Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
  • H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
  • H01L21/563—Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
  • H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
  • H01L23/293—Organic, e.g. plastic
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/22—Secondary treatment of printed circuits
  • H05K3/28—Applying non-metallic protective coatings
  • H05K3/284—Applying non-metallic protective coatings for encapsulating mounted components
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
  • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
  • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
  • H05K3/341—Surface mounted components
  • H05K3/3431—Leadless components
  • H05K3/3436—Leadless components having an array of bottom contacts, e.g. pad grid array or ball grid array components
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
  • H01L2224/10—Bump connectors; Manufacturing methods related thereto
  • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
  • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
  • H01L2224/161—Disposition
  • H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
  • H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
  • H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
  • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
  • H01L2224/31—Structure, shape, material or disposition of the layer connectors after the connecting process
  • H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
  • H01L2224/321—Disposition
  • H01L2224/32151—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
  • H01L2224/32221—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
  • H01L2224/32225—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
  • H01L2224/732—Location after the connecting process
  • H01L2224/73201—Location after the connecting process on the same surface
  • H01L2224/73203—Bump and layer connectors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
  • H01L2224/732—Location after the connecting process
  • H01L2224/73201—Location after the connecting process on the same surface
  • H01L2224/73203—Bump and layer connectors
  • H01L2224/73204—Bump and layer connectors the bump connector being embedded into the layer connector
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/01—Chemical elements
  • H01L2924/01019—Potassium [K]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/06—Polymers
  • H01L2924/078—Adhesive characteristics other than chemical
  • H01L2924/0781—Adhesive characteristics other than chemical being an ohmic electrical conductor
  • H01L2924/07811—Extrinsic, i.e. with electrical conductive fillers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
  • H01L2924/151—Die mounting substrate
  • H01L2924/153—Connection portion
  • H01L2924/1531—Connection portion the connection portion being formed only on the surface of the substrate opposite to the die mounting surface
  • H01L2924/15311—Connection portion the connection portion being formed only on the surface of the substrate opposite to the die mounting surface being a ball array, e.g. BGA
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
  • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
  • H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
  • H05K2201/10954—Other details of electrical connections
  • H05K2201/10977—Encapsulated connections
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/17—Post-manufacturing processes
  • H05K2203/176—Removing, replacing or disconnecting component; Easily removable component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

• This invention relates to a structure and process for mounting a semiconductor chip, such as large scale integration (“LSI”), on a carrier substrate.
• LSI large scale integration
• the CSP/BGA assembly is connected to electrical conductors on a circuit board by use of a solder connection or the like.
• a solder connection or the like.
• the reliability of the solder connection between the circuit board and the CSP/BGA often becomes suspect.
• a sealing resin often referred to as underfill sealing
• thermosetting resins are typically used as the underfill sealing material, in the event of a failure after the CSP/BGA assembly is mounted on the circuit board, it is very difficult to replace the CSP/BGA assembly without destroying or scrapping the structure in its entirety.
• Japanese Laid-Open Patent Publication No. 69280/94 discloses a process where a bare chip is fixed and connected to a substrate by use of a resin capable of hardening at a predetermined temperature. In the event of failure, this bare chip is removed from the substrate by softening the resin at a temperature higher than the predetermined temperature.
• no specific resin is disclosed, and there is no disclosure about treating the resin which remains on the substrate. Thus, the disclosed process is at best incomplete .
• Japanese Patent Laid-Open No. 251516/93 also discloses a mounting process using bisphenol A type epoxy resin (CV5183 or CV5183S; manufactured by Matsushita Electric Industrial Co., Ltd.).
• CV5183 or CV5183S manufactured by Matsushita Electric Industrial Co., Ltd.
• the removal process so disclosed does not consistently permit easy removal of the chip, the curing step is lengthy at elevated temperatures, and the process generally results in poor productivity .
• the present invention provides a mounting structure for semiconductor devices which enables a semiconductor device (such as a CSP/BGA assenbly) which includes a semiconductor chip mounted on a carrier substrate, to be securely connected to a circuit board by short-time heat curing and with good productivity, which demonstrates excellent heat shock properties (or thermal cycle properties) , and permits the CSP/BGA assembly to be easily removed from the circuit board in the event of semiconductor device or connection failure.
• a semiconductor device such as a CSP/BGA assenbly
• the present invention also provides a method for repairing such a mounting structure.
