JP2021061276A - Method for manufacturing semiconductor device - Google Patents

Abstract

To provide a method for manufacturing a semiconductor device, by which good connectability can be achieved even in the case of finally press-fitting a plurality of semiconductor chips included in a preliminary laminate at once.SOLUTION: A method for manufacturing a semiconductor device having a structure in which a plurality of semiconductor chips having through-electrodes and wiring lines are stacked on one another through bumps for electrically connecting the wiring lines of semiconductor chips opposed to each other, and a film-shaped adhesive for semiconductor comprises the steps of: preliminarily press-fitting a plurality of semiconductor chips at a temperature below a melting point of the bumps to obtain a preliminary laminate; and heating and pressurizing the preliminary laminate at a temperature equal to or higher than the melting point of the bumps, ranging from 350 to 400°C, to finally press-fit the plurality of semiconductor chips to each other at once. The film-shaped adhesive for semiconductor contains an epoxy resin, a thermoplastic resin, a hardening agent, a flux agent, and an inorganic filler; the content of the inorganic filler is 20-70 mass% to a total quantity of the film-shaped adhesive for semiconductor.SELECTED DRAWING: None

Description

The present invention relates to a method for manufacturing a semiconductor device.

Conventionally, a wire bonding method using a fine metal wire such as a gold wire has been widely applied to connect a semiconductor chip and a substrate. On the other hand, in order to meet the demands for high functionality, high integration, high speed, etc. for semiconductor devices, a flip chip that directly connects the semiconductor chip and the substrate by forming conductive protrusions called bumps on the semiconductor chip or the substrate. The connection method (FC connection method) is becoming widespread.

The FC connection method includes a method of metal-bonding the connection part using solder, tin, gold, silver, copper, etc., a method of applying ultrasonic vibration to metal-bond the connection part, and mechanical contact by the shrinkage force of the resin. The method of holding the is known. From the viewpoint of reliability of the connecting portion, a method of metal-bonding the connecting portion using solder, tin, gold, silver, copper or the like is common.

For example, regarding the connection between a semiconductor chip and a substrate, a COB (Chip On Board) type connection method that is widely used in BGA (Ball Grid Array), CSP (Chip Size Package), and the like also corresponds to an FC connection method. The FC connection method is also widely used in a COC (Chip On Chip) type connection method in which a connection portion (bump or wiring) is formed on a semiconductor chip to connect the semiconductor chips (for example, a patent). Reference 1).

In addition, for packages that are strongly required to be further miniaturized, thinned, and highly functional, a chip stack type package in which the above-mentioned connection methods are stacked and multi-staged, POP (Patent On Package), TSV (Through-Silicon Via). Etc. have begun to spread widely (see, for example, Patent Document 2). In such a stacking / multi-stage technology, since the semiconductor chips and the like are arranged three-dimensionally, the package can be made smaller than the method of arranging them two-dimensionally. Further, such a stacking / multi-stage technology is attracting attention as a next-generation semiconductor wiring technology because it is effective for improving semiconductor performance, reducing noise, reducing the mounting area, and saving power.

Japanese Unexamined Patent Publication No. 2012-22208 Japanese Unexamined Patent Publication No. 2014-60241

With the trend toward higher functionality and miniaturization of semiconductor devices, it has been proposed to stack and mount a plurality of semiconductor chips. For example, Patent Document 1 discloses a method for manufacturing a semiconductor device in which a plurality of semiconductor chips are temporarily crimped, laminated, and then collectively crimped to reduce the number of times the semiconductor chips are exposed to high temperatures. There is.

Further, for example, Patent Document 2 discloses a configuration and a lamination technique in which a bump and a film-like adhesive for semiconductors covering the bump are provided on one side of the semiconductor chip. In the above laminating technique, a film-like adhesive for semiconductors is laminated in advance on the bump forming surface of the semiconductor chip. When laminating semiconductor chips, first, a plurality of semiconductor chips are sequentially laminated on a substrate or another semiconductor chip while being temporarily crimped to form a multi-stage temporary crimping laminate (temporary laminate). Next, by pressurizing and heating this multi-stage temporary crimping laminate from above, the main crimping step of melting the bumps and curing the film-like adhesive for semiconductors is executed. According to these technologies, a larger number of semiconductor chips can be mounted in a small area, which enables further higher functionality and miniaturization, and shortens the manufacturing time of semiconductor devices, which is expected to improve productivity. ..

Here, in order to realize further high functionality and miniaturization, the number of laminated semiconductor chips may be increased. However, when the laminating technology is used in which the upper surface of the temporary laminated body is heated and pressed to perform main crimping of a plurality of semiconductor chips constituting the temporary laminating body at once, as the number of laminated semiconductor chips increases, the upper layer is increased accordingly. The temperature difference from the lower layer increases. When this temperature difference becomes large, there arises a problem that the semiconductor chip in the lower layer is not sufficiently heated and the bumps are not sufficiently melted. If the bumps do not melt sufficiently, poor connection will occur.

