can be set as the copper clad laminated board excellent in electrical characteristics (low dielectric constant, low dielectric loss tangent), machine mechanical strength, etc.

The cyanate resin can be obtained by, for example, reacting a halogenated cyanide compound with a phenol and prepolymerizing it by a method such as heating as necessary. Specific examples include bisphenol type cyanate resins such as novolak type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, and tetramethylbisphenol F type cyanate resin. Among these, novolac type cyanate resin is preferable. Thereby, the heat resistance improvement by an increase in a crosslinking density and flame retardances, such as a resin composition, can be improved. This is because the novolac-type cyanate resin forms a triazine ring after the curing reaction. Furthermore, it is considered that novolak-type cyanate resin has a high benzene ring ratio due to its structure and is easily carbonized. Furthermore, excellent rigidity can be imparted even when the copper-clad laminate has a thickness of 500 μm or less. In particular, since the rigidity during heating is excellent, the reliability when mounting the semiconductor chip 31 of FIG.

  As said novolak-type cyanate resin, what is shown, for example by Formula (I) can be used.

The average repeating unit n of the novolak cyanate resin represented by the above formula (I) is not particularly limited, but is preferably 1 to 10, and particularly preferably 2 to 7. When the average repeating unit n is less than the lower limit, the novolak cyanate resin has low heat resistance, and the low-mer may be desorbed and volatilized during heating. Moreover, when average repeating unit n exceeds the said upper limit, melt viscosity will become high too much and the moldability of the prepreg 12 may fall.
The average molecular weight of the cyanate resin is not particularly limited, but an average molecular weight of 500 to 4,500 is preferable, and 600 to 3,000 is particularly preferable. When the average molecular weight is less than the above lower limit, tackiness may occur when the prepreg 12 is produced, and when the prepregs 12 come into contact with each other, they may adhere to each other or transfer of the resin may occur. In addition, when the average molecular weight exceeds the above actual value, the reaction becomes too fast, and when the interposer 11 is used, a molding defect occurs,
Interlaminar peel strength may decrease. The average molecular weight of the cyanate resin or the like can be measured by, for example, GPC (gel permeation chromatography, standard substance: converted to polystyrene).

  Moreover, although it does not specifically limit, the said cyanate resin can also be used individually by 1 type, 2 or more types which have different average molecular weights are used together, or 1 type, or 2 or more types, and those prepolymers are used together. You can also do it.

  Although content of the said thermosetting resin is not specifically limited, 5 to 50 weight% of the whole said resin composition is preferable, and 20 to 40 weight% is especially preferable. If the content is less than the lower limit, it may be difficult to form a copper clad laminate, and if the content exceeds the upper limit, the strength of the copper clad laminate may be reduced.

  Moreover, it is preferable that the said resin composition contains an inorganic filler. Thereby, even if a copper-clad laminate described later is made thin (thickness of 500 μm or less), it can be excellent in strength. Furthermore, it is possible to improve the low thermal expansion of the copper-clad laminate.

  Examples of the inorganic filler include silicates such as talc, fired 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, nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride, and titanates such as strontium titanate and barium titanate. As the inorganic filler, one of these can be used alone, or two or more can be used in combination. Among these, silica is particularly preferable, and fused silica (particularly spherical fused silica) is preferable in terms of excellent low thermal expansion. The shape is crushed and spherical, but in order to reduce the melt viscosity of the resin composition in order to ensure the impregnation of the fiber substrate, a method of use that suits the purpose, such as using spherical silica, is adopted. .