• the mounting structure includes a semiconductor device, which itself includes a semiconductor chip mounted on a carrier substrate, and a circuit board to which the semiconductor device is electrically connected.
• the space between the carrier substrate of the semiconductor device and the circuit board is sealed with a reaction product of a thermosetting resin composition.
• This composition includes about 100 parts by weight of an epoxy resin, about 3 to about 60 parts by weight of a curing agent and about 1 to about 90 parts by weight of a plasticizer.
• the present invention also relates to a mounting process for a semiconductor device, the steps of which include electrically connecting a. semiconductor device to a circuit board; infiltrating a thermosetting resin composition into the space between the carrier substrate of the semiconductor device having a semiconductor chip mounted on a carrier substrate and the circuit board; and curing the thermosetting resin composition by the application of heat .
• the mounting process of the present invention may further include the steps of testing electrical properties of the circuit board on which the semiconductor device is mounted; in the event of failure in the testing step, removing the semiconductor device at the failure site while heating the neighborhood of the failure site; removing the residue of the reaction product of the thermosetting resin composition from the circuit board or from the bottom of the semiconductor device by heating it to a predetermined temperature, impregnating it with an organic solvent, with or without the application of heat at a predetermined temperature; and removing the residue of the electrically conductive material from the circuit board or from the bottom of the semiconductor device. In this way, the defective part can be repaired.
• thermosetting resin composition used in the present invention is curable at a relatively low temperature in a short period of time, cured reaction products thereof exhibit excellent heat shock properties and, moreover, may be easily split by the application of force under heated conditions. Further, the cured reaction products attached to circuit boards and the like may be easily removed by heating, swelling with a solvent, or swelling with a solvent under heated conditions.
• thermosetting resin composition semiconductor devices, such as CSP/BGA assemblies, can be securely connected to a circuit board by short-time heat curing and with good productivity, and the resulting mounting structure has excellent heat shock properties (or thermal cycle properties) . Moreover, in the event of failure, the semiconductor device can be easily removed. This facilitates reuse of the semiconductor device or circuit board, thereby achieving an improvement in the yield of the production process and a reduction in production cost .
• FIG. 1 depicts a cross-sectional view showing an example of the mounting structure of the present invention.
• FIG. 2 depicts a cross-sectional view of a semiconductor device which has been removed from the circuit board for repairing purposes according to the present invention.
• the semiconductor device 4 used in the present invention is one formed by connecting a semiconductor chip ("bare chip") 2, such as LSI, to a carrier substrate 1 and, sealing the space therebetween with resin 3.
• This semiconductor device is mounted at a predetermined position of the circuit board 5, and electrodes 8 and 9 are electrically connected by a suitable connection means, such as solder.
• a suitable connection means such as solder.
• the space between carrier substrate 1 and circuit board 5 is sealed with a thermosetting resin composition which is then cured into a reaction product 10.
• the cured reaction product 10 of the thermosetting resin composition need not completely fill the space between carrier substrate 1 and circuit board 5, but should fill that space to such an extent as to relieve stresses caused by thermal cycles.
• Carrier substrates may be constructed from ceramic substrates made of Al 2 0 3 , SiN 3 and mullite (Al 2 0 3 -Si0 2 ) ; substrates or tapes made of heat-resistant resins such as polyimides; glass-reinforced epoxy, ABS and phenolic substrates which are also used commonly as circuit boards; and the like.
• the means for electrically connecting the semiconductor chip to the carrier substrate may be employed connection by a high-melting solder or electrically (or anisotropically) conductive adhesive, wire bonding, and the like.
• the electrodes may be formed as bumps.
• the space between the semiconductor chip and the carrier substrate may be sealed with a suitable resin.
• the semiconductor devices which can be used in the present invention include CSPs and BGAs.
• circuit board used in the present invention No particular limitation is placed on the type of circuit board used in the present invention, and there may be used any of various common circuit boards such as glass-reinforced epoxy, ABS and phenolic boards.
• thermosetting resin composition which is used as a sealer underfilling between such a semiconductor device and a circuit board to which the semiconductor device is electrically connected, includes about 100 parts by weight of an epoxy resin, about 3 to about 60 parts by weight of a curing agent, and about 1 to about 90 parts by weight of a plasticizer .