On the other hand, by raising the main crimping temperature in consideration of the temperature difference, it becomes possible to sufficiently heat the semiconductor chip in the lower layer. However, in this case, a higher temperature is applied to the upper layer, which approaches the decomposition temperature of an organic substance such as an epoxy resin contained in the film-like adhesive for semiconductors. Along with this, organic substances are decomposed to generate outgas and voids in the film, which causes a problem that connection failure is likely to occur and insulation reliability is lowered.

Therefore, an object of the present invention is to provide a method for manufacturing a semiconductor device that can obtain good connectivity even when a plurality of semiconductor chips constituting a temporary laminate are collectively crimped.

In order to achieve the above object, the present invention has a plurality of semiconductor chips having through electrodes and wirings via bumps that electrically connect the wirings of the semiconductor chips facing each other and a film-like adhesive for semiconductors. A method for manufacturing a semiconductor device having a laminated structure, wherein the plurality of semiconductor chips are temporarily crimped at a temperature lower than the melting point of the bump to obtain a temporary laminated body, and the temporary laminated body is subjected to the melting point of the bump. Moreover, the step of heating and pressurizing at a temperature of 350 to 400 ° C. and finally crimping the plurality of semiconductor chips together is provided, and the semiconductor film-like adhesive is an epoxy resin, a thermoplastic resin, or a curing agent. , A flux agent, and an inorganic filler, and the content of the inorganic filler is 20 to 70% by mass based on the total amount of the film-like adhesive for semiconductors.

According to the above manufacturing method, when a plurality of semiconductor chips constituting a temporary laminate are collectively subjected to main crimping, the main crimping is performed at a specific temperature using the above-mentioned film-like adhesive for semiconductors having a specific composition. As a result, the bumps of the semiconductor chip in the lower layer can be sufficiently melted, the generation of outgas and voids can be sufficiently suppressed, and a semiconductor device having good connectivity can be manufactured.

In the above-mentioned production method, the weight average molecular weight of the above-mentioned thermoplastic resin may be 10,000 or more.

Further, in the above-mentioned manufacturing method, the minimum melt viscosity of the above-mentioned film-like adhesive for semiconductors may be 5000 Pa · s or less.

Further, in the above manufacturing method, the number of the plurality of semiconductor chips may be 4 to 16.

According to the present invention, it is possible to provide a method for manufacturing a semiconductor device that can obtain good connectivity even when a plurality of semiconductor chips constituting a temporary laminate are collectively crimped.

It is a schematic cross-sectional view which shows one Embodiment of the manufacturing method of a semiconductor device. It is a schematic cross-sectional view which shows one Embodiment of the manufacturing method of a semiconductor device. It is a schematic cross-sectional view which shows one Embodiment of the manufacturing method of a semiconductor device. It is a schematic cross-sectional view which shows one Embodiment of the manufacturing method of a semiconductor device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings in some cases. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted. In addition, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown.

In the present specification, the numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value of the numerical range of one step can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of another step. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. "A or B" may include either A or B, or both. Unless otherwise specified, the materials exemplified in the present specification may be used alone or in combination of two or more.

In the method for manufacturing a semiconductor device according to the present embodiment, a plurality of semiconductor chips having a through electrode and wiring are electrically connected to each other by wiring of the semiconductor chips facing each other via a bump and a semiconductor film-like adhesive. A method for manufacturing a semiconductor device having a laminated structure, wherein the plurality of semiconductor chips are temporarily crimped at a temperature lower than the melting point of the bump to obtain a temporary laminated body, and the temporary laminated body is subjected to the melting point of the bump. Moreover, the step of heating and pressurizing at a temperature of 350 to 400 ° C. and finally crimping the plurality of semiconductor chips together is provided. The production method contains an epoxy resin, a thermoplastic resin, a curing agent, a flux agent, and an inorganic filler, and the content of the inorganic filler is 20 to 70 based on the total amount of the film-like adhesive for semiconductors. A film-like adhesive for semiconductors, which is by mass%, is used.

<Film-like adhesive for semiconductors>
The film-like adhesive for semiconductors contains an epoxy resin, a thermoplastic resin, a curing agent, a flux agent, and an inorganic filler. Hereinafter, each component will be described.

(Epoxy resin)
The epoxy resin is not particularly limited as long as it has an epoxy group in the molecule, but an epoxy resin having two or more epoxy groups in the molecule can be preferably used. Examples of such epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, and biphenyl type epoxy resin. Triphenol methane type epoxy resin, dicyclopentadiene type epoxy resin; these polyfunctional epoxy resins can be mentioned. The epoxy resin may be used alone or in combination of two or more. Of these, the epoxy resin preferably contains a bisphenol type epoxy resin or a triphenol methane type epoxy resin.

The epoxy resin is preferably one that can suppress decomposition to generate volatile components when connected at a high temperature. Therefore, it is preferable to use an epoxy resin having a mass reduction rate of 20% by mass or less under heating conditions at the time of connection.

The content of the epoxy resin is preferably 5 to 75% by mass, more preferably 10 to 55% by mass, and further preferably 20 to 50% by mass, based on the total amount of the film-like adhesive for semiconductors. When the content of the epoxy resin is in such a range, it tends to be more excellent in curability and more excellent in adhesiveness.

