MXPA99006673A - Mounting structure and mounting process from semiconductor devices - Google Patents

Abstract

The present invention provides a mounting structure for semiconductor devices which enables a semiconductor device, such as CSP/BGA, to be securely fixed to a circuit board by short-time heat curing, which exhibits good productivity, and excellent heat shock properties (or thermal cycle properties), and which permits the semiconductor device to be easily removed from the circuit board in the event of failure. This invention also provides a mounting process for semiconductor devices.

Description

ASSEMBLY STRUCTURE AND ASSEMBLY PROCESS OF SEMICONDUCTOR DEVICES BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a structure and process for mounting a semiconductor chip, such as a large scale integration device ("LSI") on a carrier substrate. Brief Description of Related Technology In recent years, the popularity of small-sized electronic devices, such as video tape recorders with integrated camera ("VTRs") and portable telephone devices, has made it desirable to reduce the size of electronic devices. large-scale integration. As a result of these reduction needs, chip size or chip size ("CSPs") and dial grid arrays ("BGAs") are being used to reduce the size of the packets substantially to that of bare chips.

Such chip-size packages and dial grid matrices improve the characteristics of the electronic device while retaining many of its operational functions, thus serving to protect bare semiconductor chips, such as large-scale integration devices and facilitate testing of the devices. same. Commonly, the chip-size / grid-matrix array package is connected to electrical conductors in a circuit board by the use of a welding connection or the like. However, when the resulting structure is exposed to thermal cycling, the reliability of the solder connection between the circuit board and the chip-size / grid-matrix array package is doubtful. Recently, after the chip-size / grid-matrix array package is mounted on a circuit board, the space between the chip-size / grid-matrix array package and the circuit board is commonly filled with a sealant resin (commonly called filler sealant) to release stresses produced by thermal cycling, thus improving thermal impact properties and improving the reliability of the structure. However, as heat-resistant resins are typically used as the filler sealant material, in the case of a failure after a chip-size / grid-matrix array assembly is mounted on the circuit board, it is very Difficult to replace the chip size package / grid matrix of the array without destroying or scraping the structure completely. For that purpose, the techniques for mounting a bare chip on a circuit board are accepted as substantially similar to mounting a chip size pack / sphere grid array on a circuit board. One of these techniques, disclosed in Japanese Patent Laid-Open No. 102343/93, includes a mounting process in which a bare chip is fixed and connected to a circuit board by the use of a photocurable adhesive, wherein, in In case of failure, this naked chip is removed from it. However, this technique is limited to cases where the circuit board includes a transparent substrate (eg, glass) that allows exposure to light from the back, and the resulting structure exhibits poor heat impact properties . Japanese Patent Laid-open Publication No. 69280/94 discloses a process wherein a bare chip is fixed and connected to a substrate by the use of a resin capable of hardening at a predetermined temperature. In the case of failure, this bare chip is removed from the substrate by softening the resin at a temperature higher than the predetermined temperature. However, a specific resin is not disclosed, and there is no disclosure about the treatment of the resin remaining in the substrate. Thus, the disclosed process is incompatible. As noted in Japanese Patent Laid-open No. 77264/94, it is conventional to use a solvent to remove residual resin from the circuit board. Nevertheless, dilate the resin with a solvent is a process that takes time and the corrosive organic acid that is commonly used as a solvent can reduce the reliability of the circuit board. Instead of so, that disclosure speaks of a method to remove residual resin by irradiation with electromagnetic radiation. Japanese Patent Laid-Open No. 251516/93 also discloses a mounting process using an epoxy resin of biphenol A type (CV5183 or CV5183S; manufactured by Matsushita Electric I ndustrial Co., Ltd.). However, the described removal process does not allow easy and consistent removal of the chip, the curing step is long at high temperatures and the process generally results in poor productivity. Accordingly, it would be desirable to have a mounting surface for semiconductor devices that is easily removed in case of failure and a process for manufacturing such a structure. Brief Description of the Invention The present invention provides a mounting structure for semiconductor devices that allows secure connection of a semiconductor device (such as a chip size packet / sphere grid array) that includes a semiconductor chip mounted in the semiconductor device. a carrier substrate, to a circuit board by heat curing for a short time and with good productivity, which demonstrates excellent thermal impact properties (or thermal cycle properties) and allows to easily remove the chip / matrix size packet set of the grid grid of the circuit board