• the epoxy resin used in the present invention can be any common epoxy resin.
• This epoxy resin may comprise at least one multifunctional epoxy resin and 0 to 30%, such as 20%, by weight based on the total epoxy resin of at least one monofunctional epoxy resin used as a reactive diluent, or crosslink density modifier.
• the multifunctional epoxy resin examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol-novolac type epoxy resin cresol-novolac type epoxy resin and appropriate combinations thereof. Consideration should be given to the viscosity and other properties of the epoxy resin, and ordinarily the multifunctional epoxy resin should include an amount within about the range of 10 to 100%, of bisphenol A type epoxy resin. Desirably, the amount of bisphenol A type resin should be in the range of from about 50 to 100%.
• the monofunctional epoxy resin has one epoxy group.
• the epoxy group should have an alkyl group of about 6 to about 28 carbon atoms, examples of which include C 6 -C 28 alkyl glycidyl ethers, C 6 -C 28 fatty acid glycidyl esters and C 6 -C 28 alkylphenol glycidyl ethers.
• the plasticizer used in the present invention is one which has relatively low volatility as characterized by a boiling point of at least about 130 °C and which lowers the Tg of cured reaction products of the resin. It is desirable to use a plasticizer material which causes microscopic phase separation when the resin is cured. While these materials are referred to herein as plasticizers , they need not perform the function (s) conventionally associated with plasticizers .
• plasticizers examples include butylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, n-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co-co
• (Meth) acrylic esters useful as plasticizers in this invention include monofunctional (meth) acrylic esters, such as (meth) acrylic esters of straight-chain or branched aliphatic alcohols, (meth) acrylic esters of aliphatic alcohols having an aromatic hydrocarbon substituent group,
• (meth) acrylic esters of hydroxy aliphatic amines and multifunctional (meth) acrylic esters, such as (meth) acrylic esters of polyethers and (meth) acrylic esters of polyhydric epoxy compounds .
• (Meth) acrylic esters of straight-chain or branched aliphatic alcohols useful as plasticizers in this invention include those with about 4 to about 16 carbon atoms, such as n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl
• (meth) acrylate 2-ethylhexyl (meth) acrylate , ⁇ -octyl (meth) acrylate , isodecyl (meth) acrylate , lauryl (meth) acrylate, tridecyl (meth) acrylate , tetradecyl (meth) acrylate and cetyl (meth) acrylate .
• (Meth) acrylic esters of aliphatic alcohols having an aromatic hydrocarbon substituent group include (meth) acrylic esters of aliphatic alcohols having from 1 to about 8 carbon atoms having an aromatic hydrocarbon substituent group, such as benzyl (meth) acrylate .
• (Meth) acrylic esters of alicyclic alcohols useful as plasticizers in this invention include cyclohexyl (meth) acrylate and isobornyl (meth) acrylate .
• Hydroxyl-containing alkyl (meth) acrylic esters useful as plasticizers in this invention include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) crylate and 3 -phenoxy-2 -hydroxypropyl (meth) acrylate .
• (Meth) acrylic esters of hydroxy aliphatic amines useful in this invention include (meth) acrylic esters of amines represented by NR 1 R 2 R 3 where R 1 , R 2 and R J independently represent hydrogen, alkyl groups, hydroxyalkyl groups or hydro-poly (oxyalkylene) groups, and at least one of R 1 , R 2 and R 3 is a hydroxyalkyl group or a hydro-poly (oxyalkylene) group .
• Examples of (meth) acrylic esters of polyethers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate and trimethylolpropane tri (meth) acrylate .
• Examples of the (meth) acrylic esters of polyhydric epoxy compounds include di (meth) acrylic esters of bisphenol A epichiorohydrin reaction products-.
• Aromatic or aliphatic esters useful as plasticizers in the present invention include dialkyl esters of aromatic carboxylic acids, e.g., di (C 1 -C 12 alkyl) phthalates, such as dimethyl phthalate, diethyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate and octyl decyl phthalate; aliphatic monobasic acid esters, such as butyl oleate and glycerol mono-oleate; and aliphatic dibasic acid esters, such as dibutyl adipate, di-2-ethylhexyl adipate, dibutyl sebacate and di-2-ethylhexyl sebacate.