(Thermoplastic resin)
The thermoplastic resin is not particularly limited, but from the viewpoint of obtaining excellent heat resistance, film formability and connection reliability, a phenoxy resin, a polyimide resin, a polyamide resin, a polycarbodiimide resin, a cyanate ester resin, an acrylic resin, and a polyester resin. , Polyester resin, polyether sulfone resin, polyetherimide resin, polyvinyl acetal resin, urethane resin and acrylic rubber preferably contain at least one selected from the group. From the viewpoint of being more excellent in heat resistance and film forming property, the thermoplastic resin may contain at least one selected from the group consisting of phenoxy resin, polyimide resin, acrylic rubber, acrylic resin, cyanate ester resin and polycarbodiimide resin. It is preferable to include at least one selected from the group consisting of phenoxy resin, polyimide resin, acrylic rubber and acrylic resin.

The weight average molecular weight of the thermoplastic resin is preferably 10,000 or more, more preferably 20,000 or more, and even more preferably 30,000 or more. When the weight average molecular weight of the thermoplastic resin is 10,000 or more, the heat resistance and film forming property of the film-like adhesive for semiconductors tend to be further improved. The weight average molecular weight of the thermoplastic resin is preferably 1,000,000 or less, more preferably 500,000 or less. When the weight average molecular weight of the thermoplastic resin is 1,000,000 or less, the effect of high heat resistance tends to be obtained.

The weight average molecular weight means a value measured by GPC (Gel Permeation Chromatography) and converted using a calibration curve using standard polystyrene. An example of the measurement conditions for the weight average molecular weight is shown below.

Device name: HCL-8320GPC, UV-8320 (manufactured by Tosoh Corporation), or HPLC-8020 (manufactured by Tosoh Corporation)
Column: TSKgel superMultipore HZ-M × 2, or 2 pieces of GMHXL + 1 piece of G-2000XL
Detector: RI or UV detector Column temperature: 25-40 ° C
Eluent: A solvent in which the measurement target dissolves can be selected. Examples of the solvent include THF (tetrahydrofuran), DMF (N, N-dimethylformamide), DMA (N, N-dimethylacetamide), NMP (N-methyl-2-pyrrolidone), toluene and the like. When selecting a solvent having polarity, the concentration of phosphoric acid is 0.05 to 0.1 mol / L (usually 0.06 mol / L), and the concentration of LiBr is 0.5 to 1.0 mol / L (usually 0.06 mol / L). Usually, it may be adjusted to 0.63 mol / L).
Flow velocity: 0.30 to 1.5 mL / min Standard substance: Polystyrene

The mass ratio of the epoxy resin content to the thermoplastic resin content (epoxy resin content / thermoplastic resin content) based on the total amount of the film-like adhesive for semiconductors is preferably 0.01. ~ 20, more preferably 0.05 to 15, still more preferably 0.1 to 10.

(Hardener)
The curing agent is not particularly limited, and examples thereof include an imidazole-based curing agent, a phenol resin-based curing agent, an acid anhydride-based curing agent, an amine-based curing agent, and a phosphine-based curing agent. Among these, the curing agent preferably contains an imidazole-based curing agent from the viewpoint of exhibiting good flux performance and being superior in storage stability and heat resistance of the cured product of the film-like adhesive for semiconductors.

Examples of the imidazole-based curing agent include 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole. , 1-Cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimerite, 1-cyanoethyl-2-phenylimidazolium trimerite, 2,4-diamino-6- [2'-methylimidazolyl -(1')]-Ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [ 2'-Ethyl-4'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine Isocyanuric acid adduct, isocyanuric acid adduct of 2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, adduct of epoxy resin and imidazoles And so on. These may be used individually by 1 type or in combination of 2 or more type.

Among these, from the viewpoint of being superior in curability, storage stability and connection reliability, the imidazole-based curing agents are 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, and 1-cyanoethyl-2-. Undecylimidazole trimerite, 1-cyanoethyl-2-phenylimidazolium trimerite, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4 -Diamino-6- [2'-ethyl-4'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]- Selected from the group from the isocyanuric acid adduct of ethyl-s-triazine, the isocyanuric acid adduct of 2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. It is preferable that it is at least one type. Further, these may be microencapsulated and used as a latent curing agent.

The content of the curing agent is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin. When the content of the curing agent is 0.1 part by mass or more with respect to 100 parts by mass of the epoxy resin, the curability tends to be further improved, and when it is 20 parts by mass or less, a metal bond is formed. The film-like adhesive for semiconductors does not cure before the bonding, and connection failure tends to be less likely to occur.

(Flux agent)
The flux agent can be used without particular limitation as long as it is a compound having a carboxyl group, but a dicarboxylic acid (a compound having two carboxyl groups) is preferable. Compared with monocarboxylic acid (a compound having one carboxyl group), dicarboxylic acid is less likely to volatilize even at a high temperature at the time of connection, and tends to further suppress the generation of voids. Further, when a dicarboxylic acid is used, it is possible to further suppress an increase in the viscosity of the semiconductor film-like adhesive during storage, connection work, etc., as compared with the case where a compound having three or more carboxyl groups is used. , There is a tendency that the connectivity of semiconductor devices can be further improved.