in the event of a connection failure or of the semiconductor device. The present invention also provides a method for repairing such a mounting structure. The mounting structure includes a semiconductor device, which in turn 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 of a plasticizer. The present invention also relates to a mounting process for a semiconductor device, whose steps include electrically connecting a semiconductor device to a circuit board; injecting 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 thermoinduring resin composition by the application of heat. After the semiconductor device is mounted, the assembly process of the present invention may additionally include the steps of testing the electrical properties of the circuit board on which the semiconductor device is mounted; in the case of failure in the test step, remove the semiconductor device at the fault location while heating the proximity of the fault site; removing the residue of the reaction product from the thermosetting resin composition of 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. Although the thermosetting resin composition used in the present invention can be cured at a relatively low temperature in a short period of time, the cured reaction products thereof exhibit excellent thermal impact properties and, in addition, can be easily divided by the application of force bao heat conditions. Additionally, cured reaction products attached to circuit boards and the like can be easily removed by heating, dilation with a solvent or dilation with a solvent under heating conditions. When using a thermosetting resin composition, semiconductor devices, such as chip size package / dial grid matrix 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 properties of thermal impact (or thermal cycle properties). Additionally, in the case of a fault, the semiconductor device can be easily removed. This makes it easier to reuse the semiconductor device or circuit board, thereby improving the performance of the production process and a reduction in the cost of production. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more readily appreciated with reference to the figures indicated below. Figure 1 shows a cross-sectional view showing an example of the mounting structure of the present invention. Figure 2 shows a cross-sectional view of a semiconductor device that has been removed from the circuit board for repair purposes in accordance with the present invention. Detailed Description of the Invention Figure 1 shows an example of the mounting structure of 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 a large-scale integration device, to a carrier substrate 1 and sealing the space therebetween. resin 3. This semiconductor device is mounted to a predetermined position of circuit board 5, and electrodes 8 and 9 are electrically connected by a suitable connection means, such as welding. To improve reliability, the space between the carrier substrate 1 and the circuit board 5 is sealed with a thermosetting resin composition which is then cured in a reaction product 10. The cured reaction product 10 of the thermosetting resin composition does not it has to completely fill the space between the carrier substrate 1 and the circuit board 5, but it must fill that space to such a degree that it releases the stresses caused by thermal cycles. The carrier substrates can be constructed of ceramic substrates made of Al203, SiN3 and mullite (Al203-Si02); substrates or tapes made with heat resistant resins, such as polyimides; epoxy reinforced with fiberglass, ABS and phenolic substrates that are also commonly used as circuit boards; and similar. There is no particular limitation as to the means for electrically connecting the semiconductor chip and the carrier substrate and the connection can be employed by a high melting solder or an electrically (or anisotropically) conductive adhesive, wire bonding and the like. To facilitate connections, the electrodes can be formed as protuberances. Additionally, to improve the reliability and durability of the connections, the space between the semiconductor chip and the carrier substrate can be sealed with a suitable resin. Semiconductor devices that can be employed in the present invention include chip size packages and sphere grid matrices. There is no particular limitation on the type of circuit board used in the present invention and any of the various circuit boards such as epoxy reinforced with glass fiber, ABS and phenolic boards can be used. The thermosetting resin composition which is used as a filler sealant between said 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 hardening 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 from 0 to 30%, such as 20% by weight based on the total epoxy resin of at least one single-function epoxy resin used as the reactive diluent, or degraded density modifier. Examples of the multifunctional epoxy resin include biphenol A type epoxy resin, bifenol F type epoxy resin, phenol novolac type epoxy resin, cresol-novolac type epoxy resin and appropriate combinations thereof. The viscosity and other properties of the epoxy resin should be considered, and commonly the epoxy resin should include an amount within about the range of 10 to 100% biphenol type epoxy resin A. Desirably, the amount of biphenol type epoxy resin A should be in the range of approximately 50 to 100%. The single-function epoxy resin has an epoxy group.

