JP5011972B2 - Liquid resin composition, semiconductor wafer with adhesive layer, semiconductor element with adhesive layer, and semiconductor package - Google Patents

Description

  The present invention relates to a liquid resin composition, and further relates to a semiconductor wafer with an adhesive layer, a semiconductor element with an adhesive layer, and a semiconductor package using an adhesive composed of the liquid resin composition.

In recent years, mobile phones, personal digital assistants, DVCs (digital video cameras), etc., have advanced significantly in function, size, and weight, and there is a strong demand for higher functionality, size, and weight reduction of semiconductor packages. ing. Therefore, a plurality of semiconductor elements having different functions or a plurality of semiconductor elements having the same function are mounted on a single package to enhance the function of the semiconductor package, and the size of the semiconductor element and the size of the package are reduced in size and weight. Attempts have been made to get as close as possible. For this reason, the thickness of the semiconductor element is further reduced, and the distance of the wire bond pad between the semiconductor element and a support such as a metal or organic substrate is becoming increasingly shorter.
In the conventional die attach process in the semiconductor assembly process, a liquid die attach material is applied to the support, and the semiconductor element is bonded to the support by mounting after heating the semiconductor element at room temperature. Problems of adhesion of die attach materials to wire bond pads and bleed of die attach materials (a phenomenon in which only the liquid component of the die attach material is transmitted by capillary action) cannot be ignored.
Therefore, instead of using a liquid die attach material, a film die attach material is used. After the film die attach material is attached to a support, a semiconductor element is mounted while heating. A method for mounting a semiconductor element with a die attach material obtained by pasting on a dicing sheet after being attached to a dicing sheet in a state where the touch material is attached to a support while heating, a die attach film having a dicing sheet function For example, a method of mounting a semiconductor element with a die attach material obtained by pasting a semiconductor wafer and mounting it on a support while heating is employed. (For example, see Patent Documents 1 and 2.)
On the other hand, not only semiconductor elements but also supports have been made thinner for further multilayering of semiconductor elements and further thinning of semiconductor packages. When a thin support is used, the warping of the package based on the difference in the coefficient of thermal expansion of the semiconductor constituent material becomes more remarkable. In addition, in order to reduce the transmission delay due to the decrease in the signal propagation speed due to the parasitic capacitance between the wirings for increasing the speed of the semiconductor device, an insulating film having a low dielectric constant is applied to the interlayer insulating film. An insulating film having a low rate has a low mechanical strength, and warping of a semiconductor element sometimes causes destruction of the insulating film.
Here, since the warpage of the semiconductor package or the semiconductor element is caused by the difference in thermal expansion coefficient between the constituent members, it is desired to lower the temperature at which the semiconductor element is mounted when the film-like die attach material is used. In order to lower the semiconductor element mounting temperature of the film-like die attach material, it is necessary to use a thermoplastic component having a low glass transition temperature or increase a low molecular weight component, and as a result, tack (stickiness) occurs even near room temperature. Will occur.
Stickiness near room temperature often causes deterioration in pick-up property (step of removing a semiconductor element from a dicing sheet), and a step of placing the picked-up semiconductor element on another stage (see, for example, Patent Documents 3, 4, and 5). Cause sticking to the stage.
Here, several attempts have been proposed for a material having no tack at room temperature as a sealing material for a wafer level chip size package. (For example, refer to Patent Documents 6, 7, and 8.) In these inventions, a resin composition is applied to a wafer with bumps such as solder and heat-treated to make it tack free at room temperature, and then separated into individual pieces. However, since sealing and solder bonding are simultaneously performed in the next step, it is necessary to perform bonding at a temperature higher than the melting point of the solder.
Thus, there has been no liquid resin composition that can be used for an adhesive layer satisfying the requirements of a semiconductor element with an adhesive layer that can be mounted at a low temperature but has no stickiness at room temperature.

JP 2002-294177 A JP 2003-347321 A JP-A-6-132327 JP-A-7-201897 JP 2000-252303 A Japanese Patent Laid-Open No. 2000-174044 JP 2001-093940 A Japanese Patent Laid-Open No. 2003-221964

  The present invention is capable of mounting a semiconductor element with an adhesive layer on a support at a low temperature, generating less voids during mounting, and providing an adhesive layer for a semiconductor element with an adhesive layer that is not sticky at room temperature. A liquid resin composition to be used is provided, and a semiconductor wafer with an adhesive layer using an adhesive composed of the liquid resin composition, a semiconductor element with an adhesive layer, and a semiconductor element with the adhesive layer are used. A semiconductor package is provided.

Such an object is achieved by the present invention described in the following [1] to [8].
[1] A liquid resin composition comprising a compound (A) having a glycidyl group, a compound (B) having a phenolic hydroxyl group, and a solvent (C), wherein the compound having the glycidyl group is represented by the general formula (1) A liquid resin composition comprising the compound (A1).

G is a glycidyl group, and n is 0-5.

[2] The liquid resin composition according to [1], wherein the ratio of the compound (A1) to the compound (A) is 50% by weight or more and 100% by weight or less.
[3] The liquid resin composition according to [1] or [2], wherein the compound (B) includes a compound (B1) having a molecular weight of 1000 or less and a compound (B2) having a molecular weight of 1500 or more and 5000 or less.
[4] A semiconductor wafer with an adhesive layer, wherein an adhesive composed of the liquid resin composition according to any one of [1] to [3] is applied to one surface of the wafer.
[5] The semiconductor wafer with an adhesive layer according to [4], wherein the method of applying to one surface of the wafer is spin coating.
[6] A semiconductor element with an adhesive layer, wherein the semiconductor wafer with an adhesive layer according to [4] or [5] is cut.
[7] A semiconductor package assembled using the semiconductor element with an adhesive layer according to [6].
[8] Using the semiconductor element with an adhesive layer according to [6], assembling a semiconductor package in the order of mounting the semiconductor element with an adhesive layer on a support and performing a wire bond immediately after mounting. A method for assembling a semiconductor package.

  According to the present invention, a liquid resin composition used for an adhesive layer of a semiconductor element with an adhesive layer that can be mounted on a support at a low temperature on a support, has less voids when mounted, and does not stick at room temperature. Further, it is possible to provide a semiconductor package using the semiconductor element with the adhesive layer.

The liquid resin composition of the present invention comprises a compound (A) having a glycidyl group, a compound (B) having a phenolic hydroxyl group, and a solvent (C), and the compound (A) having a glycidyl group is represented by the general formula (1). A liquid resin composition comprising a compound (A1) represented by formula (1), wherein a semiconductor element with an adhesive layer can be mounted on a support at a low temperature, and voids are less likely to occur during mounting. And the liquid resin composition used for the adhesive bond layer of the semiconductor element with an adhesive bond layer which is not sticky at room temperature is provided. Here, examples of the support include a lead frame and an organic substrate.
Hereinafter, the present invention will be described in detail.