The flux agent may be, for example, a dicarboxylic acid having a linear or branched alkylene group. Examples of such dicarboxylic acids include succinic acid (melting point: 184 ° C.), glutaric acid (melting point: 95 to 98 ° C.), adipic acid (melting point: 152 ° C.), pimelic acid (melting point: 103 to 105 ° C.), and the like. Suberic acid (melting point: 141-144 ° C), adipic acid (melting point: 109 ° C), sebacic acid (melting point: 133-137 ° C), undecanedioic acid (melting point: 28-31 ° C), dodecanedioic acid (melting point: 127 ° C) ~ 129 ° C.) or the like; a dicarboxylic acid having a linear alkylene group; a branched dicarboxylic acid in which the hydrogen atom at the 2- or 3-position of the dicarboxylic acid having a linear alkylene group is substituted with one or more alkyl groups. Examples thereof include dicarboxylic acids having an alkylene group. Examples of the dicarboxylic acid having a branched alkylene group include 2-methylglutaric acid (melting point: 80 to 82 ° C.). The flux agent preferably contains 2-methylglutaric acid or glutaric acid.

The melting point of the flux agent is preferably 150 ° C. or lower, more preferably 140 ° C. or lower, and even more preferably 130 ° C. or lower. Such a flux agent tends to sufficiently exhibit flux performance before a curing reaction between the epoxy resin and the curing agent occurs. Therefore, by using a film-like adhesive for semiconductors containing such a flux agent, it is possible to manufacture a semiconductor device having further excellent connection reliability. The flux agent is preferably solid at room temperature (25 ° C.), and the melting point of the flux agent is preferably 25 ° C. or higher, more preferably 50 ° C. or higher.

The content of the flux agent may be, for example, 0.5 to 10% by mass based on the total amount of the film-like adhesive for semiconductors.

(Inorganic filler)
By containing an inorganic filler, the semiconductor film-like adhesive tends to further suppress the generation of voids at the time of connection and further reduce the hygroscopicity of the cured product of the semiconductor film-like adhesive.

The inorganic filler is preferably an insulating substance from the viewpoint of excellent insulation reliability (particularly HAST resistance). Examples of such an inorganic filler include glass, silica, alumina, titanium oxide, carbon black, mica, boron nitride and the like. These may be used individually by 1 type or in combination of 2 or more type. Among these, the inorganic filler is preferably at least one selected from the group consisting of silica, alumina, titanium oxide, and boron nitride, and more preferably at least one selected from the group consisting of silica, alumina, and boron nitride. is there. These shapes and particle sizes are not particularly limited. Further, the inorganic filler may be surface-treated. As the inorganic filler, two or more kinds of inorganic fillers having different shapes, particle sizes or surface treatments may be used in combination. When inorganic fillers having different particle sizes are used in combination, there is an advantage that the fluidity can be easily controlled.

The content of the inorganic filler is 20 to 70% by mass, preferably 25 to 65% by mass, and more preferably 30 to 60% by mass, based on the total amount of the film-like adhesive for semiconductors. When the content of the inorganic filler is in such a range, the generation of outgas and voids is suppressed even when a plurality of semiconductor chips constituting the temporary laminate are collectively crimped at a temperature of 350 to 400 ° C. It is possible to obtain a semiconductor device having good connectivity. If the content of the inorganic filler is less than 20% by mass, the generation of outgas and voids cannot be sufficiently suppressed, and if it exceeds 70% by mass, the resin does not easily flow during the main crimping, resulting in poor connection. Wake up.

(Resin filler)
The film-like adhesive for semiconductors may further contain a resin filler. By containing the resin filler, it is possible to control the physical characteristics of the cured product of the film-like adhesive for semiconductors, and it is possible to suppress warpage when a plurality of semiconductor chips are connected. Further, by containing the resin filler, the viscosity of the film-like adhesive for semiconductors and the physical characteristics of the cured product can be controlled, and the generation of voids and the hygroscopicity when a plurality of semiconductor chips are connected can be suppressed. it can.

Examples of the resin filler include fillers made of resins such as polyurethane, polyimide, silicone, methyl methacrylate resin and methyl methacrylate-butadiene-styrene copolymer resin (MBS). The resin filler may be particles having a core-shell type structure. Examples of the core-shell type structure include a structure having a core layer (core material) and a shell layer (surface layer) provided so as to cover the core layer. The core layer and the shell layer may have the same composition or different compositions.

The content of the resin filler is preferably 1 to 30% by mass, more preferably 2 to 30% by mass, and further preferably 3 to 15% by mass, based on the total amount of the film-like adhesive for semiconductors.

(Other ingredients)
The film-like adhesive for semiconductors may further contain a curing accelerator, a silane coupling agent, a titanium coupling agent, an antioxidant, a leveling agent, an ion trapping agent, and the like as other components. The content of the other components can be appropriately adjusted so that each component exerts its effect, and may be, for example, 0.1 to 20% by mass based on the total amount of the film-like adhesive for semiconductors.

As the film-like adhesive for semiconductors, for example, a resin composition varnish obtained by adding an organic solvent to a resin composition containing each of the above-mentioned components as necessary, stirring and mixing, kneading, etc. is used. Can be formed. In this case, for example, the resin composition varnish is applied onto the release-treated base film using a knife coater, a roll coater, an applicator, or the like, and the applied resin composition varnish is heated to heat an organic solvent. By removing the above, a film-like adhesive for semiconductors can be formed on the base film.