Commonly, the epoxy group should have an alkyl group of about 6 to about 28 carbon atoms, examples of which include C4-C28 glycidyl alkyl ethers, C3-C28 glycidyl fatty acid esters and C6-C28-alkynediol glycidyl ethers. The plasticizer used in the present invention is one which has a relatively low volatility characterized by a boiling point of at least about 130 ° C and which reduces the Tg of the cured reaction products of the resin. It is desirable to use a plasticizer material that produces microscopic phase separation when the resin hardens. Although these materials are referred to herein as plasticizers, they do not have to perform the function or functions conventionally associated with the plasticizers. Examples of such plasticizers include (meta) acrylic esters, and aromatic or aliphatic esters. The (meta) acrylic esters useful as plasticizers in this invention include monofunctional (meta) acrylic esters, such as (meta) acrylic esters of straight or branched chain aliphatic alcohols, (meta) acrylic esters of aliphatic alcohols having a substituent group of aromatic hydrocarbon, (meta) acrylic esters of alicyclic alcohols, alkyl- (meta) acrylic esters containing hydroxyl and (meta) acrylic esters of hydroxyaliphatic amines; and multifunctional (meta) acrylic esters, such as (meta) acrylic esters of polyethers and (meta) acrylic esters of epoxy polyhydric compounds.

(Meta) acrylic esters of straight or branched chain aliphatic alcohols useful as plasticizers in this invention include those having about 4 to about 16 carbon atoms, such as n-butyl (meta) acrylate, isobutyl (meth) acrylate, t -butyl (meta) acrylate, 2-ethylhexyl (meta) acrylate, n-octyl I (meta) acrylate, isodecyl (meta) acrylate, laurii (meta) acrylate, tridecyl (meta) acrylate, tetradecyl (meta) ) acrylate and cetyl (meta) acrylate. (Meta) acrylic esters of aliphatic alcohols having an aromatic hydrocarbon substituent group include (meta) acrylic esters of aliphatic alcohols having from 1 to about 8 carbon atoms having an aromatic hydrocarbon substituent group, such as benzyl (meta acrylate. The (meta) acrylic esters of aliphatic alcohols useful as plasticizers in this invention include cyclohexyl (meta) acrylate and triethyl (meta) acrylate. Alkyl (meta) acrylic esters containing hydroxyl useful as plasticizers in this invention include hydroxyethyl (meta) acrylate, hydroxypropyl (meta) acrylate and 3-phenoxy-2-hydroxypropyl (meta) acrylate. The (meta) acrylic esters of hydroxyaliphatic amines useful in this invention include (meta) acrylic esters of amines represented by NR1R2R3 wherein R1. R2 and R3 independently represent hydrogen, alkyl groups or hydro-poly (oxyalkylene) groups and at least one of R '. R2 and R3 is a hydroxyalkyl group or a hydro-poly (oxyalkylene) group. Specific examples thereof include (meta) acrylic esters of substituted N, N'-dialkyl dimonoalkanolamines, such as N, N'-dimethylaminoethyl (meta) actable and N, N'-diethylaminoethyl (meth) acrylate; mono- or (meta) acrylic esters of N-alkyl substituted dialkanolamines, such as N-ethyl-N'-hydroxyethylaminoethyl (meth) acrylate and ethyldihydroxyethylamidi (meta) acrylate; (meta) acrylic esters of trialkanolamines, such as triethanolamine (meta) acrylate triethanolamidi (meta) acrylate and triethanolamitri (meta) acrylate; mixtures of alkanolamin (meta) acrylates known generically as oligomers of acrylated amines; and (meta) acrylic esters of hydro-poly (oxyalkylenes), such as the (meta) acrylic ester of (CH3) 2N- (CH2CH20) 2H, the mono- or di (meta) acrylic ester of CH3N [- (CH2CH20) 2H 2, and the mono- or di- (meth) acrylic ester of N [- (CH 2 CH 20) 2 H] 3. Particularly