The average particle diameter of the inorganic filler is not particularly limited, but is preferably 0.01 to 5.0 μm, particularly preferably 0.1 to 2.0 μm. If the particle size of the inorganic filler is less than the lower limit, the viscosity of the varnish becomes high, which may affect the workability during the production of the copper-clad laminate.
If the upper limit is exceeded, phenomena such as sedimentation of the inorganic filler may occur in the varnish. This average particle diameter can be measured, for example, by a particle size distribution meter (manufactured by HORIBA, LA-500).
The inorganic filler is not particularly limited, and an inorganic filler having a monodispersed average particle diameter can be used, and an inorganic filler having a polydispersed average particle diameter can be used. Furthermore, one type or two or more types of inorganic fillers having an average particle size of monodispersed and / or polydispersed may be used in combination.
Furthermore, spherical silica (especially spherical fused silica) having an average particle size of 5.0 μm or less is preferable, and spherical fused silica having an average particle size of 0.01 to 2.0 μm is particularly preferable. Thereby, the filling property of an inorganic filler can be improved.
Although content of the said inorganic filler is not specifically limited, 20 to 80 weight% of the whole resin composition is preferable, and 30 to 70 weight% is especially preferable. When the content is within the above range, particularly low thermal expansion and low water absorption can be achieved.

When a cyanate resin (especially a novolac-type cyanate resin) is used as the thermosetting resin, it is preferable to use an epoxy resin (substantially free of halogen atoms). Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, and bisphenol Z type epoxy resin. Bisphenol type epoxy resin, phenol novolak type epoxy resin, cresol novolac epoxy resin and other novolak type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin and other aryl alkylene type epoxy resin, naphthalene type epoxy resin, Anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type epoxy resin, Adama Tan type epoxy resins, and fluorene type epoxy resins. As an epoxy resin, one of these can be used alone, or two or more having different average molecular weights can be used in combination, or one or two or more and those prepolymers can be used in combination. You can also. Among these epoxy resins, aryl alkylene type epoxy resins are particularly preferable. Thereby, moisture absorption solder heat resistance and a flame retardance can be improved.

  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. A biphenyl dimethylene type | mold epoxy resin can be shown, for example by Formula (II).

  The average repeating unit n of the biphenyl dimethylene type epoxy resin represented by the above formula (II) is not particularly limited, but is preferably 1 to 10, and particularly preferably 2 to 5. When the average repeating unit n is less than the lower limit, the biphenyldimethylene type epoxy resin is easily crystallized, and its solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. On the other hand, if the average repeating unit n exceeds the above upper limit, the fluidity of the resin is lowered, which may cause molding defects.

  Although content of the said epoxy resin is not specifically limited, 1 to 55 weight% of the whole resin composition is preferable, and 2 to 40 weight% is especially preferable. If the content is less than the lower limit, the reactivity of the cyanate resin may be reduced, or the moisture resistance of the product obtained may be reduced. If the content exceeds the upper limit, the heat resistance may be reduced.

  The average molecular weight of the epoxy resin is not particularly limited, but an average molecular weight of 500 to 20,000 is preferable, and 800 to 15,000 is particularly preferable. When the average molecular weight is less than the above lower limit value, tackiness may occur in the prepreg 12, and when the above upper limit value is exceeded, the impregnation property into the glass cloth is lowered when the prepreg 12 is produced, and a uniform product cannot be obtained. There is. The average molecular weight of the epoxy resin can be measured by, for example, GPC.

When using cyanate resin (especially novolak-type cyanate resin) as said thermosetting resin, it is preferable to use a phenol resin. Examples of the phenol resin include novolac-type phenol resins, resol-type phenol resins, and arylalkylene-type phenol resins. One of these can be used alone as a phenol resin, or two or more having different average molecular weights can be used in combination, or one or two or more can be used in combination with a prepolymer thereof. You can also. Among these, arylalkylene type phenol resins are particularly preferable. Thereby, moisture absorption solder heat resistance can be improved further.
Examples of the aryl alkylene type phenol resin include a xylylene type phenol resin and a biphenyl dimethylene type phenol resin. A biphenyl dimethylene type phenol resin can be shown, for example by Formula (III).

  Although the repeating unit n of the biphenyl dimethylene type phenol resin represented by the above formula (III) is not particularly limited, 1 to 12 is preferable, and 2 to 8 is particularly preferable. If the average repeating unit n is less than the lower limit, the heat resistance may be lowered. Moreover, when the said upper limit is exceeded, compatibility with other resin will fall and workability | operativity may fall.