The compound (A) having a glycidyl group is an epoxy resin that has two or more glycidyl groups in the molecule and is a solid epoxy resin at room temperature, and includes a compound represented by the general formula (1). Since the compound represented by the general formula (1) has a larger epoxy equivalent (less glycidyl groups per unit weight) than an ortho-cresol novolac type epoxy resin, the water absorption rate can be kept low. If the water absorption rate can be kept low, the water absorption rate of the cured product becomes low, the dependency of the cured product property on the water absorption rate becomes small, and it becomes possible to obtain a cured product with high moisture resistance reliability. In addition, it is possible to reduce the water absorption rate when it is applied to one side of the wafer and then heat-treated, so the moisture absorbed when mounting the semiconductor element with an adhesive layer after dicing on an organic substrate is the cause. It is possible to suppress voids generated in Voids in the adhesive layer often cause peeling and must be suppressed.
Here, the compounding amount of the compound (A1) is preferably 50% by weight or more and 100% by weight or less, more preferably 60% by weight or more and 100% by weight or less, based on the whole compound (A). Particularly preferred is 75% by weight or more and 100% by weight or less. This is because a liquid resin composition having a low water absorption rate and high reliability can be obtained within the above range. The compound (A1) preferably has a softening point of 40 ° C. or higher and 80 ° C. or lower. If the softening point is lower than this, the tack force at 25 ° C. after coating and heating on one surface of the wafer may be higher than 0.05 N, and if higher than this, the tack force at 80 ° C. May be less than 1N.

  A compound having a glycidyl group other than the compound (A1) can also be used. Usable compounds having a glycidyl group have two or more glycidyl groups in one molecule, and those having a softening point of 40 ° C. or more and 80 ° C. or less are preferable. If the softening point is lower than this, the tack force at 25 ° C. after coating and heating on one surface of the wafer may be higher than 0.05 N, and if higher than this, the tack force at 80 ° C. May be less than 1N. Examples of such epoxy resins include phenol novolac type epoxy resins, cresol novolac type epoxy resins, biphenyl aralkyl type epoxy resins, dicyclopentadiene type epoxy resins, other epoxy resins having a triphenylmethine skeleton, epoxy resins having a naphthalene skeleton, An epoxy resin having an anthracene skeleton may be mentioned, but attention should be paid to those having high crystallinity because they may be deposited in the liquid resin composition or on one surface of the wafer after coating and heat treatment.

As the compound (B) having a phenolic hydroxyl group, a compound having two or more phenolic hydroxyl groups in one molecule is preferable. This is because when the number of phenolic hydroxyl groups contained in one molecule is 1, a crosslinked structure cannot be formed and sufficient cured product characteristics cannot be exhibited. Particularly preferred compounds (B) having a phenolic hydroxyl group include a compound (B1) having a molecular weight of 1000 or less and a compound (B2) having a molecular weight of 1500 or more and 5000 or less. Here, the molecular weight is a value of a number average molecular weight (Mn) measured by GPC (gel permeation chromatography). When only the compound (B1) having a molecular weight of 1000 or less is used, the tack force at 25 ° C., the tack force at 80 ° C., and the temperature at 25 ° C. after being applied to one surface of the wafer and heat-treated. Although the adhesive strength is excellent, the adhesive strength at 130 ° C. and the adhesive strength at 175 ° C. are too low. When a semiconductor element with an adhesive layer is mounted on a support and then wire bonding is performed without curing, the semiconductor element is May cause defects such as wire bond failure and peeling of the semiconductor element during resin sealing. By using a compound (B2) having a molecular weight of 1500 or more and 5000 or less in combination, an adhesive may be used. This is because the adhesive strength at 130 ° C. and 175 ° C. after the layered semiconductor element is mounted on the support is improved. On the other hand, when only compound (B2) is used as compound (B), the tack force at 80 ° C. after coating on one surface of the wafer and heat treatment deteriorates, making it impossible to mount at low temperature. . As for the ratio of a preferable compound (B1) and a compound (B2), (B1) / (B2) is 0.1-9, More preferably, it is 0.6-7, The still more preferable ratio is 0.8-3 is there.

  The compound (B1) is not particularly limited as long as it is a compound having two or more phenolic hydroxyl groups and a molecular weight of 1000 or less, and includes the following compounds. Bisphenols such as bisphenol A, bisphenol F, and bisphenol S, compounds obtained by reacting phenol or derivatives thereof such as phenol novolak and cresol novolak with formaldehyde, compounds obtained by reacting phenol or derivatives thereof with benzaldehyde, phenol aralkyl Type phenol resin, biphenyl aralkyl type phenol resin, other one having naphthalene skeleton, one having anthracene skeleton, and two phenolic hydroxyl groups (including hydroxyl groups directly bonded to aromatic rings such as naphthol type hydroxyl groups) in one molecule Examples thereof include compounds having the above. Even if the softening point of the compound (B1) is high, when it is mixed with an epoxy resin, the softening point of the mixture is lowered, so that even if the softening point is about 150 ° C., it can be used without any problem.

  The compound (B2) is not particularly limited as long as it is a compound having two or more phenolic hydroxyl groups and has a molecular weight of 1500 or more and 5000 or less, but a compound containing hydroxystyrene as a monomer component is particularly preferably used. Polyhydroxystyrene or hydroxystyrene copolymer obtained by radical polymerization or ionic polymerization with a compound copolymerizable with hydroxystyrene alone or having a molecular weight of 1500 or more and 5000 or less. More preferably, it is a polyhydroxystyrene or hydroxystyrene copolymer having a molecular weight of 1500 or more and 3000 or less, and in particular, the dispersity (ratio of weight average molecular weight (Mw) and number average molecular weight (Mn) determined by GPC) is Those having a size of 1.5 or less are particularly preferred because they can easily achieve both low-temperature mountability and adhesive strength at 130 ° C and 175 ° C after mounting. A more preferable dispersity is 1.3 or less.

  The ratio of the compound (A) to the compound (B) is preferably such that the phenolic hydroxyl group is 0.7 to 1.3 with respect to the glycidyl group 1. A more desirable ratio is 0.9 to 1.1 in terms of phenolic hydroxyl group per glycidyl group 1. It is also possible to mix a curing accelerator for the purpose of accelerating the reaction between the glycidyl group and the phenolic hydroxyl group. Examples of the curing accelerator that can be used include imidazoles and phosphorus compounds. Here, generally, a resin composition containing a photoinitiator that initiates a reaction by energy rays such as ultraviolet rays is well known, but in the present invention, a series of processes such as application of a liquid resin composition, heat treatment, dicing, and mounting of a semiconductor element. Since this operation is normally performed under illumination by a fluorescent lamp, it cannot contain a photoinitiator. When a photoinitiator is included, the viscosity of the liquid resin composition may change over time in a coating process of the liquid resin composition by spin coating, for example, and it may be difficult to obtain an adhesive layer having a stable thickness.