preferred are compounds having the formula (HOR4) 3.xN [R4OCOC (R5) = CH2] X, wherein R4 is an alkylene group having from about 2 to about 12 carbon atoms, or -Re (OR6) m where R6 is -CH2CH2- or -CH2CH (CH3) - and m is an integer from 1 to 6; R5 is hydrogen or a methyl group; and x is an integer from 1 to 3. Examples of (meta) acrylic esters of polyethers include ethylene glycol di (meta) acrylate, diethylene glycol di (meta) acrylate, triethylene glycol di (meta) acrylate, triethylene glycol di (meta) acrylate, 1, 3- butylene glycol di (meta) acrylate and trimethylolpropane tri (meta) acrylate. Examples of (meta) acrylic esters of polyhydric epoxy compounds include di (meta) acrylic esters of biphenol A epichlorohydrin reaction products. The aromatic or aliphatic esters useful as plasticizers in the present invention include dialkyl esters of aromatic carboxylic acids, for example, di (C? -C 2 -alkyl) phthalates, such as dimethyl phthalate, diethyl phthalate, di-n-octyl phthalate, 2-ethylhexylphthalate and octyldecylphthalate; esters of aliphatic monobasic acids, such as butyloleate and glycerol mono-oleate; and esters of aliphatic dibasic acids, such as dibutyladipate, di-2-ethylhexylladipate, dibutylsebacate and di-2-ethylhexylsebacate. Of these plasticizers, the (meta) acrylic esters of alkanolamines or hydro-poly (oxyalkylene) amines represented by the above formula, di (C? -C12-alkyl) phthalates, alkyl esters of (meta) acrylic acid containing hydroxyl and esters ( meta) acrylics of alicyclic alcohols are especially desirable. The plasticizer component is commonly 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. The thermosetting resin composition of the present invention can 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 plasticizing agent are stored in separately and mixed subsequently prior to use. Accordingly, the plasticizing agent used in the present invention can generally be any of the plasticizing agents that are used in one part and two part epoxy resins. However, desirable plasticizing agents for use with the present invention include amine compounds, imidazole compounds, modified amine compounds and modified imidazole compounds. Examples of the amine compounds include dicyanamide; aliphatic polyamines, such as diethylenetriamine, triethylenetetramine and diethylaminpropylamine; aromatic polyamines, such as m-xylene diamine and diamindiphenylamine; alicyclic polyamines, such as isophoronediamine and mannadiamine; and polyamides. Examples of the imidazole compounds include 2-methylimidazole, 2-ethyl-4-methylimidazole and 2-phenylimidazole. Examples of modified amine compounds include epoxy addition polyamines formed by the addition of an amine compound to an epoxy compound, and examples of modified imidazole compounds include imidazole adducts formed by the addition of an imidazole compound to an epoxy compound. Among the mentioned plasticizing agents, latent plasticizing agents used in epoxy resins of a package are particularly preferred. From the point of view of the repair capacity, it is especially desirable to use 5 to 95% by weight of a modified amine in combination with 95 to 5% by weight of dicyandiamine, based on the total weight of the plasticizing agent. The plasticizer itself is commonly used in an amount ranging from about 3 to about 60 parts by weight, per 100 parts by weight of the epoxy resin. Conveniently, the range is from 5 to 40 parts by weight of the resin. It is desirable that the thermosetting resin compositions used in the present invention contain the monofunctional epoxy resin and the aforementioned plasticizer in a combined amount of about 5 to about 40% by weight.