  The combination of the above-mentioned cyanate resin (particularly novolak-type cyanate resin) and arylalkylene-type phenol resin can control the crosslinking density and easily control the reactivity.

Although content of the said phenol resin is not specifically limited, 1 to 55 weight% of the whole resin composition is preferable, and 5 to 40 weight% is especially preferable. When the content is less than the above lower limit, the heat resistance may be lowered, and when the content exceeds the upper limit, the characteristics of low thermal expansion may be impaired.
The average molecular weight of the phenol resin is not particularly limited, but an average molecular weight of 400 to 18,000 is preferable, and 500 to 15,000 is particularly preferable. When the average molecular weight is less than the above lower limit value, tackiness may occur in the prepreg 12, and when the above upper limit value is exceeded, the impregnation property into the glass cloth is lowered when the prepreg 12 is produced, and a uniform product cannot be obtained. There is. The average molecular weight of the phenol resin can be measured by GPC, for example.

Further, the cyanate resin (especially novolac-type cyanate resin), the phenol resin (arylalkylene-type phenolic resin, particularly biphenyldimethylene-type phenolic resin), and the epoxy resin (arylalkylene-type epoxy resin, especially biphenyldimethylene-type epoxy resin). In particular, when the interposer 11 is manufactured using the combination, it is possible to obtain particularly excellent dimensional stability.

  Although the said resin composition is not specifically limited, It is preferable to use a coupling agent. The coupling agent uniformly fixes the thermosetting resin and the inorganic filler to the glass cloth by improving the wettability at the interface between the thermosetting resin and the inorganic filler. In particular, solder heat resistance after moisture absorption can be improved.

Any coupling agent can be used as long as it is usually used. Specifically, an epoxy silane coupling agent, a cationic silane coupling agent, an amino silane coupling agent, a titanate coupling agent, and a silicone oil type coupling. It is preferable to use one or more coupling agents selected from among the agents. Thereby, the wettability with the interface of an inorganic filler can be made high, and thereby heat resistance can be improved more.
The addition amount of the coupling agent is not particularly limited because it depends on the specific surface area of the inorganic filler, but is preferably 0.05 to 3 parts by weight, particularly 0.1 to 2 parts per 100 parts by weight of the inorganic filler. Part by weight is preferred. If the content is less than the above lower limit value, the inorganic filler cannot be sufficiently coated, so the effect of improving the heat resistance may be reduced. If the content exceeds the above upper limit value, the reaction will be affected, and the bending strength will be reduced. There is a case.

  A curing accelerator may be used in the resin composition as necessary. A well-known thing can be used as said hardening accelerator. For example, organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), trisacetylacetonate cobalt (III), triethylamine, tributylamine, diazabicyclo [2,2 , 2] tertiary amines such as octane, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole Imidazoles such as 2-phenyl-4,5-dihydroxyimidazole, phenolic compounds such as phenol, bisphenol A and nonylphenol, organic acids such as acetic acid, benzoic acid, salicylic acid and paratoluenesulfonic acid, or mixtures thereof. It is. As the curing accelerator, one kind including these derivatives can be used alone, or two or more kinds including these derivatives can be used in combination.

  Although content of the said hardening accelerator is not specifically limited, 0.05 to 5 weight% of the whole said resin composition is preferable, and 0.2 to 2 weight% is especially preferable. If the content is less than the above lower limit, the effect of promoting curing may not appear, and if the content exceeds the upper limit, the storability of the prepreg 12 may be reduced.

  In the above resin composition, phenoxy resin, polyimide resin, polyamideimide resin, polyphenylene oxide resin, polyethersulfone resin, polyester resin, polyethylene resin, polystyrene resin and other thermoplastic resins, styrene-butadiene copolymer, styrene-isoprene copolymer. Polystyrene thermoplastic elastomers such as polymers, polyolefin thermoplastic elastomers, thermoplastic elastomers such as polyamide elastomers and polyester elastomers, and diene elastomers such as polybutadiene, epoxy-modified polybutadiene, acrylic-modified polybutadiene, and methacryl-modified polybutadiene are used in combination. You may do it.