  In the present invention, the solvent (C) is used. The solvent (C) preferably has a boiling point of 100 ° C. or higher while dissolving the thermosetting resin because the liquid resin composition is applied to one surface of the wafer by screen printing, stencil printing, spin coating or the like. C. or lower is preferable. If the thermosetting resin does not dissolve, the surface after application will not be smooth, and there will be a risk of problems (such as flying chips) when singulated as described later. This is because there is a risk that it will remain. If the solvent used has a boiling point of 100 ° C. or lower, the viscosity change due to volatilization during coating may be remarkably non-uniform in thickness and may cause blurring. If the boiling point is higher than 240 ° C., after heat treatment This is because there is a possibility that the amount of volatile matter in the product becomes too large and stickiness may remain.

Such a solvent is not particularly limited as long as the solubility of the thermosetting resin used is sufficient, but a halogen-based solvent is not preferable because it is used for semiconductors. Moreover, the solvent which worsens the preservability of liquid resin compositions, such as an amine diluent containing a primary amine and a secondary amine, is not preferable. Solvents that can be used are as follows. These can be used alone or in combination of two or more. Octane, 2,2,3-trimethylpentane, nonane, 2,2,5-trimethylhexane, decane, dodecane, 1-octene, 1-nonene, 1-decene, toluene, o-xylene, m-xylene, p- Xylene, ethylbenzene, cumene, mesitylene, tetralin, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, p-cymene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, pentylbenzene, methylcyclohexane, ethylcyclohexane, p-menthane, bicyclohexyl, α-pinene, dipentene, decalin, 1-butanol, isobutyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert Pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2 -Heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1-nonanol, 3,5,5-trimethyl-1-hexanol, 1-decanol, benzyl alcohol, cyclohexanol, 1 -Methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, α-terpineol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1 , 3-butanediol, 1,4-butanedio 2,3-butanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, dibutyl ether, dihexyl ether, anisole, phenetole, butylphenyl ether, pentylphenyl ether, o-methoxy Toluene, m-methoxytoluene, p-methoxytoluene, benzyl ethyl ether, dioxane, 1,2-diethoxyethane, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 1-methylglycerin ether, 2-methyl Glycerol ether, 1,2-dimethylglycerol ether, 1,3-dimethylglycerol ether, trimethylglycerol ether, 1-ethylglycerol ether, 1,3-diethylglycerol ether Triethyl glycerin ether, acetal, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, acetonyl acetone, mesityl oxide, isophorone, cyclohexanone, methylcyclohexanone, butyl formate Pentyl formate, propyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isopentyl acetate, 3-methoxybutyl acetate, sec-hexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, acetic acid Cyclohexyl, benzyl acetate, butyl propionate, isopentyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isopentyl butyrate, isobutyl isobutyrate, ethyl isovalerate, benzoic acid Methyl acid, ethyl benzoate, propyl benzoate, γ-butyrolactone, diethyl oxalate, dipentyl oxalate, diethyl malonate, dimethyl maleate, diethyl maleate, tributyl citrate, ethylene glycol monoacetate, ethylene glycol diacetate , Ethylene glycol monoformate, ethylene glycol monobutyrate, diethylene glycol monoacetate, monoacetin, diethyl carbonate, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N, N ′ , N′-tetramethylurea, N-methylpyrrolidone, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxyethoxy) ethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, 1-methoxy-2-propanol, 1 -Ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, diacetone alcohol, N-ethylmorpholine, methyl lactate, ethyl lactate, butyl lactate, 2-methoxyethyl acetate, 2 -Ethoxyethyl acetate, 2-butoxyethyl acetate, diethylene glycol monoethyl ether acetate, aceto Methyl acid, ethyl acetoacetate. Particularly preferred diluents are those having a boiling point of 150 ° C. or higher and 220 ° C. or lower, and particularly preferred are diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 2-heptanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, 3-methoxybutyl acetate. Tart, 2-ethylbutyl acetate, γ-butyrolactone, ethylene glycol monoacetate, ethylene glycol diacetate, 2-butoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, 2 -Ethoxyethyl acetate, 2-butoxyethyl acetate, diethylene glycol monoethyl ether acetate It is.

  A thermoplastic resin can also be used in the liquid resin composition of the present invention. When a thermoplastic resin is used, the crosslink density of the cured product is lowered, and the elastic modulus of the cured product can be lowered. Preferable thermoplastic resins include phenoxy resins, (meth) acrylic acid ester polymers, and the like. In particular, ethyl (meth) acrylate or butyl (meth) acrylate as a main component, glycidyl (meth) acrylate, acrylonitrile, etc. A copolymerized compound is preferably used. However, if these thermoplastic resins have a high molecular weight and are used in an excessive amount, the tack force at 80 ° C. after being applied to one surface of the wafer and heat-treated may not be less than 1N. It is also possible to use a thermoplastic resin having a low glass transition temperature in order to keep the tack force at 80 ° C. after being applied to one side of the wafer and heat-treated at a good level. The tack force at 25 ° C. after coating on one surface of the wafer and heat treatment exceeds 0.05N, or the adhesive strength at 130 ° C. and 175 ° C. of the semiconductor element with an adhesive layer mounted on the support is low. There is a risk of becoming too much. For this reason, when using a thermoplastic resin, it is necessary to make it 40 weight% or less with respect to the sum total of a compound (A), a compound (B), and a thermoplastic resin. More preferably, it is 30% by weight or less.

Furthermore, in the liquid resin composition of the present invention, a coupling agent, a leveling agent, an antifoaming agent, a surfactant and the like can be used as necessary.
The liquid resin composition of the present invention is uniform by, for example, heating and mixing the compound (A), the compound (B), the solvent (C), and, if necessary, a thermoplastic resin in a mixing device equipped with a heating device and a stirrer. After obtaining such a liquid, it can be cooled to room temperature, added with additives such as a curing accelerator and a coupling agent, and further mixed.