• di (C 1 -C 12 alkyl) phthalates such as dimethyl phthalate, diethyl phthalate, di-n-octyl phthalate, di-2-
• (meth) acrylic esters of alkanolamines or hydro-poly (oxyalkylene) amines as represented by the formula above, di(C 1 -C 12 alkyl) phthalates, hydroxyl-containing alkyl esters of (meth) acrylic acid, and (meth) acrylic esters of alicyclic alcohols are especially desirable.
• the plasticizer component is usually used in an amount of 1 to about 90 parts by weight, per 100 parts by weight of the epoxy resin. Desirably, that range is within 5 to 50 parts by weight of the resin.
• thermosetting resin composition of the present invention may be formulated as a one-part composition, in which all the ingredients are mixed together, or as a two-part composition, in which the epoxy resin and the curing agent are stored separately and mixed thereafter prior to use.
• the curing agent used in the present invention can generally be any of the curing agents which are used in one-part and two-part epoxy resins.
• desirable curing agents for use with the present invention include amine compounds, imidazole compounds, modified amine compounds and modified imidazole compounds.
• amine compounds include dicyandiamide; aliphatic polyamihes, such as diethylenetriamine, triethylenetetramine and diethylaminopropylamine ; aromatic polyamines, such as m-xylenediamine and diaminodiphenylamine ; alicyclic polyamines, such as isophoronediamine and menthenediamine ; and polyamides.
• Examples of the imidazole compounds include 2 -methyl imidazole, 2-ethyl-4-methylimidazole and 2-phenylimidazole .
• Examples of the modified amine compounds include epoxy-added polyamines formed by the addition' of an amine compound to an epoxy compound, and examples of the modified imidazole compounds include imidazole adducts formed by the addition of an imidazole compound to an epoxy compound.
• latent curing agents used in one-pack epoxy resins are particularly desirable. From the viewpoint of repairability, it is especially desirable to use 5 to 95% by weight of a modified amine in combination with 95 to 5% by weight of dicyandiamide, based on the total weight of the curing agent.
• the curing agent itself is ordinarily used in an amount of from about 3 to about 60 parts by weight, per 100 parts by weight of the epoxy resin. Desirably, that is within 5 to 40 parts by weight of the resin.
• -lilt is desirable for the thermosetting resin compositions used in the present invention to contain the aforesaid plasticizer and monofunctional epoxy resin in a combined amount of about 5 to about 40% by weight.
• thermosetting resin compositions according to the present invention are capable of penetrating into the space between the circuit board and the semiconductor device. These inventive compositions also demonstrate a reduced viscosity, at least under elevated temperature conditions, and thus are capable of penetrating into that space. It is desirable to prepare the thermosetting resin composition by selecting the types and proportions of various ingredients so that its viscosity at 25°C will be 50,000 mPa • s or less, such as 30,000 mPa • s or less, so as to improve its ability to penetrate into the space (e.g. , of 100 to 200 ⁇ m) between the circuit board and the semiconductor device.
• thermosetting resin composition of the present invention may further contain other additives, such as defoaming agents, leveling agents, dyes, pigments and fillers.
• photopolymerization initiators may also be incorporated therein, provided that such initiators do not adversely affect the properties of the composition or reaction products formed therefrom.
• cream solder is printed at the necessary positions of a circuit board and suitably dried to expel the solvent.
• a semiconductor device is mounted in conformity with the pattern on the circuit board. This circuit board is passed through a reflowing furnace to melt the solder and thereby solder the semiconductor device.
• the electrical connection between the semiconductor device and the circuit board is not limited to the use of cream solder, but may be made by use of solder balls. Alternatively, this connection may also be made through an electrically conductive adhesive or an anisotropically conductive adhesive. Moreover, cream solder or the like may be applied or formed on either the circuit board or the semiconductor device.
• solder, electrically or anisotropically conductive adhesive used should be chosen bearing in mind its melting point, bond strength and the like.
• the resulting structure should ordinarily be subjected to a continuity test or the like. After passing such test, the semiconductor device with a resin composition. In this way, in the event of a failure, it is easier to remove the semiconductor device before fixing it with the resin composition .
• thermosetting resin composition is applied to the periphery of the semiconductor device.
• a thermosetting resin composition is applied to the semiconductor device, it penetrates into the space between the circuit board and the carrier substrate of the semiconductor device by capillary action.
• thermosetting resin composition is cured by the application of heat.