  In addition, additives other than the above components such as pigments, dyes, antifoaming agents, leveling agents, ultraviolet absorbers, foaming agents, antioxidants, flame retardants, and ion scavengers are added to the resin composition as necessary. May be added.

  The resin composition is impregnated into a glass cloth as a fiber base material to produce a prepreg 12 (FIG. 2A). Thereby, the prepreg 12 suitable for manufacturing a semiconductor device excellent in various characteristics such as dielectric characteristics, mechanical and electrical connection reliability under high temperature and high humidity can be obtained. As such a prepreg 12, commercially available products include cyanate products manufactured by Sumitomo Bakelite Co., Ltd. and bismaleimide triazine products manufactured by Mitsubishi Gas Chemical.

  In the present embodiment, a glass cloth (glass fiber base material) is used, but is not limited to this. For example, polyamide resin fibers, aromatic polyamide resin fibers, wholly aromatic polyamide resin fibers, etc. Synthesis composed of woven or non-woven fabric mainly composed of polyester resin fiber such as polyamide resin fiber, polyester resin fiber, aromatic polyester resin fiber, wholly aromatic polyester resin fiber, polyimide resin fiber, fluororesin fiber, etc. Examples thereof include organic fiber substrates such as fiber substrates, kraft paper, cotton linter paper, and paper substrates mainly composed of linter and kraft pulp mixed paper. Among these, a glass fiber base material is preferable. Thereby, the intensity | strength of the prepreg 12 and a water absorption rate can be improved. Further, the coefficient of thermal expansion of the prepreg 12 can be reduced.

As a method of impregnating the glass cloth with the resin composition in the present embodiment, for example, a method of preparing a resin varnish using the resin composition described above, immersing the glass cloth in the resin varnish, a method of applying with various coaters, The method of spraying with a spray etc. is mentioned. Among these, the method of immersing the glass cloth in the resin varnish is preferable. Thereby, the impregnation property of the resin composition with respect to the glass cloth can be improved. In addition, when immersing a glass cloth in a resin varnish, a normal impregnation coating equipment can be used.

  The solvent used in the resin varnish desirably exhibits good solubility in the resin component in the resin composition, but a poor solvent may be used within a range that does not adversely affect the resin varnish. Examples of the solvent exhibiting good solubility include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve and carbitol.

The solid content of the resin varnish is not particularly limited, but the solid content of the resin composition is 40-8.
0 wt% is preferable, and 50 to 65 wt% is particularly preferable. Thereby, the impregnation property to the glass cloth of a resin varnish can further be improved. The prepreg 12 can be obtained by impregnating the glass cloth with the resin composition and drying at a predetermined temperature, for example, 80 to 200 degrees.

After the preparation of the prepreg 12, the copper foil 23 is stacked on both sides of the prepreg 12, and then heated and pressurized to prepare a double-sided copper-clad laminate 20 (FIG. 2 (b)).
Thereby, the copper clad laminated board excellent in the dielectric property and the mechanical and electrical connection reliability in high temperature and high humidity can be obtained.

  Here, although the copper clad laminated board of this Embodiment laminated | stacked copper foil 23 on the upper and lower surfaces using one prepreg 12, you may pile metal foil or films other than copper foil 23. FIG. Also, two or more prepregs 12 can be laminated. When two or more prepregs 12 are laminated, a metal foil or film is laminated on the outermost upper and lower surfaces or one surface of the laminated prepregs 12. Moreover, although the heating temperature at the time of the said copper clad laminated board preparation is not specifically limited, 120-220 degree | times is preferable and especially 150-200 degree | times is preferable. Moreover, the pressure to pressurize is not particularly limited, but is preferably 2 to 5 MPa, and particularly preferably 2.5 to 4 MPa.