The liquid resin composition of the present invention is prepared by laminating a semiconductor wafer having a bonding pad for wire bonding (the back side of the circuit surface) or one side of the wafer on which no circuit is written (a plurality of semiconductor elements are laminated). In case of using a chip without a circuit written as a spacer in order to secure the loop height of the bonding wire of the lower semiconductor element in the semiconductor package) To explain. Usually, the semiconductor wafer is subjected to back surface grinding before the dicing step for the purpose of controlling the thickness, but the liquid resin composition is applied after the back surface grinding. The liquid resin composition can be applied by screen printing, stencil printing, spin coating, or the like, but is preferably applied by spin coating from the viewpoint of coating thickness stability and surface smoothness. Spin coating can be performed by a known method. That is, a wafer with a back grind tape (tape attached to the circuit surface for the purpose of protecting the circuit surface of the wafer during back surface grinding) is set on a spin coater so that the back surface of the wafer faces up, and is 15 ° C. or more and 40 ° C. In the following, the liquid resin composition is uniformly applied to the entire back surface of the wafer by supplying the liquid resin composition to the center of the wafer and rotating the wafer. Since the back grind tape to be used has a heat treatment step to be described later, one having excellent heat resistance is preferable, and one having a wafer support function (function to suppress warping and deformation of a wafer thinned after back surface polishing) is also preferable. If the temperature of the spin coating is lower than this, the viscosity of the liquid resin composition becomes high and the thickness after coating may not be uniform, which is not preferable. If it is higher than this, the viscosity change due to volatilization of the liquid resin composition Is undesirable because it can cause non-uniformity in coating thickness. A more preferable temperature range is 20 ° C. or higher and 30 ° C. or lower. In order to obtain a more stable coating thickness, coating in an environment controlled to ± 2 ° C. is preferable. The number of rotations of the wafer depends on the viscosity of the liquid resin composition to be used, the coating temperature, and the target coating thickness, but is usually 300 rpm or more and 10,000 rpm or less. The liquid resin composition can be supplied while the wafer is stopped, and the number of rotations can be gradually increased, or the number of rotations can be increased if necessary by supplying the resin composition while rotating at a low rotation speed of 300 rpm. .

Next, the semiconductor wafer coated with the liquid resin composition is subjected to heat treatment. The heat treatment can be a treatment on a hot plate, a treatment in an oven, a treatment in a reflow furnace, and the like. The treatment temperature is preferably 200 ° C. or lower, and more preferably 150 ° C. or lower. This is because the warping after the treatment is smaller in the treatment at a low temperature. The treatment time is preferably 30 minutes or less. When the processing time is longer than this, productivity is deteriorated and the warpage after the processing is disadvantageous. Particularly preferred heat treatment conditions are 150 ° C. or less and 15 minutes or less.
The thickness of the adhesive layer after the heat treatment is preferably 200 μm or less, and more preferably 5 μm or more and 50 μm or less. The thickness can be controlled by adjusting the coating conditions and adjusting the viscosity of the liquid resin composition. For example, if a low-viscosity liquid resin composition is used, it is possible to obtain a thinner adhesive layer. When spin coating is used as a coating method, a thinner adhesive can be obtained by increasing the number of revolutions during coating. It becomes possible to obtain a layer. When a film-like die attach material is used, a film having a desired thickness must be prepared. However, the present invention is that the thickness can be controlled by adjusting the coating conditions and the viscosity of the liquid resin composition. Is one of the advantages.

  If a large amount of volatile matter is contained in the adhesive layer after heat treatment, it may cause stickiness of the adhesive layer, which will be described later, cause deterioration of pickup properties, and cause voids when mounted on the support. It is preferable that the volatile content after the resin composition is applied to the back surface of the wafer to a thickness of 50 μm and heat-treated at 120 ° C. for 10 minutes is 1% by weight or less. Here, the thickness of the liquid resin composition after coating is a value measured with a non-contact thickness meter, and the volatile content is controlled to 120 ± 5 ° C. for a wafer coated with the liquid resin composition at 50 ± 5 μm. After heat treatment for 10 ± 1 minutes in a dryer, 5 to 30 mg of an adhesive layer sampled with a spatula before the taken-out wafer is cooled is 10 ° C / 300 ° C from room temperature to 300 ° C by thermobalance (TGA). It is the weight loss rate at 200 ° C. in the weight loss curve measured by raising the temperature in minutes. A more preferred weight loss rate is 0.5% by weight or less, and particularly preferred is 0.2% by weight or less.

  The adhesive layer preferably has no tack (stickiness) at room temperature. If there is stickiness, there is a risk that a conveyance failure may occur in the wafer mounting process to be attached to the dicing sheet, and a defect may also occur in the pickup process described later. For this reason, the adhesive layer after applying the liquid resin composition to the back surface of the wafer to a thickness of 50 μm and heat-treating at 120 ° C. for 10 minutes has a tack force at 25 ° C. of 0.05 N or less, which is an index of stickiness. Is preferred. The tack force is measured using a tack force measuring machine (manufactured by RHESCA) at a probe descending speed (Immersion Speed) of 30 mm / min, a test speed of 600 mm / min, a contact load (Preload) of 0.2 N, and a contact holding time (Press Time) of 1.0. This is a value measured with a probe of 5.1 mmφ (SUS304). That is, a wafer coated with a liquid resin composition of 50 ± 5 μm is heated in a dryer controlled at 120 ± 5 ° C. for 10 ± 1 minutes, cooled, and then dicing sheet (Sumitomo Bakelite) with the adhesive layer facing down. From the dicing sheet, a part of the semiconductor element with an adhesive layer separated into 6 × 6 mm obtained by pasting to 6 × 6 mm with a dicing saw attached to FSL-N4003 manufactured by Co., Ltd. by hand Peeling The tack force on the adhesive layer side was measured at 25 ° C. by the above-described tack force measurement method.

The thickness accuracy of the adhesive layer of the wafer with the adhesive layer is preferably within ± 5 μm, and more preferably within ± 3 μm. Here, the thickness accuracy is a distance from the average value of the surface profile obtained by measuring a change in the unevenness in the chip surface with a laser roughness meter. This is because when the thickness accuracy is larger than this, a stable thickness cannot be obtained.
Next, the semiconductor wafer with an adhesive layer is attached to a dicing sheet and separated into individual pieces. A commercially available dicing sheet can be used. Separation is usually performed using a dedicated device such as a dicing saw to obtain a semiconductor element with an adhesive layer. Here, when the smoothness of the adhesive layer is not sufficient as described above, air may remain between the adhesive layer and the dicing sheet. For this reason, chip chipping (a phenomenon that chip edge portions are chipped) ), Chip cracks (a phenomenon in which the chip edge is cracked), chip jumps (a phenomenon in which the chip is detached from the dicing sheet during dicing), and the like, resulting in deterioration of the yield of the semiconductor element with the adhesive layer There is.
The semiconductor element with the adhesive layer thus obtained is set on a die bonder in a state where it is attached to the dicing sheet (the dicing sheet is attached to the wafer ring) and picked up (the process of taking the semiconductor element from the dicing sheet) And mounted on a support under heating. When picking up, it is necessary to peel off at the interface between the semiconductor element with the adhesive layer and the dicing sheet. If the tacking force of the adhesive layer is greater than 0.05N, picking up is impossible. There is a risk that a part of the adhesive layer remains on the dicing sheet.