The thermosetting resin compositions according to the present invention are capable of penetrating the space between the circuit board and the semiconductor device. These compositions of the invention also demonstrate reduced viscosity, at least under high temperature conditions, and therefore, can penetrate 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 is 50,000 mPa. s or less, such as 30.00 mPa.s or less, in order to improve its ability to penetrate the space (eg, 100 to 200 μm) between the circuit board and the semiconductor device. The thermosetting resin composition of the present invention may additionally contain other additives, such as antifoaming agents, leveling agents, colorants, pigments and fillers. Additionally, photopolymerization initiators may also be incorporated therein, provided that said initiators do not adversely affect the properties of the composition or the reaction products formed therefrom. The assembly process for carrying out the assembly structure of the present invention is described below. Initially, paste solder is printed on the necessary locations of a circuit board and dries adequately to expel the solvent. Then, a semiconductor device is mounted in accordance with the pattern on the circuit board. This circuit board is passed through a reflow oven to melt the solder and thus weld the semiconductor device. The electrical connection between the semiconductor device and the circuit board is not limited to the use of solder paste, but can be done by welding spheres. Alternatively, this connection can also be made through an electrical conductive adhesive or an anisotropic conductive adhesive. Additionally, solder paste or the like can be applied or formed in either the circuit board or the semiconductor device. To facilitate subsequent repairs, welding, conductive electrical or anisotropic adhesive, should be selected considering its melting point, bond strength and the like. After the semiconductor device is electrically connected to the circuit board in this manner, the resulting structure commonly must be subjected to a continuity test or the like. After passing said test, the semiconductor device with a resin composition. In this way, in the case of a failure, it is easier to remove the semiconductor device before fixing it with the resin composition. Then, using a suitable application means such as a dispenser, a thermosetting resin composition is applied to the periphery of the semiconductor device. When this composition is applied to the semiconductor device, it penetrates the space between the circuit board and the carrier substrate of the semiconductor device by capillary action. Next, the thermosetting resin composition is cured by the application of heat. During the first stage of this heating, the thermosetting resin composition shows a significant reduction in viscosity and therefore an increase in fluidity, so that it penetrates more easily in the space between the circuit board and the semiconductor device. Additionally, by providing the circuit board with suitable vent holes, the thermosetting resin composition can completely penetrate the entire space between the circuit board and the semiconductor device. The amount of thermosetting resin composition applied should be adjusted appropriately to fill the space between the circuit board and the semiconductor device almost completely. When using the thermosetting resin composition mentioned above, it is usually cured by heating to a temperature of 120 ° C to 150 ° C for a period of time of about 5 to 20 minutes. Thus, the present invention can employ relatively low temperature conditions and short-time curing and therefore achieve very good productivity. The mounting structure illustrated in Figure 1 is completed in this manner. When a (meta) acrylic ester is used it is used as a plasticizer in the thermoinduring resin composition and a photopolymerization initiator is added thereto, the thermosetting resin composition can be cured tentatively by exposure to light before heat curing . In the assembly process of the present invention, after the semiconductor device is mounted on the circuit board as mentioned above, the resulting structure is tested with respect to characteristics of the semiconductor device, the connection between the semiconductor device and the control board. circuit, other electrical characteristics, and the state of the seal. In case a fault is found, a repair can be made in the following way. The area around the semiconductor device at the fault site is heated to a temperature from about 190 ° C to about 260 ° C for a period of time ranging from about 10 seconds to about 1 minute. Although no particular limitation is set as to the heating means, local heating is preferred. A relatively simple means such as the application of hot air to the fault site can be employed. As soon as the solder melts and the resin softens to produce a reduction in the bond strength, the semiconductor device is separated. After the semiconductor device 4 is removed as shown in Figure 2, a residue 12 of the cured reaction product of the thermosetting resin composition and a residue 14 of the weld are left in the circuit board 5. The residue of the product Cured reaction of the thermosetting resin composition can be removed, for example, by scraping it after the residue has been softened by heating it to a predetermined temperature, allowing