The organic solvent used for preparing the resin composition varnish is not particularly limited as long as it has the property of uniformly dissolving or dispersing each component, and is, for example, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone. , Dimethyl sulfoxide, diethylene glycol dimethyl ether, toluene, benzene, xylene, methyl ethyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone, ethyl acetate and the like. These organic solvents may be used alone or in combination of two or more. Among these, the organic solvent preferably contains methyl ethyl ketone.

Stirring and mixing, kneading and the like in the preparation of the resin composition varnish can be carried out by using, for example, a stirrer, a raft machine, three rolls, a ball mill, a bead mill, a homodisper or the like.

The base film is not particularly limited as long as it has heat resistance that can withstand the heating conditions when the organic solvent is dried. Examples of the base film include a polyolefin film such as a polypropylene film and a polymethylpentene film, a polyester film such as a polyethylene terephthalate film and a polyethylene naphthalate film, a polyimide film, and a polyetherimide film. The base film may be a single-layer film of one type alone or a multilayer film in which two or more types are combined.

The thickness of the film-like adhesive for semiconductors can be adjusted based on, for example, the height of the bumps before connection, and is preferably 0.5 to 1.5 times based on the height of the bumps before connection. , More preferably 0.6 to 1.3 times, still more preferably 0.7 to 1.2 times. When the thickness of the film-like adhesive for semiconductors is 0.5 times or more the height of the bumps, the generation of voids due to unfilling of the film-like adhesive for semiconductors can be sufficiently suppressed, and the connection reliability can be improved. It can be further improved. Further, when the thickness of the semiconductor film-like adhesive is 1.5 times or less the height of the bump, the amount of the semiconductor film-like adhesive extruded from the chip connection region at the time of connection can be sufficiently suppressed. Furthermore, it is possible to sufficiently prevent the film-like adhesive for semiconductors from adhering to unnecessary parts. Therefore, it is not necessary to remove the film-like adhesive for semiconductors from the bumps, it is possible to prevent poor continuity and reduce damage against weakening of bumps (minimization of bump diameter) due to narrowing the pitch and increasing the number of pins. it can. Since the bump height is generally 5 to 100 μm, the thickness of the semiconductor film-like adhesive is preferably 2.5 to 150 μm, more preferably 3.5 to 120 μm.

The drying conditions for volatilizing the organic solvent from the resin composition varnish applied to the base film are not particularly limited as long as the organic solvent volatilizes sufficiently, but the temperature is 50 to 200 ° C. for 0.1 to 90 minutes. It is preferably heating. The organic solvent is preferably removed up to 1.5% by mass or less based on the total amount of the film-like adhesive for semiconductors.

The semiconductor film-like adhesive may be formed directly on the semiconductor chip. Specifically, for example, the resin composition varnish may be spin-coated directly on the semiconductor chip, and then the organic solvent may be removed to form the semiconductor film-like adhesive directly on the semiconductor chip.

The minimum melt viscosity of the film-like adhesive for semiconductors may be 5000 Pa · s or less, 100 to 4000 Pa · s, or 500 to 3000 Pa · s. When the minimum melt viscosity is 5000 Pa · s or less, the resin tends to flow easily and the connectivity tends to be excellent, and when it is 100 Pa · s or more, bleeding of the resin (resin that protrudes to the outside of the chip during main crimping) is suppressed. There is a tendency to be able to do it. The minimum melt viscosity of a film-like adhesive for semiconductors is defined as the minimum value of the viscosity measurement value measured by raising the temperature from 35 ° C. to 200 ° C.

<Manufacturing method of semiconductor devices>
As shown in FIGS. 1 to 4, a method of manufacturing the semiconductor device of the present embodiment will be described in a case where a plurality of semiconductor chips 10 are mounted on the substrate 50 to manufacture the semiconductor device 500. Here, the semiconductor device 500 shown in FIG. 4 is a semiconductor device using the TSV technology. In the semiconductor device 500 shown in FIG. 4, the wiring 15 formed on the substrate 50 is connected to the wiring 15 of the semiconductor chip 10 via the connection bump 30, so that the semiconductor chip 10 and the substrate 50 are flip-chip connected. ing. The gap between the semiconductor chip 10 and the substrate 50 is filled with the adhesive material 45 without any gap. The adhesive material 45 is a cured product of the semiconductor film-like adhesive 40. The connection bump 30 is sealed by the adhesive material 45 and is shielded from the external environment. The semiconductor chip 10 is repeatedly laminated on the surface of the semiconductor chip 10 on the side opposite to the substrate 50 via the wiring 15, the connection bump 30, and the adhesive material 45. The wiring 15 on the pattern surface on the front and back of the semiconductor chip 10 is connected to each other by a through electrode 34 filled in a hole penetrating the inside of the semiconductor chip 10. As the material of the through electrode 34, copper, aluminum, or the like can be used.