• the thermosetting resin composition shows a significant reduction in viscosity and hence an increase in fluidity, so that it more easily penetrates into the space between the circuit board and the .semiconductor device.
• the thermosetting resin composition is allowed to penetrate fully into the entire space between the circuit board and the semiconductor device.
• thermosetting resin composition applied should be suitably adjusted so as to fill the space between the circuit board and the semiconductor device almost completely.
• thermosetting resin composition When the above-described thermosetting resin composition is used, it is usually cured by heating at 120 to 150°C for a period of time of about 5 to 20 minutes. Thus , the present invention can employ relatively low-temperature and short -time curing conditions and hence achieve very good productivity.
• the mounting structure illustrated in FIG. 1 is completed in this manner. Where a (meth) acrylic ester is used as a plasticizer in the thermosetting resin composition and a photopolymerization initiator is added thereto, the thermosetting resin composition can be tentatively cured by exposure to light prior to heat curing.
• repair can be made in the following manner.
• the area around the semiconductor device at the failure site is heated at a temperature of about 190 to about 260°C for a period of time ranging from about 10 seconds to about 1 minute.
• the heating means local heating is preferred.
• the semiconductor device is pulled apart .
• a residue 12 of the cured reaction product of the thermosetting resin composition and a residue 14 of the solder are left on the circuit board 5.
• the residue of the cured reaction product of the thermosetting resin composition can be removed, for example, by scraping it off after the residue has been softened by heating it to a predetermined temperature, allowing it to swell with solvent, or allowing it to swell with solvent while heating it to a predetermined temperature.
• the residue can be scraped off after it has been softened by allowing the residual resin to swell with solvent while keeping the entire circuit board at a temperature of the order of 100°C (usually in the range of 80 to 120°C) .
• the solvent used for this purpose is one which causes the cured reaction products of the thermosetting resin composition to swell, thereby reducing bond strength to such an extent that the cured material can be scraped off from the circuit board.
• Useful solvents include organic ones, for example, alkyl chlorides such as methylene chlorlide; glycol ethers, such as ethyl cellulose and butyl cellulose; diesters of dibasic acids, such as diethyl succinate; and N-methylpyrrolidone . Of course, appropriate combinations may also be employed.
• the- chosen solvents should cause no damage to the resist.
• Desirable solvents include glycol ethers and N-methylpyrrolidone.
• the residue of the solder can be removed, for example, by use of a solder-absorbing braided wire.
• the semiconductor device can be reused by removing the residue 13 of the cured reaction product of the thermosetting resin composition and the residue 15 of the solder left on the bottom of the semiconductor device in the same manner as described above.
• thermosetting resin composition was prepared by mixing the epoxy resins (i), curing agents (ii) and plasticizer (iii) in the amounts described below, and 0.1 parts by weight of a defoaming agent.
• the viscosity of the so-formed composition was observed to be 5,200 MPa • s .
• epoxy resins 85 parts by weight of bisphenol A type epoxy resin, 4 parts by weight of novolac epoxy resin, and 11 parts by weight of a mixture of alkyl glycidyl ethers of 12 to 14 carbon atoms.
• curing agents 3 parts by weight of dicyandiamide, and 19 parts by weight of an epoxy adduct of an amine .
• plasticizer 12 parts by weight of an acrylated amine oligomer.
• thermosetting resin composition was applied to the periphery of the CSP by means of a dispenser, and then cured by heating at 150°C for a period of time of about 5 minutes. During this procedure, the thermosetting resin composition penetrated into the space between the semiconductor device and the circuit board before curing completely.
• the area around the CSP fixed to the circuit board with the thermosetting resin composition as described above was heated by applying hot air at 250°C for 1 minute. Then, the CSP could be easily removed by inserting a metal piece between the CSP and the glass-reinforced epoxy board, and lifting the CSP.
• the glass-reinforced epoxy board was kept at about 100 °C by placing it on a hot plate (or by heating it with a far-infrared heater or the like) , the resin left on the glass-reinforced epoxy board was allowed to swell with a solvent such as PS-1 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) or 7360 (manufactured by Loctite Corporation), and then scraped off with a spatula. The solder left on the glass-reinforced epoxy board was removed by use of a solder-absorbing braided wire. The time required for this repairing operation was within 3 minutes, which was sufficiently short from a practical point of view.
• PS-1 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.