The support on which the semiconductor element with the adhesive layer is mounted is a lead frame, an organic substrate, or the like, and when the semiconductor elements are stacked, it is a second semiconductor element mounted on the lead frame, the organic substrate, or the like. The semiconductor element mounting temperature is preferably 200 ° C. or lower, and more preferably 150 ° C. or lower. This is because mounting a semiconductor element at a high temperature often causes warping. A load is applied when a semiconductor element is mounted, but the load is governed by the type of die bonder. Some models, such as some LOC bonders, can apply a load of about 20 N per semiconductor element, but are usually performed with a load of about 3 to 5 N. In consideration of thin semiconductor elements and low mechanical strength semiconductor elements, it is preferable that the semiconductor elements can be mounted at 5N or less, more preferably 1 to 4N. The mounting time (the time during which the semiconductor element is pressed against the support) is preferably 10 seconds or less from the viewpoint of productivity, more preferably 3 seconds or less, and particularly preferably 1 second or less. Thus, in order to mount the semiconductor element at a low temperature, the adhesive force after the liquid resin composition is applied to the back surface of the wafer with a thickness of 50 μm and then heat-treated at 120 ° C. for 10 minutes is 80 ° C. It is preferable that it is 1N or more. As a result of mounting experiments on a PBGA substrate using various adhesive layers with different adhesive layers at 80 ° C. of the adhesive layer after heat treatment, the tack force at 80 ° C. is 1 N or more. In this case, the adhesion area after mounting can be ensured to be 90% or more, whereas when it is less than 1N, the adhesion area is often less than 90%. Here, the adhesion area after mounting was confirmed by peeling the semiconductor element after mounting on the PBGA substrate by hand, and the area of the bonding portion relative to the area of the semiconductor element. The bonded part feels somewhat whitish on the surface of the PBGA substrate, whereas the non-adhered part is smooth and the surface is not changed from that before mounting and can be easily identified visually. The tack force at 80 ° C. is that the wafer with the liquid resin composition applied to 50 ± 5 μm is heat-treated for 10 ± 1 minutes in a dryer controlled at 120 ± 5 ° C. and cooled, and then the adhesive layer becomes lower. Of a semiconductor element with an adhesive layer separated into 6 × 6 mm obtained by attaching to a dicing sheet (FSL-N4003, manufactured by Sumitomo Bakelite Co., Ltd.) and dicing to 6 × 6 mm with a dicing saw The part was peeled off from the dicing sheet by hand, and the tack force on the adhesive layer side was measured at 80 ° C. by the tack force measurement method.
Also, the semiconductor element with the adhesive layer separated into 6 × 6 mm is picked up on a die bonder, bond weight is 1.0 N, substrate heating temperature is 130 ° C., mounting time is 8 seconds (the substrate surface temperature is raised to 130 ° C. PBGA substrate (package size 35 × 35 mm, core material: BT (bismaleimide-triazine), solder resist: PSR4000AUS308 (manufactured by Taiyo Ink Manufacturing Co., Ltd.), thickness 0.56 mm) It is preferable that the adhesive force at 25 ° C. of the mounted adhesive force measurement sample is 10 N or more. The measurement of adhesive force is a value measured with a die shear tester (manufactured by Dage, series 4000). If the adhesive force is lower than this, the semiconductor element may fall off during transportation. More preferably, it is 20N or more, and more preferably 50N or more.
Next, wire bonding is performed for the purpose of electrically connecting the semiconductor element mounted on the support and the support. The conditions for wire bonding are not particularly limited and can be carried out under normal conditions using a commercially available wire bonder. However, it is preferably carried out at a low temperature in consideration of the above-mentioned problem of warpage. A particularly preferred wire bond temperature is 150 ° C. or lower. Here, the adhesive strength at 130 ° C. of the sample for measuring the adhesive strength (the semiconductor element with the adhesive layer separated into 6 × 6 mm is mounted on the PBGA substrate and the adhesive layer is not cured) is 10N. The above is more preferable because the wire bonding can be performed without curing the adhesive after the semiconductor element with the adhesive layer is mounted on the support. Particularly preferred adhesive strength at 130 ° C. is 30 N or more. If it is more than this, it is because a wire bond defect (a wire does not adhere, wire bonding strength is low, etc.) does not occur in the wire bonding process.

Next to the wire bond, a resin sealing process is performed. Usually, a sealing material for transfer molding in which a filler is dispersed in an epoxy resin is used. Usable transfer molding encapsulants are not particularly limited, but those not using an antimony compound or brominated compound are preferred because of environmental problems. More preferable is a sealing material using a biphenyl aralkyl type epoxy resin and / or a biphenyl aralkyl type phenol resin, which does not use an antimony compound or a brominated compound. The encapsulant using the biphenyl aralkyl type epoxy resin and / or the biphenyl aralkyl type phenol resin exhibits good flame resistance (UL test V-0) and good reflow resistance without using an antimony compound or brominated compound. It is because it shows cracking properties.
Resin sealing is usually performed at 160 ° C to 180 ° C. For this reason, when the adhesive force to the support body of the semiconductor element after wire bonding is too low, there is a risk that the semiconductor element may be peeled off during the resin sealing process or the semiconductor element may be washed away. For this reason, 175 ° C. (typical resin sealing) of the above-mentioned sample for measuring adhesive force (the adhesive layer is not cured only by mounting the semiconductor element with the adhesive layer separated into 6 × 6 mm on the PBGA substrate) It is preferable that the adhesive strength at the (stopping temperature) is 1 N or more. Particularly preferred is 3N or more. This is because if the adhesive strength is higher than this, problems such as peeling do not occur during resin sealing.
After resin sealing, post mold curing is performed as necessary, and in the case of using a lead frame as a support, lead processing, exterior plating, etc. are performed as necessary to obtain a semiconductor package. When an organic substrate is used as the support, a semiconductor package is obtained by performing solder ball attachment or the like as necessary.