  Examples of the metal constituting the metal foil include copper foil 23, copper alloy, aluminum and aluminum alloy, silver and silver alloy, gold and gold alloy, zinc and zinc alloy, nickel and nickel alloy. , Tin and tin-based alloys, iron and iron-based alloys, and the like. Examples of the film include polyethylene, polypropylene, polyethylene terephthalate, polyimide, and a fluorine resin.

Here, a heat treatment (annealing) at or above the maximum temperature achieved during the curing process of the copper clad laminate is performed on the press clad copper clad laminate. The method for the heat treatment (annealing) is not particularly limited as long as the heat treatment can be performed at a temperature equal to or higher than the highest temperature during the curing process of the copper clad laminate. Examples include a method in which the copper-clad laminate is taken out from the laminating apparatus and heat-treated in an oven, and a method in which pressure and temperature are applied in a state of being sandwiched between press heating plates that are laminating apparatuses. More preferably, in the continuous process following the preparation of the copper-clad laminate, the pressure is controlled at a time of 0 to 9 kg / cm ² for a certain period of time while being sandwiched in a press hot platen, and the maximum reached during the curing process of the copper-clad laminate This is a method of continuously applying a temperature higher than the temperature.
The annealing temperature is preferably higher than the maximum temperature during lamination, that is, the resin curing temperature. By annealing at a temperature equal to or higher than the temperature at the time of press lamination, the strain accumulated by the press is released, so that an effect of suppressing dimensional variation due to subsequent thermal history can be obtained.

After producing the copper-clad laminate, the through-hole 2 is applied to the required location using, for example, a mechanical drill.
After forming 1 (FIG. 2C), a thin electroless copper 24 having a thickness of 1 μm is coated on the inside of the through hole 21 and the surface of the copper foil 23 by electroless copper plating (FIG. 2D). Thereby, the conductor layer 14 (FIG. 1) is formed. Further, panel plating for thickening copper 25 to a thickness of 10 μm or more is performed on the electroless copper 24 on the semiconductor chip mounting surface side described later by electrolytic copper plating (FIG. 2E). In the present embodiment, the electroless copper 24 has a thickness of 1 μm and the copper 25 has a thickness of 10 μm or more, but the present invention is not limited to this.

Next, after a resist 26 is applied to the surface of the copper 25, a mask 27 having a circuit pattern is overlapped and UV exposure is performed (FIG. 2 (f)). For example, when the resist 26 is a positive type, by developing using a developer containing an organic solvent, a portion of the resist 26 that has not been irradiated with UV (non-exposed portion) remains as a wiring pattern (FIG. 2G )).
Thereafter, using the patterned resist 26 as a mask, the exposed portion of the copper 25 is removed by, for example, wet etching (FIG. 2H), and then the resist 26 is peeled off and removed, thereby removing the prepreg 12. A required wiring pattern 15 is formed on the chip mounting side (FIG. 2 (i)).

FIG. 3 is a diagram used for explaining a manufacturing process of a semiconductor device using the interposer 11.
In FIG. 3, first, an adhesive 30 such as an epoxy resin is applied to the semiconductor chip mounting region on the wiring pattern 15 of the interposer 11 (FIG. 3A). Thereafter, the semiconductor chip 31 is bonded to the semiconductor chip mounting region by the adhesive 30 with the back surface of the semiconductor chip 31 to be mounted (the surface opposite to the side where the electrodes are formed) facing down, The electrode and the conductive layer 14 are electrically connected to each other through, for example, an Au bonding wire 32 through the wiring pattern 15 (FIG. 3B).

Next, the semiconductor chip 31 and the bonding wire 32 are sealed with a sealing resin 33, and then the sealing resin 33 is cured by heating (FIG. 3C). Here, the sealing resin 33 may seal at least the upper and side surfaces of the semiconductor chip 31, more specifically, the bonding wires 32. As shown in FIG. 3C, the semiconductor chip mounting surface of the interposer 11 is used. It is not limited to the form which seals the whole surface.
Thereafter, a Pb-free solder ball 34 (melting point: 217 degrees) is placed on the side opposite to the semiconductor chip mounting surface of the interposer 11, and the solder ball 34 is joined to the interposer by performing a reflow process using a reflow device. (FIG. 3D), a semiconductor device is manufactured. In this reflow process, the temperature of the reflow apparatus is set so that the maximum temperature is 260 degrees.