In the method for manufacturing a semiconductor device of the present embodiment, first, the semiconductor film-like adhesive 40 is attached onto the substrate 50 or the semiconductor chip 10. The semiconductor film-like adhesive 40 can be attached by a heat press, roll laminating, vacuum laminating, or the like. Further, as described above, the resin composition varnish is spin-coated directly on the substrate 50 or the semiconductor chip 10, and then the organic solvent is removed to directly spin-coat the semiconductor film-like adhesive 40 on the substrate 50 or the semiconductor chip 10. May be formed. The supply area and thickness of the semiconductor film-like adhesive 40 are appropriately set according to the size of the semiconductor chip 10 or the substrate 50 and the height of the connection bump 30. The semiconductor film-like adhesive 40 may be attached to the semiconductor chip 10, and the semiconductor film-like adhesive 40 is attached by dicing the semiconductor wafer and then dicing the semiconductor chip 10 into individual pieces. The semiconductor chip 10 may be manufactured.

After the semiconductor film-like adhesive 40 is attached to the substrate 50 or the semiconductor chip 10, the connection bump (solder bump or the like) 30 of the semiconductor chip 10 and the wiring (copper wiring or the like) 15 of the substrate 50 are attached to a flip chip bonder or the like. Align using a connector. Subsequently, as shown in FIG. 1, the semiconductor chip 10 and the substrate 50 are temporarily crimped while being heated at a temperature lower than the melting point of the connection bump 30, to obtain the first temporary laminate 100.

Next, as shown in FIG. 2, the semiconductor chip 10 to which the semiconductor film-like adhesive 40 is attached is further temporarily crimped onto the semiconductor chip 10 of the first temporary laminate 100, and the second temporary laminate 200 is formed. obtain. When obtaining the second temporary laminate 200, the semiconductor film-like adhesive 40 may be attached onto the semiconductor chip 10 of the first temporary laminate 100.

Subsequently, as shown in FIG. 3, the semiconductor chip 10 to which the semiconductor film-like adhesive 40 is attached is further temporarily crimped onto the semiconductor chip 10 of the second temporary laminate 200, and the third temporary laminate 300 is further temporarily crimped. To get. As shown in FIG. 3, the semiconductor chip 10 arranged at the uppermost portion does not have to have the wiring 15 on the surface opposite to the connection bump 30. When obtaining the third temporary laminate 300, the semiconductor film-like adhesive 40 may be attached onto the semiconductor chip 10 of the second temporary laminate 200.

After that, the third temporary laminate 300 is heated and pressed at a temperature equal to or higher than the melting point of the connection bump 30 and at a temperature of 350 to 400 ° C., and the substrate 50 and the plurality of semiconductor chips 10 are collectively crimped. Further, the semiconductor film-like adhesive 40 is cured by the above-mentioned main crimping to form the adhesive material 45, and the adhesive material 45 is used between the semiconductor chip 10 and the substrate 50 and between the plurality of semiconductor chips 10. The voids are sealed and filled. From the above, the semiconductor device 500 can be manufactured.

In the above manufacturing method, the temperature at the time of temporary crimping may be, for example, 50 to 150 ° C., 60 to 130 ° C., or 70 to 100 ° C. If the temperature exceeds 150 ° C., the curing reaction of the film proceeds and the fluidity tends to decrease, so that the connectivity tends to decrease. If the temperature is less than 50 ° C., the film does not soften and the fluidity decreases. As a result, connectivity tends to decrease.

The pressure at the time of temporary crimping may be, for example, 0.125 to 6.25 MPa, 0.375 to 3.75 MPa, or 0.625 to 2.5 MPa. If the pressure exceeds 6.25 MPa, the pressure is high and the semiconductor chip may be destroyed. If the pressure is less than 0.125 MPa, the pressure is low and the crimping tends to be insufficient.

The crimping time at the time of temporary crimping may be, for example, 0.5 to 30 seconds, 1 to 20 seconds, or 2 to 10 seconds. If the crimping time exceeds 30 seconds, it tends to be inferior in productivity because it takes too much time for one crimping, and if it is less than 0.5 seconds, it tends to be difficult to sufficiently crimp.

In the above manufacturing method, the temperature at the time of the main crimping is set to be equal to or higher than the melting point of the connecting bump 30 and 350 to 400 ° C. When the temperature is 350 ° C. or higher, heat is sufficiently easily transferred to the semiconductor chip located at the lowermost stage among the plurality of semiconductor chips, and when the temperature is 400 ° C. or lower, outgas is generated at the semiconductor chip located at the uppermost stage. It is suppressed.

The pressure at the time of the main crimping may be, for example, 0.125 to 6.25 MPa, 0.375 to 3.75 MPa, or 0.625 to 2.5 MPa. If the pressure exceeds 6.25 MPa, the pressure is high and the semiconductor chip may be destroyed. If the pressure is less than 0.125 MPa, the pressure is low and the crimping tends to be insufficient.

The crimping time at the time of the main crimping may be, for example, 0.5 to 30 seconds, 1 to 20 seconds, or 2 to 10 seconds. If the crimping time exceeds 30 seconds, heat tends to be applied too much and outgas is likely to be generated, and if it is less than 0.5 seconds, heat is generated to the semiconductor chip located at the lowermost stage among the plurality of semiconductor chips. It is not sufficiently transmitted and tends to cause poor connection.