Further, in the liquid resin composition used in the present invention, the ratio (b / a) of the area (b) having a molecular weight of 200 or more and 5000 or less to the area (a) having a molecular weight of 200 or more in GPC measurement is (b / a)> 0. A liquid resin composition satisfying .6. Preferably (b / a)> 0.7, more preferably (b / a)> 0.8. When (b / a) is smaller than this, the tack force at 80 ° C. of the heat treatment becomes insufficient, and the mountability of the semiconductor element with an adhesive layer may be deteriorated. Here, GPC measurement was performed using Waters Alliance (2695 Separations Module, 2414 Refractive Index Detector, TSK Gel GMHHR-Lx2 + TSK Guard Column HHR-Lx1, mobile phase: THF, 1.0 ml / min). The measurement was performed at 0 ° C., a differential refractometer internal temperature of 40.0 ° C., a sample injection amount of 100 μl, and a sample concentration of 1 to 5 mg / ml. A calibration curve of molecular weight was prepared using Shodex Standard SL-105 (manufactured by Showa Denko KK).
Furthermore, the liquid resin composition of the present invention has a molecular weight with respect to an area (a ′) having a molecular weight of 200 or more in GPC measurement of the adhesive layer after being applied to one side of the wafer to a thickness of 50 μm and heat-treated at 120 ° C. for 10 minutes. When the ratio of the area (b ′) between 200 and 5000 is (b ′ / a ′), the ratio [(b ′ / a ′) / (b / a)] to the B / A is It is preferable to satisfy. [(B ′ / a ′) / (b / a)]> 0.7. If [(b ′ / a ′) / (b / a)] is smaller than this, the tack force at 80 ° C. after the heat treatment becomes insufficient, and the mountability of the semiconductor element with an adhesive layer may be deteriorated. There is sex.
When the liquid resin composition is applied to one surface of the wafer by spin coating, the presence of micron-sized solids in the liquid resin composition deteriorates the smoothness of the surface of the adhesive layer after heat treatment. This is not preferable because it causes generation of hole voids. For this reason, it is necessary to pay sufficient attention to the precipitation of the thermosetting resin and curing accelerator used in the liquid resin composition. When preparing the liquid resin composition, it is preferable to filter through a 10 μm filter, more preferably after filtering through a 10 μm filter, and then through a 3 μm filter, and particularly preferably through a 1 μm filter. . Moreover, a filler cannot be used. The viscosity of the liquid resin composition is preferably 1 Pa · s or more and 40 Pa · s or less. This is because an adhesive layer having a good thickness cannot be obtained after spin coating, either lower or higher. Here, the value of the viscosity is a value measured at 25 ° C. and 2.5 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., 3 ° cone). A more preferable viscosity range is 2 Pa · s or more and 30 Pa · s or less, and further preferable is 2 Pa · s or more and 15 Pa · s or less.

Hereinafter, the present invention will be described using examples, but the present invention is not limited thereto.
[Adjustment of liquid resin composition]
-Liquid resin composition A
Phenol aralkyl type epoxy resin (softening point 52 ° C., epoxy equivalent 238, compound represented by general formula (1))
35.5g
Phenol aralkyl resin (molecular weight 612, softening point 75 ° C., hydroxyl group equivalent 175) 10.6 g
Polyhydroxystyrene (molecular weight 2080, dispersity 1.26) 10.6 g
γ-butyrolactone (boiling point 204 ° C.) 42.9 g
The above raw materials were blended in a separable flask and stirred at 150 ° C. for 1 hour to obtain a pale yellow transparent liquid. After cooling this to room temperature, the following raw materials were added, and after stirring at room temperature for 30 minutes, liquid resin composition A was obtained by filtering through a 1 μm mesh.
3-glycidoxypropyltrimethoxysilane 0.26 g
Phosphorus catalyst 0.17g
The phosphorus catalyst used here and the phosphorus catalyst used in the liquid resin compositions B to F were prepared as follows.
6. 4,4′-bisphenol S (BPS-N manufactured by Nikka Chemical Co., Ltd.) 3 in a separate flask with a stirrer 5 g (0.15 mol), tetraphenylphosphonium promide 4 9 g (0.1 mol) and 100 ml of ion-exchanged water were charged and stirred at 100 ° C. Further, while the inside was insoluble, a solution prepared by dissolving 4.0 g (0.1 mol) of sodium hydroxide in advance with 50 ml of ion-exchanged water was added with stirring. After stirring for a while, a white precipitate was obtained. The precipitate was filtered and dried, and the resulting white crystals (68.5 g) were used as a catalyst.
The viscosity of the obtained liquid resin composition A was 4 Pa · s. The viscosity is measured at 25 ° C. and 2.5 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., 3 ° cone) (the viscosity shown below was also measured in the same manner).

-Liquid resin composition B
Phenol aralkyl type epoxy resin (softening point 52 ° C., epoxy equivalent 238, compound represented by general formula (1))
18.3g
Phenol aralkyl resin (molecular weight 612, softening point 75 ° C., hydroxyl group equivalent 175) 5.5 g
Polyhydroxystyrene (molecular weight 2080, dispersity 1.26) 5.5 g
Acrylic polymer (ethyl acrylate / acrylonitrile / glycidyl acrylate / N, N-dimethylacrylamide = 74/20/1/5 copolymer, molecular weight: 490,000, Tg: 15 ° C.)
9.7g
γ-butyrolactone (boiling point 204 ° C.) 60.8 g
The above raw materials were blended in a separable flask and stirred at 150 ° C. for 1 hour to obtain a pale yellow transparent liquid. After cooling this to room temperature, the following raw materials were added, and after stirring at room temperature for 30 minutes, liquid resin composition B was obtained by filtering with a 1 μm mesh.
3-glycidoxypropyltrimethoxysilane 0.13 g
Phosphorus catalyst 0.09g
The viscosity of the obtained liquid resin composition B was 8 Pa · s.

・ Liquid resin composition C
Phenol aralkyl type epoxy resin (softening point 52 ° C., epoxy equivalent 238, compound represented by general formula (1))
20.8g
Orthocresol novolac type epoxy resin (softening point 70 ° C., epoxy equivalent 210) 13.9 g
Phenol aralkyl resin (molecular weight 612, softening point 75 ° C., hydroxyl group equivalent 175) 10.9 g
Polyhydroxystyrene (molecular weight 2080, dispersity 1.26) 10.9g
γ-butyrolactone (boiling point 204 ° C.) 43.0 g
The above raw materials were blended in a separable flask and stirred at 150 ° C. for 1 hour to obtain a pale yellow transparent liquid. After cooling this to room temperature, the following raw materials were added, and after stirring at room temperature for 30 minutes, liquid resin composition C was obtained by filtering with a 1 μm mesh.
3-Glycidoxypropyltrimethoxysilane 0.25g
Phosphorus catalyst 0.17g
The viscosity of the obtained liquid resin composition C was 5 Pa · s.

・ Liquid resin composition D
Orthocresol novolak type epoxy resin (softening point 70 ° C., epoxy equivalent 210) 33.6 g
Phenol aralkyl resin (molecular weight 612, softening point 75 ° C., hydroxyl group equivalent 175) 11.4 g
11.4 g of polyhydroxystyrene (molecular weight 2080, dispersity 1.26)
γ-butyrolactone (boiling point 204 ° C.) 43.1 g
The above raw materials were blended in a separable flask and stirred at 150 ° C. for 1 hour to obtain a pale yellow transparent liquid. After cooling this to room temperature, the following raw materials were added, and after stirring at room temperature for 30 minutes, liquid resin composition D was obtained by filtering through a 1 μm mesh.
3-Glycidoxypropyltrimethoxysilane 0.25g
Phosphorus catalyst 0.17g
The viscosity of the obtained liquid resin composition D was 6 Pa · s.