it to expand with solvent, or allowing it to expand with solvent while heating to a temperature default The residue can be easily removed using heating and solvent. For example, the residue may be scraped after it has been smoothed allowing the residual resin to expand with solvent while maintaining 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 that causes the cured reaction products to dilate, thereby reducing the bond strength to such an extent that the cured material can be scraped off the circuit board. Useful solvents include organic solvents, for example, alkyl chlorides such as methylene chloride; glycol ethers, such as eticellulose and butylcellulose; diesters of dibasic acids, such as diethylsuccinate; and N-methylpyrrolidone. Of course, appropriate combinations thereof can also be employed. When a protective circuit resistor has already been applied to the circuit board, the selected solvents must not cause damage to the resistor. Desirable solvents include glycol ethers and N-methylpyrrolidone. The weld residue can be removed, for example, by the use of a welded absorbent braided wire. Finally, on the circuit board that has been cleaned according to the procedure described above, a new semiconductor device is mounted again in the same manner as described above. Thus, the repair of the fault site is completed. When a fault is found in the circuit board, the semiconductor device can be reused by removing the residue 13 from the cured reaction product of the thermosetting resin composition and the residue 15 from the weld left in the bottom of the semiconductor device. the same way as described above. The invention will be further illustrated by the following non-limiting examples. EXAMPLES Example 1 Thermosetting Resin Composition A thermosetting resin composition was prepared by mixing the epoxy resins (i) plasticizing agents (ii) and plasticizer (ii) in the amounts described below, and 0.1 parts by weight of an antifoaming agent. It was observed that the viscosity of the composition formed in this manner was 5,200 Mpa.s. (i) epoxy resins: 85 parts by weight of epoxy resin of biphenol A type, 4 parts by weight of novolac epoxy resin, and 11 parts by weight of a mixture of alkylglycidyl ethers of 12 to 14 carbon atoms. (ii) plasticizing agents: 3 parts by weight of dicyandiamide, and 19 parts by weight of an epoxy adduct of an amine. (iii) plasticizer: 12 parts by weight of an acrylated amine oligomer. Montaie process Using paste solder (PS10-350a-F92C receptacle, manufactured by Harima Chemicals, Inc.) a chip-size package that has a package of 20 square mm, an electrode diameter of 0.5 mm, an electrode pitch of 1.0 mm, and a carrier substrate made of alumina was mounted on an epoxy board reinforced with fiberglass having a circuit formed therein. Subsequently, the thermosetting resin composition was applied to the periphery of the chip size pack by a dispenser, and then cured by heating at 150 ° C for a period of about 5 minutes. During this procedure, the thermosetting resin composition penetrated the space between the semiconductor device and the circuit board before completing curing. Thermal Impact Test Twenty-five samples prepared as described above, were exposed to thermal cycling keeping the sample at a temperature of about -40 ° C for a period of about 30 minutes, followed by an elevation in temperature at room temperature for a period of time of about 30 minutes. time period of about 3 minutes, and then an additional temperature rise to about + 80 ° C for a period of about 30 minutes. After reaching a predetermined number of thermal cycles, the sample was subjected to a continuity test to confirm the electrical connection between the chip size package and the circuit board. The sample was considered acceptable when continuity was confirmed at 1,000 cycles or more, and unacceptable when continuity was lost due to interrupted or similar lines before reaching this number of cycles. Regarding the assembly structure of this example, all 25 samples were acceptable even at more than 1, 000 cycles. Repair Using a hot air generator, the area around the chip size package attached to the circuit board with the thermosetting resin composition was heated as described above by applying hot air at 250 ° C for 1 minute. Then, the chip-size package could be easily removed by inserting a piece of metal between the chip-size package and the fiberglass-reinforced epoxy board, and lifting the chip-size package. While the fiberglass-reinforced epoxy board was maintained at approximately 100 ° C by placing it on a hot plate (or heating it with a far-infrared heater or the like), the resin left on the fiber-reinforced epoxy board was allowed. Glass will be dilated with a solvent such as PS-1 (manufactured by Dai-ichi Kjogyo Seiyaku Co., Ltd.) or 7630 (manufactured by Loctite Corporation), and then removed by scraping with a spatula. The weld left on the fiberglass-reinforced epoxy board was removed using an absorbent braided solder wire. The time required for this repair operation was 3 minutes, which was fast enough from a practical point of view. Paste solder was applied back to the fiberglass reinforced epoxy board from which the chip size package had been removed in the manner described above, and a new chip size package was mounted therein. In this operation, solder paste can be printed on the new chip size package.