In the method for manufacturing a semiconductor device of the present embodiment, after the main crimping, heat treatment may be performed in an oven or the like to further improve connection reliability and insulation reliability. The heating temperature is preferably a temperature at which the curing of the semiconductor film-like adhesive 40 proceeds, and more preferably a temperature at which the curing is completely completed. The heating temperature and heating time are set as appropriate.

The semiconductor chip 10 is not particularly limited, and an elemental semiconductor composed of elements of the same type such as silicon and germanium, and a compound semiconductor such as gallium arsenide and indium phosphide can be used.

The substrate 50 is not particularly limited as long as it is a circuit board, and unnecessary parts of the metal film are etched on the surface of an insulating substrate containing glass epoxy, polyimide, polyester, ceramic, epoxy, bismaleimide triazine and the like as main components. A circuit board having a wiring (wiring pattern) 15 formed by removing the circuit board, a circuit board in which the wiring 15 is formed by metal plating or the like on the surface of the insulating substrate, and a conductive material printed on the surface of the insulating substrate for wiring. A circuit board on which 15 is formed can be used.

The connection portions of the wiring 15 and the connection bump 30 are mainly composed of gold, silver, copper, and solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper, tin-silver-copper). ), Nickel, tin, lead and the like, and may contain a plurality of metals.

Among the above metals, gold, silver and copper are preferable, and silver and copper are more preferable, from the viewpoint of forming a package having excellent electrical and thermal conductivity of the connection portion. From the viewpoint of providing a package with reduced cost, silver, copper and solder are preferable, copper and solder are more preferable, and solder is further preferable because of its low cost. If an oxide film is formed on the surface of a metal at room temperature, the productivity may decrease and the cost may increase. Therefore, from the viewpoint of suppressing the formation of the oxide film, gold, silver, copper and solder are preferable, and gold and silver are preferable. , Solder is more preferable, and gold and silver are more preferable.

The surfaces of the wiring 15 and the connection bump 30 are mainly composed of gold, silver, copper, solder (main components are, for example, tin-silver, tin-lead, tin-bismuth, tin-copper), tin, nickel and the like. The metal layer as a component may be formed by, for example, plating. This metal layer may be composed of only a single component or may be composed of a plurality of components. Further, the metal layer may have a structure in which a single layer or a plurality of metal layers are laminated.

The semiconductor device 500 shown in FIG. 4 has a structure in which three semiconductor chips 10 are laminated on a substrate 50, but the number of the semiconductor chips 10 to be laminated is not particularly limited. The number of semiconductor chips 10 to be laminated may be 4 to 15, 6 to 12, or 8 to 10. Even when a large number of semiconductor chips 10 are collectively crimped as described above, a semiconductor device having good connectivity can be obtained according to the method for manufacturing a semiconductor device of the present embodiment.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

[Examples 1 to 4 and Comparative Examples 1 to 4]
<Manufacturing of film-like adhesives for semiconductors>
Epoxy resin, curing agent, flux agent, inorganic filler and resin filler of the type and content (unit: parts by mass) shown in Table 1 were added to the ball mill container, and cyclohexanone was further added so that the solid content was 50% by mass. .. Beads having a diameter of 1.0 mm were added to the ball mill container by the same mass as the solid content, and the mixture was stirred for 30 minutes using a ball mill device (manufactured by Lecce Co., Ltd., trade name "planetary ball mill PM400"). Then, a thermoplastic resin of the type and content (unit: parts by mass) shown in Table 1 was added to the ball mill container, and the mixture was stirred again in the ball mill for 30 minutes. The beads used for stirring were removed by filtration to obtain a resin composition varnish.

The obtained resin composition varnish is coated on a base film (manufactured by Teijin DuPont Film Co., Ltd., trade name "Purex A55") with a small precision coating device (manufactured by Yasui Seiki Co., Ltd.) to clean it. It was dried in an oven (manufactured by Espec Co., Ltd.) (100 ° C./5 min) to obtain a film-like adhesive for semiconductors (thickness: 20 μm) of Examples and Comparative Examples.

The materials used in the examples and comparative examples are as follows.
(Epoxy resin)
EP1032: Triphenol methane skeleton-containing polyfunctional solid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name "EP1032H60"
YL983U: Bisphenol F type liquid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name "YL983U"
YX-7110: Long-chain bisphenol F type liquid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name "YX-7110"
(Thermoplastic resin)
FX-293: Fluorene skeleton-containing phenoxy resin (manufactured by Toto Kasei Co., Ltd., trade name "FX-293", weight average molecular weight 40,000
(Hardener)
2P4MHZ: 2-Phenyl-4-methyl-5-hydroxymethylimidazole (manufactured by Shikoku Chemicals Corporation, trade name "2P4MHZ-PW")
(Flux agent)
Glutaric acid (manufactured by Tokyo Kasei Co., Ltd., melting point approx. 98 ° C)
(Inorganic filler)
SE2030: Silica filler (manufactured by Admatex Co., Ltd., trade name "SE2030", average particle size 0.5 μm)
Epoxy surface-treated nanosilica filler (manufactured by Admatex Co., Ltd., trade name "50 nm SE-AH1", average particle size: about 50 nm, hereinafter referred to as "SE nanosilica")
(Resin filler)
EXL-2655: Organic filler (core-shell type organic fine particles) (manufactured by Roam and Hearth Japan Co., Ltd., trade name "EXL-2655", core part: butadiene / styrene copolymer polymer, shell part: PMMA / styrene copolymer polymer)