・ Liquid resin composition E
Orthocresol novolac type epoxy resin (softening point 70 ° C., epoxy equivalent 210) 32.7 g
Phenol aralkyl resin (molecular weight 612, softening point 75 ° C., hydroxyl group equivalent 175) 27.2 g
γ-butyrolactone (boiling point 204 ° C.) 39.7 g
The above raw materials were blended in a separable flask and stirred at 150 ° C. for 1 hour to obtain a pale yellow transparent liquid. After cooling this to room temperature, the following raw materials were added, and after stirring at room temperature for 30 minutes, liquid resin composition E was obtained by filtering with a 1 μm mesh.
3-glycidoxypropyltrimethoxysilane 0.27 g
Phosphorus catalyst 0.18g
The viscosity of the obtained liquid resin composition E was 3 Pa · s.

・ Liquid resin composition F
Orthocresol novolac type epoxy resin (softening point 90 ° C., epoxy equivalent 210) 34.4 g
Polyhydroxystyrene (molecular weight 1850, dispersity 2.41) 19.6g
γ-butyrolactone (boiling point 204 ° C.) 45.6 g
The above raw materials were blended in a separable flask and stirred at 150 ° C. for 1 hour to obtain a pale yellow transparent liquid. After cooling this to room temperature, the following raw materials were added, and after stirring at room temperature for 30 minutes, liquid resin composition F was obtained by filtering with a 1 μm mesh.
3-glycidoxypropyltrimethoxysilane 0.24 g
Phosphorus catalyst 0.16g
The viscosity of the obtained liquid resin composition F was 12 Pa · s.

[Example 1]
20 mg of the liquid resin composition A was dissolved in 6 ml of tetrahydrofuran (hereinafter THF), and GPC was measured. GPC measurement was performed using Waters Alliance (2695 Separations Module, 2414 Refractive Index Detector, TSK Gel GMHHR-Lx2 + TSK Guard Column HHR-Lx1, mobile phase: THF, 1.0 ml / min), column temperature 40.0 ° C. The measurement was performed under the conditions of a differential refractometer internal temperature of 40.0 ° C. and a sample injection amount of 100 μl. The calibration curve of molecular weight is Shodex Standard SL-105
(Made by Showa Denko KK). The ratio (b / a) of the area (b) having a molecular weight of 200 or more and 5000 or less to the area (a) having a molecular weight of 200 or more in the obtained GPC chart was calculated.
Also, a 6-inch wafer (bare silicon with no circuit written, thickness 625 μm) and an 8-inch wafer (liquid copper composition 0.5% copper pad with passivation SiN, thickness 350 μm) using the liquid resin composition A One wafer was spin-coated so that the thickness after application was 50 ± 5 μm, and heat-treated in a dryer adjusted to 120 ° C. for 10 minutes to obtain a wafer with an adhesive layer. The spin coating was performed using a spin coater (Mikasa Co., Ltd., 1H-DX). The thickness after spin coating was measured with a non-contact thickness meter, and when the thickness was not 50 ± 5 μm, the spin coating conditions were changed so as to fall within the above range.

A 6-inch wafer was immediately collected after heat treatment by collecting a part of the adhesive layer with a spatula, and used as a sample for measuring volatile content. The volatile content is a value of a weight reduction rate at 200 ° C. measured with a TGA (differential thermal balance) at a sample weight of 10 mg and a temperature rising rate of 10 ° C./min from room temperature. The reason for sampling immediately after the heating is that when cooled to room temperature, the adhesive layer becomes solid and sampling may be difficult. Further, an appearance check was performed visually using portions other than the sampled portions. Appearance check checked the number of pinhole voids and foreign objects. The thickness of the adhesive layer was calculated by measuring the total thickness of the wafer and the adhesive layer using a contact-type thickness gauge, and subtracting the thickness of the wafer measured in advance. Furthermore, regarding the thickness accuracy, a laser three-dimensional measuring machine (manufactured by Hitachi Tsuchiura Engineering Co., Ltd.) is used, and the length is 150 mm so as to pass through the center of the wafer with the adhesive layer without passing through the part sampled for volatile matter measurement. The measurement was performed.
Next, a 6-inch wafer and an 8-inch wafer with an adhesive layer were attached to a dicing sheet (FSL-N4003, manufactured by Sumitomo Bakelite Co., Ltd.) and separated into pieces of 6 × 6 mm and 10.5 × 10.5 mm, respectively. A part of a 6-inch wafer separated into 6 × 6 mm pieces was peeled off from the dicing sheet by hand and used for measuring the tack force of the adhesive layer at 25 ° C. and 80 ° C. The tack force is measured using a tack force measuring machine (manufactured by RHESCA), probe lowering speed (Immersion Speed) 30 mm / min, test speed 600 mm / min, adhesion load (Preload) 0.2 N, adhesion holding time (Press Time) 1 0.0 second, probe 5.1 mmφ (SUS304).
Similarly, three semiconductor elements with an adhesive layer separated into 6 × 6 mm pieces, which were peeled off by hand, were immersed in 6 ml of THF and permeated at 25 ° C. for 60 minutes to obtain a GPC measurement sample. A ratio (b ′ / a ′) of an area (b ′) having a molecular weight of 200 or more and 5000 or less to an area (a ′) having a molecular weight of 200 or more was calculated from a GPC chart measured under the same conditions as described above, and [[b ′ / a ′) / (b / a)] was calculated.
Further, the following items were evaluated as described later.

・ Adhesive strength A wafer with an adhesive layer separated into 6 x 6 mm is attached to a die bonder, the ejector pin height is 350 μm (dicing film bottom surface is 0), pick-up time is 500 ms, bond load is 1.0 N, substrate heating temperature PBGA substrate (package size 35 × 35 mm, core material: BT (bismaleimide-triazine), solder resist: PSR4000AUS308 under conditions of 130 ° C. for 8 seconds (including 7 seconds for the substrate surface temperature to rise to 130 ° C.) (Manufactured by Taiyo Ink Manufacturing Co., Ltd.), with a thickness of 0.56 mm). The adhesive strength of the sample after mounting (not cured) was measured at room temperature, 130 ° C., and 175 ° C. The adhesion was measured with a die shear tester (manufactured by Dage, series 4000).・ Void (1)
The wafer with the adhesive layer separated into 6 × 6 mm pieces was manually peeled off from the dicing sheet and immersed in pure water at 25 ° C. Using a wafer with an adhesive layer separated into individual pieces immersed in pure water at 25 ° C. for 1 hour, the wafer was mounted on a slide glass with a simple mounter under conditions of a bond load of 0.5 N, a bond temperature of 130 ° C., and a bond time of 1 second. The occurrence of voids in the sample after mounting (not cured) and the sample cured at 150 ° C. for 60 minutes were observed from the back of the slide glass. The case where the void area (void area / 36 mm ² ) by image processing was 5% or less was regarded as acceptable.