In the same manner as described above, the thermosetting resin composition was applied to the periphery of the chip size pack and then cured by heating at 150 ° C for 5 minutes. The electrical connections in the chip size package mounted on the repaired board were securely established. Also in a thermal impact test, this assembly structure exhibited excellent properties similar to those of the unrepaired structure. Examples 2-5 The procedure of Example 1 was repeated, except that the amount of the acrylated amine oligomer used as the plasticizer in Example 1 was altered as shown below. The resulting mounting structures passed a thermal impact test, and their repair time was within 3 minutes. Example 2: 1.2 parts by weight. Example 3: 6.0 parts by weight. Example 4: 21.0 parts by weight. Example 5: 50.0 parts by weight. Comparative Example 1 The procedure of Example 1 was repeated, except that no plasticizer was used. The resulting mounting structure exhibited an acceptable repair capacity, but did not pass a thermal impact test because continuity was lost to less than 1,000 cycles. Comparative Example 2 The procedure of Example 1 was repeated, except that the amount of the acrylated amine oligomer used as the plasticizer in Example 1 was altered to 120 parts by weight. The resulting mounting structure exhibited acceptable repair capability, but did not pass a thermal impact test because continuity was lost to less than 1, 000 cycles. Examples 6-9 The procedure of Example 1 was repeated, except that the amount of the mixture of alkylglycidyl ethers of 12 to 14 carbon atoms used in Example 1 was altered as shown below. The resulting mounting structures passed a thermal impact test, and their repair time was within 3 minutes. Example 6: 0 parts by weight. Example 7: 2.7 parts by weight. Example 8: 5.3 parts by weight. Example 9: 20.0 parts by weight. Comparative Example 3 The procedure of Example 1 was repeated, except that the amount of the alkylglycidyl ether mixture of 12 to 14 carbon atoms used in Example 1 was altered to 40 parts by weight. The resulting mounting structure exhibited an acceptable repair capacity, but did not pass a thermal impact test because continuity was lost to less than 1, 000 cycles. Examples 10-12 The procedure of Example 1 was repeated, except that the acrylated amine oligomer used as the plasticizer in Example 1 was replaced by each of the compounds shown below. The resulting mounting structures passed a thermal impact test, and their repair time was within 3 minutes. Example 10: DOP (dioctylphthalate) Example 11: Isobornylacrylate Example 12: 2-hydroxyethyl (meth) acrylate Example 13 The procedure of Example 1 was repeated except that the epoxy amine adduct used as a plasticizer in Example 1 was replaced by the epoxy imidazole adduct. The resulting mounting structure passed a thermal impact test, and its repair time was within 3 minutes. Comparative Example 4 The procedure of Example 1 was repeated, except that, instead of the thermosetting resin composition used in Example 1, an adhesive (TB3006B, manufactured by Three 20 Pond Co., Ltd.) comprising oligomers of acrylate, acrylate monomers and a photopolymerization initiator and was cured by exposure to light through the space between the semiconductor device and the circuit board and by the application of heat. When this adhesive was used, the semiconductor device was ? -. could easily remove in its semi-cured state. After the adhesive was completely cured, the resulting mounting structure was subjected to a thermal impact test. Its thermal impact properties were unacceptable because continuity was lost to less than 1, 000 cycles. Comparative Example 5 The procedure of Example 1 was repeated except that, instead of the thermosetting resin composition used in Example 1, an epoxy resin sealer (SA-51 -2) was applied.; manufactured by Asahi Kaken Co., Ltd.) in the same manner as in Example 1 and cured by heating at 100 ° for 90 seconds. In a thermal impact test, the resulting mounting structure exhibited the same degree of reliability as Example 1. However, an attempt was made to separate the semi-conductor device by applying heat for repair purposes, but to no avail.

The full scope of the invention is appreciated by the claims.

Claims (19)

1. REINVENT DICATIONS I. A mounting structure for semiconductor devices comprising: a semiconductor device comprising a semiconductor chip mounted on a carrier substrate, and a circuit board to which said semiconductor device is electrically connected, wherein the space between the carrier substrate of such a device semiconductor and said circuit board is sealed with a reaction product of a thermosetting resin composition comprising about 100 parts by weight of an epoxy resin, about 3 to about 60 parts by weight of a plasticizer and about 1 to about 90 parts by weight of a plasticizer.