Next, although an example and a comparative example explain the present invention, the present invention is not limited to this.
Example 1
(1) Production of copper clad laminate Novolak-type cyanate resin (Lonza Japan Co., Ltd., Primaset PT-30, average molecular weight of about 700) 19.7 parts by weight, biphenyldimethylene type epoxy resin (Nippon Kayaku Co., Ltd.) NC-3000H, epoxy equivalent 275) 11 parts by weight, biphenyl dimethylene type phenol resin (Maywa Kasei Co., Ltd., MEH-7851-3H, hydroxyl equivalent 230) 9 parts by weight, and epoxy silane type coupling agent (GE Toshiba) Silicone Co., Ltd., A-187) 0.3 parts by weight dissolved in methyl ethyl ketone at room temperature, spherical fused silica (manufactured by Admatechs Co., Ltd., spherical fused silica, SO-25R, average particle size 0.5 μm) 60 wt. Part was added and stirred for 10 minutes using a high-speed stirrer to obtain a resin varnish.
The above-mentioned resin varnish was impregnated into a glass cloth (thickness 94 μm, manufactured by Nitto Boseki Co., Ltd., WEA-2116) and dried for 2 minutes in a 150 ° C. heating furnace to obtain a prepreg having a varnish solid content of about 50% by weight. A copper-clad laminate having a thickness of 0.2 mm was obtained by stacking 18 μm copper foils on both sides of the above prepreg and performing heat-pressure molding at a pressure of 4 MPa and a temperature of 200 degrees for 2 hours. Further, as a heat treatment at a temperature not lower than the highest temperature in the curing process of the copper clad laminate, it was sandwiched in a press hot platen after the curing process and subjected to a pressure of 0.3 Mpa and 240 degrees for 1 hour.
(2) Production of interposer Using the copper clad laminate produced by the above method, an interposer having a wiring pattern and a resist was produced.
(3) Production of Semiconductor Device After mounting a semiconductor chip on the interposer manufactured by the above method and connecting with a bonding wire, the semiconductor chip and the bonding wire are sealed with a thickness of 0.6 mm with a sealing resin. Post mold cure treatment to cure by heating for 4 hours at a temperature, and further Pb-free solder balls (Senju Metal Co., Ltd., melting point 217 degrees) on the surface opposite to the semiconductor chip mounting surface of the interposer Then, a reflow process of heating under the heating conditions of FIG. 4 was performed to obtain a semiconductor device. The secondary mounting was performed, and the drying process of drying at 150 degrees for 8 hours was performed.

<Evaluation method>
<Dimensional change>
About the dimensional change measuring method before and after the reflow process, the copper-clad laminate was cut into a 250 mm square size, and a hole with a diameter of 0.1 mm was formed by drilling in the vicinity of 10 mm inside from the end of the four corners. Next, the distance between the center of two holes parallel to each side was measured and recorded with a precision dimension measuring machine (QUICK VISION QVX404 manufactured by Mitutoyo). This was done for all four sides. Next, reflow treatment was performed in a nitrogen atmosphere at Max 260 degrees. After sufficiently cooling the copper-clad laminate after the reflow process, the distance between the hole centers was measured and recorded with a precision dimension measuring machine as described above. The dimensional change rate was calculated from the distance between the hole centers before the reflow process and the distance between the hole centers after the reflow process. In the evaluation, x was changed by 0.04% or more, and o was 0.04% or less.