• 7360 manufactured by Loctite Corporation
• Cream solder was applied again to the glass-reinforced epoxy board from which the CSP had been removed in the above-described manner, and a new CSP was mounted thereon. In this operation, cream solder may be printed on the new CSP.
• the thermosetting resin composition was applied to the periphery of the CSP and then cured by heating at 150 °C for 5 minutes.
• Example 1 The procedure of Example 1 was repeated except that the amount of the acrylated amine oligomer used as a plasticizer in Example 1 was altered as shown below. The resulting mounting structures passed a heat shock test, and their repair time was within 3 minutes.
• Example 2 1.2 parts by weight.
• Example 3 6.0 parts by weight.
• Example 1 The procedure of Example 1 was repeated except that no plasticizer was used.
• the resulting mounting structure exhibited acceptable repairability, but did not pass a heat shock test because continuity was lost at less than 1,000 cycles.
• Example 1 The procedure of Example 1 was repeated except that the amount of the acrylated amine oligomer used as a plasticizer in Example 1 was altered to 120 parts by weight The resulting mounting structure exhibited acceptable repairability, but did not pass a heat shock test because continuity was lost at less than 1,000 cycles.
• Example 6-9 The procedure of Example 1 was repeated except that the amount of the mixture of alkyl glycidyl ethers of 12 to 14 carbon atoms used in Example 1 was altered as shown below. The resulting mounting structures passed a heat shock test, and their repair time was within 3 minutes.
• Example 6 0 part by weight.
• Example 7 2.7 parts by weight.
• Example 8 5.3 parts by weight
• Example 9 20.0 parts by weight.
• Example 1 The procedure of Example 1 was repeated except that the amount of the mixture of alkyl glycidyl ethers of 12 to 14 carbon atoms used in Example 1 was altered to 40 parts by weight.
• the resulting mounting structure exhibited acceptable repairability, but did not pass a heat shock test because continuity was lost at less than 1,000 cycles.
• Example 1 The procedure of Example 1 was repeated except that the acrylated amine oligomer used as a plasticizer in Example 1 was replaced by each of- the compounds shown below.
• the resulting mounting structures passed a heat shock test, and their repair time was within 3 minutes.
• Example 10 DOP (dioctyl phthalate)
• Example 11 Isobornyl acrylate.
• Example 12 2-Hydroxyethyl methacrylate
• Example 2 The procedure of Example 1 was repeated except that the epoxy adduct of amine used as a curing agent in Example 1 was replaced by the epoxy adduct of imidazole. The resulting mounting structure passed a heat shock test, and its repair time was within 3 minutes. Comparative Example 4
• Example 1 The procedure of Example 1 was repeated except that, in place of the thermosetting resin composition used in Example 1, an adhesive (TB3006B; manufactured by Three Pond Co., Ltd.) comprising acrylate oligomers, acrylate monomers and a photopolymerization initiator was used and cured by exposure to light through the gap between the semiconductor device and the circuit board and by the application of heat.
• an adhesive (TB3006B; manufactured by Three Pond Co., Ltd.) comprising acrylate oligomers, acrylate monomers and a photopolymerization initiator was used and cured by exposure to light through the gap between the semiconductor device and the circuit board and by the application of heat.
• this adhesive was used, the semiconductor device could be easily removed in its semicured state. After the adhesive was completely cured, the resulting mounting structure was subjected to a heat shock test. Its heat shock properties were unacceptable because continuity was lost at less than 1,000 cycles.
• Example 1 The procedure of Example 1 was repeated except that in place of the thermosetting resin composition used in Example 1, an epoxy resin sealant (SA-51-2; manufactured by Asahi Kaken Co., Ltd.) was applied in the same manner as in Example 1 and cured by heating at 100° for 90 seconds. In a heat shock test, the resulting mounting structure exhibited the same degree of reliability as in Example 1. However, an attempt was made to separate the semiconductor device by the application of heat for repairing purposes, but in vain. The full scope of the invention is measured by the claims .
• SA-51-2 epoxy resin sealant manufactured by Asahi Kaken Co., Ltd.

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• 1997
  • 1997-01-17 JP JP00657597A patent/JP3543902B2/ja not_active Expired - Fee Related
• 1998
  • 1998-01-16 WO PCT/US1998/000856 patent/WO1998032159A2/en active IP Right Grant
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