<Manufacturing of semiconductor devices>
The produced film-like adhesive for semiconductors is cut out to a predetermined size (length 10 mm × width 8 mm × thickness 18 μm), and a semiconductor chip (A) with solder bumps (length 10 mm × width 8 mm, thickness 50 μm, solder bump height 20 μm). (Solder height 15 μm, Copper pillar height 5 μm), Number of bumps 1914, Wire with height 5 μm on the opposite side of the surface with solder bumps, Melting point of solder bumps about 200 ° C) Attached to the surface with solder bumps, separate Temporary crimping temperature 80 ° C., crimping time 2 seconds, crimping pressure with a mounting device (manufactured by Panasonic Corporation, trade name "FCB3") on a semiconductor chip (length 13 mm x width 13 mm x thickness 100 μm, wiring height 5 μm) Temporarily crimped under mounting conditions of 60 N (0.75 MPa). Further, on the wiring surface (the surface opposite to the surface with the solder bumps) of the semiconductor chip (A) with the solder bumps, a semiconductor chip (A) with the same solder bumps as described above is further placed on the surface with the solder bumps for a semiconductor film. The soldering agent was attached and temporarily crimped by the same method as described above. After temporarily crimping seven semiconductor chips (A) with solder bumps, the semiconductor chips (B) with solder bumps (length 10 mm x width 8 mm x thickness 50 μm, solder bump height 20 μm (solder height 15 μm, copper pillars) (Height 5 μm), the number of bumps 1914, and no wiring on the opposite surface to the surface with solder bumps) were temporarily crimped to prepare a temporary laminate. Next, the obtained temporary laminate is finally crimped with the above mounting device under the mounting conditions of a crimping time of 10 seconds and a crimping pressure of 100 N (1.25 MPa) to prepare a semiconductor device (number of laminated semiconductor chips: 9). did. The crimping temperature at the time of the main crimping was the temperature shown in Table 1.

<Measurement of minimum melt viscosity>
The minimum melt viscosity of the produced film-like adhesive for semiconductors was measured by the following method. The produced semiconductor film was punched into a 10 mm square to prepare a sample for evaluation. The viscosity of this evaluation sample was measured using a rotary rheometer (manufactured by TA Instruments, trade name: ARES-G2). Among the measured values obtained from the measurement, the lowest value was defined as the minimum melt viscosity. The results are shown in Table 1.
(Measurement condition)
Measurement mode: Dynamic Temperature Ramp.
Temperature rise rate: 10 ° C / min
Frequency: 10Hz
Measurement temperature: 35-200 ° C

<Evaluation of connectivity>
The initial continuity after mounting was evaluated by measuring the connection resistance value of the manufactured semiconductor device using a multimeter (manufactured by ADC Co., Ltd., trade name "R6781E"). Those for which the connection resistance value could be obtained were evaluated as "OK" as good connectivity, and those for which the connection resistance value could not be obtained and were opened due to poor connection (when the resistance value was not displayed) were evaluated as "NG". The results are shown in Table 1.

As is clear from the results shown in Table 1, the content of the inorganic filler in the film-like adhesive for semiconductors is within the range of 20 to 70% by mass, and the crimping temperature during the main crimping is 350 to 400 ° C. It was confirmed that within the range, it is possible to manufacture a semiconductor device in which a large number of semiconductor chips having good connectivity are laminated.

10 ... Semiconductor chip, 15 ... Wiring (connection part), 30 ... Connection bump, 34 ... Through electrode, 40 ... Semiconductor film-like adhesive, 45 ... Adhesive material, 50 ... Substrate, 500 ... Semiconductor device.

Claims (4)

A method for manufacturing a semiconductor device having a structure in which a plurality of semiconductor chips having through electrodes and wiring are laminated via a bump for electrically connecting the wirings of the opposing semiconductor chips and a film-like adhesive for semiconductors. hand,
A step of temporarily crimping the plurality of semiconductor chips at a temperature lower than the melting point of the bump to obtain a temporary laminate.
A step of heating and pressurizing the temporary laminate at a temperature equal to or higher than the melting point of the bump and at a temperature of 350 to 400 ° C.
With
The semiconductor film-like adhesive contains an epoxy resin, a thermoplastic resin, a curing agent, a flux agent, and an inorganic filler.
A method for manufacturing a semiconductor device, wherein the content of the inorganic filler is 20 to 70% by mass based on the total amount of the film-like adhesive for semiconductors. The method for manufacturing a semiconductor device according to claim 1, wherein the thermoplastic resin has a weight average molecular weight of 10,000 or more. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein the minimum melt viscosity of the film-like adhesive for semiconductors is 5000 Pa · s or less. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, wherein the number of the plurality of semiconductor chips is 4 to 16.

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