<Measurement of linear expansion coefficient>
The above-prepared interposer was cut into a specified size (width 3 mm x length 20 mm), and linear expansion coefficient was displaced in a tensile mode at a temperature increase of 10 ° C / min using a TMA apparatus (TMA2940 manufactured by TA Instruments). The amount was measured. The linear expansion coefficient α1 of Tg or less was determined by the average displacement amount from 50 ° C. to 100 ° C., and the linear expansion coefficient α2 of Tg or more was determined by the average displacement amount of Tg to Tg + 20 ° C.
<Tg measurement>
The glass transition point Tg was measured according to ISO-11359-2. The produced interposer was cut out to a prescribed size (5 mm square), and the displacement in the thickness direction was measured at a temperature increase of 5 ° C./min and in a pushing mode using a TMA apparatus (TAMA2940 manufactured by TA Instruments). . And the tangent of the curve before and behind the glass transition point of the curve which shows temperature and the displacement amount of the thickness of a sample was taken, and the glass transition point was computed from the intersection of this tangent.
<Elastic modulus measurement>
While cutting out the produced interposer into a prescribed size (width 5 mm × length 30 mm) and using a dynamic viscoelasticity measuring device (DMA 2980 manufactured by TA Instruments), the temperature was increased at a rate of 5 ° C./min. Dynamic viscoelasticity was measured by applying a strain of 1 Hz.

<Warpage of semiconductor device>
The amount of warpage before and after the reflow process at the time of manufacturing the semiconductor device was measured by laser scanning. Here, the amount of warpage refers to the height of the surface when both ends of the semiconductor device are used as reference positions, and was calculated from the average value of five samples. The evaluation criteria are shown in Table 1 as x for those that warped, ○ for those that did not warp, ○ for those that could be joined after secondary mounting, and x for those that could not.

(Examples 2 and 3)
The pressure 0.3 Mpa, 240 degrees 1 hour, which is a heat treatment condition higher than the highest temperature in the curing process of the copper clad laminate produced in Example 1, is changed. In Example 2, the pressure 0.3 Mpa, 220 degrees 1 hour is changed. In Example 3, heat treatment (no load) was performed in an oven at 220 ° C. for 1 hour instead of the press hot platen. Otherwise, an interposer and a semiconductor device were produced in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
(Comparative Example 1)
As a heat treatment at or above the maximum temperature achieved in the curing step of the copper clad laminate produced in Example 1, the treatment at 240 degrees 1 hour was changed, the treatment at 220 degrees 1 hour in Example 2, and 220 degrees in Example 3. Heat treatment was performed in an oven for 1 hour. Otherwise, an interposer and a semiconductor device were produced in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
(Comparative Example 2)
In the production of the copper-clad laminate of Example 1, a copper-clad laminate that is not subjected to heat treatment at a temperature higher than the highest temperature in the curing process after the curing process of the copper-clad laminate is used. An interposer and a semiconductor device were prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

It is sectional drawing of the interposer manufactured by the manufacturing method which concerns on embodiment of this invention. It is a figure used for demonstrating the manufacturing process of the interposer of FIG. It is a figure used for demonstrating the manufacturing process of the semiconductor device using an interposer. It is a graph which shows the heating temperature profile at the time of heat processing.

Explanation of symbols

11 Interposer 12 Prepreg 14 Conductor Layer 15 Wiring Pattern

Claims (6)

In a semiconductor device manufactured using a printed wiring board for a semiconductor device having a plurality of layers of conductor circuits, the dimensional change before and after the reflow process of the printed wiring board for a semiconductor device is 0.04% or less. Semiconductor device. 2. The semiconductor device according to claim 1, wherein an average linear expansion coefficient at a glass transition temperature (Tg) or lower of the printed wiring board for a semiconductor device is 3 ppm / ° C. or higher and 12 ppm / ° C. or lower. The semiconductor device according to claim 1 or 2, wherein the printed circuit board for a semiconductor device has an elastic modulus at room temperature of 1 GPa to 30 GPa. 4. The semiconductor device according to claim 1, wherein the printed wiring board for a semiconductor device is manufactured using a copper-clad laminate including at least a cyanate resin, an epoxy resin, and a curing agent. . A printed wiring board for a semiconductor device, which is used in any one of claims 1 to 4. The copper clad laminated board used for any one of Claims 1-4.

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