2. 2. The structure of claim 1, wherein said plasticizer is a member selected from the group consisting of (meta) acrylic esters, aromatic or aliphatic esters and a combination thereof.
3. 3. The structure of claim 1, wherein said plasticizing agent is a member selected from the group consisting of amine compounds, imidazole compounds, modified amine compounds and modified imidazole compounds and combinations thereof.
4. 4. The structure of claim 1, wherein said epoxy resin comprises at least one multifunctional epoxy resin and from 0 to about 30% by weight based on the total weight of said epoxy resin of at least one single-function epoxy resin.
5. The structure of claim 4, wherein the combined amount of such plasticizer and said single-function epoxy resin is from about 5 to about 40% by weight of the total composition.
6. The structure of claim 4, wherein such a single-function epoxy resin has an alkyl group of about 6 to about 28 carbon atoms.
7. The structure of claim 4, wherein such a multifunctional epoxy resin comprises about 10 to about 100% by weight of biphenol type epoxy resin.
8. 8. The structure of claim 1, wherein said plasticizer is an ester. (meta) acrylic of a hydroxyaliphatic amine.
9. The structure of claim 1, wherein the thermosetting resin composition has a viscosity of no greater than about 50,000 mPa.s at a temperature of 25 ° C.
10. 10. A process for semiconductor devices, such process comprises the steps of: electrically connecting a semiconductor device comprising a semiconductor chip mounted on a carrier substrate, to a circuit board; - infiltrating a thermosetting resin composition in the space between the substrate carrier of said semiconductor device and said circuit board, wherein the composition comprises about 100 parts by weight of an epoxy resin, about 3 to about 60 parts by weight of a plasticizing agent and about 1 to about 90 parts by weight of a plasticizer, and curing the thermoinduring resin composition by the application of heat.
11. The process of claim 10, further comprising the steps of: testing the electrical properties of such a circuit board on which said semiconductor device is mounted; if a fault is found in such a test step, remove said semiconductor device at the fault site while heating the vicinity of the fault site; removing the residue of reaction product from the thermosetting resin composition left in said circuit board or in the lower part of such semiconductor device by heating it to a predetermined temperature, impregnating it with an organic solvent, or impregnating it with an organic solvent while heating a predetermined temperature; and removing the residue from the electrically conductive material left in said circuit board or in the lower part of such semiconductor device.
12. 12. The process of claim 10, wherein said plasticizer comprises at least one compound selected from the group consisting of (meta) acrylic esters, aromatic or aliphatic esters and a combination thereof.
13. The process of claim 10, wherein said plasticizing agent comprises at least one compound selected from the group consisting of amine compounds, imidazole compounds, modified amine compounds and modified imidazole compounds and combinations thereof.
14. The process of claim 10, wherein said epoxy resin comprises at least one multifunctional epoxy resin and from 0 to about 30% by weight based on the total weight of said epoxy resin of at least one epoxy resin of said epoxy resin. a single function.
15. The process of claim 14, wherein the combined amount of such a plasticizer and said single-function epoxy resin is from about 5 to about 40% by weight of the total composition.
16. The process of claim 14, wherein such a single-function epoxy resin has an alkyl group of about 6 to about 28 carbon atoms.
17. The process of claim 14, wherein such multifunctional epoxy resin comprises about 10 to about 100% by weight of biphenol type epoxy resin.
18. 18. The structure of claim 10, wherein said plasticizer is an ester. (meta) acrylic of a hydroxyaliphatic amine. The process of claim 10, wherein said thermosetting resin composition has a viscosity no greater than about 50.00 mPa. s at a temperature of 25 ° C. RESU MEN The present invention provides a mounting structure for semiconductor devices that allows a semiconductor device (4), such as chip size / dial grid array, to be securely attached to a circuit board (5) by short-time heat curing (10), which exhibits good productivity, and excellent thermal impact properties (or thermal cycle properties) and which allows the semiconductor device to be easily removed from the circuit board in the event of failure . This invention also provides a process for assembling semiconductor devices.