・ Void (2), initial peeling 1 Wafer with adhesive separated into 10.5 x 10.5 mm was left in an atmosphere of 30 ° C and 85% RH for 72 hours together with a dicing sheet, then attached to a die bonder and ejector pin height 350 µm (dicing The bottom surface of the film was picked up under the conditions of 0), pick-up time of 500 ms, and bonded to a PBGA substrate (package size 35 × 35 mm, core material: BT (bonding load 2.9 N, substrate heating temperature 130 ° C. 8 seconds (including heating time)) Bismaleimide-triazine), solder resist: PSR4000AUS308 (manufactured by Taiyo Ink Manufacturing Co., Ltd.), thickness 0.56 mm) (without curing), wire bonding was performed under the following conditions.
Wire bonder: Eagle 60 (manufactured by ASM)
Gold wire: SGS-H, 25 μm (manufactured by Sumitomo Metal Mining Co., Ltd.)
Wire bond temperature: 130 ° C
Bonding load: 45g
Ultrasonic power: 120 (128 kHz)

After performing wire bonding, it was sealed with an epoxy-based sealing resin (Sumitomo Bakelite Co., Ltd., EME-G770) using biphenyl aralkyl epoxy, and post mold curing was performed at 175 ° C. for 4 hours. The occurrence of void (2) and initial peeling was confirmed by observing the PBGA package after post mold curing with a transmission type ultrasonic flaw detector. Void (2) and initial peeling were confirmed by the ratio of the area of the ultrasonically opaque part (black part) to the area of the chip.
・ Solder reflowability test Void (2), package subjected to initial peeling observation was subjected to moisture absorption treatment at 85 ° C. and 60% RH for 168 hours, and then set so that the time at 260 ° C. or higher was 10 seconds or longer. After passing through the IR reflow device three times, the occurrence of cracks was observed with a transmission type ultrasonic flaw detector. Of the four packages used in the test, the number of cracked packages is shown.
The measurement results are shown in Table 1.

[Example 2]
Evaluation was performed in the same manner as in Example 1 except that the liquid resin composition B was used.
[Example 3]
Evaluation was performed in the same manner as in Example 1 except that the liquid resin composition C was used.

[Comparative Examples 1-3]
Evaluation was performed in the same manner as in Example 1 using the liquid resin compositions D to F.

  In Example 1, the volatile content after spin coating / heat treatment was small, the appearance was good, and the thickness accuracy was also good. Further, the tack forces at 25 ° C. and 80 ° C. were 0.02 N and 2.2 N, respectively, and the pick-up property was good, and wire bonding was possible without curing after mounting the semiconductor element. In the package after sealing, neither void nor peeling occurs, and no crack occurs after solder reflow.

In Example 2, the volatile content after spin coating / heat treatment was small, the appearance was good, and the thickness accuracy was also good. Further, the tack forces at 25 ° C. and 80 ° C. were 0.02N and 3.1N, respectively, and the pick-up property was good, and wire bonding was possible without curing after mounting the semiconductor element. In the package after sealing, neither void nor peeling occurs, and no crack occurs after solder reflow.

  In Example 3, the volatile content after spin coating / heat treatment was small, the appearance was good, and the thickness accuracy was also good. Further, the tack force at 25 ° C. and 80 ° C. was 0.02 N and 2.0 N, respectively, and the pick-up property was good, and wire bonding was possible without curing after mounting the semiconductor element. In the package after sealing, neither void nor peeling occurs, and no crack occurs after solder reflow.

  Comparative Example 1 had little volatile content after spin coating / heat treatment, good appearance, and good thickness accuracy. Further, the tack force at 25 ° C. and 80 ° C. was 0.02 N and 1.8 N, respectively, and the pick-up property was good, but a void was generated at the time of mounting and a crack was generated after solder flow starting from the void.

  In Comparative Example 2, the volatile content after spin coating / heat treatment was small, the appearance was good, and the thickness accuracy was also good. The tack force at 25 ° C. and 80 ° C. was 0.02N and 2.4N, respectively, and the pick-up property was good, but the compound (B2) (a compound having a phenolic hydroxyl group with a molecular weight of 1500 to 5000) was used. In addition, since the adhesive strength at 130 ° C. and 175 ° C. was low and the chip flowed at the time of sealing, the void (2), observation of initial peeling, and evaluation of cracks after solder reflow could not be performed.

  In Comparative Example 3, the volatile content after spin coating / heat treatment was small, the appearance was good, and the thickness accuracy was also good. Further, the tack force at 25 ° C. was 0.02N, and the pickup property was good, but the compound (B1) (compound having a phenolic hydroxyl group having a molecular weight of 1000 or less) was not contained and the compound (B2) (molecular weight 1500) Since it contains only a compound having a phenolic hydroxyl group of 5000 or less, the tack force at 80 ° C. is 0.1 N, and the semiconductor element cannot be mounted on the support under the same conditions as in Example 1. Although the evaluation was continued by changing the mounting conditions, the semiconductor element was peeled off at the time of wire bonding, and sealing could not be performed.

  By using the liquid resin composition of the present invention, it is possible to mount a semiconductor element with an adhesive layer on a support at a low temperature, there is little generation of voids during mounting, and there is no stickiness at room temperature. It is possible to provide a semiconductor package using the semiconductor element with the adhesive layer.

Claims (7)

A liquid resin composition used for an adhesive layer of a semiconductor element comprising a compound (A) having a glycidyl group, a compound (B) having a phenolic hydroxyl group, and a solvent (C), the compound having the glycidyl group ( see containing a) is represented by the general formula (1) compound (A1), the compound (B) is a molecular weight of 1000 or less phenol aralkyl resin (B1) and a molecular weight of 1500 or more 5000 or less is polyhydroxystyrene (B2) And the ratio of the compound (A) to the compound (B) is such that the phenolic hydroxyl group of the compound (B) is 0.7 to 1 with respect to the glycidyl group 1 of the compound (A). A liquid resin composition characterized by the fact that it is .3 .


G is a glycidyl group, and n is 0-5. The liquid resin composition according to claim 1, wherein a ratio of the compound (A1) to the compound (A) is 50% by weight or more and 100% by weight or less. A semiconductor wafer with an adhesive layer, wherein an adhesive composed of the liquid resin composition according to claim 1 or 2 is applied to one surface of the wafer. The semiconductor wafer with an adhesive layer according to claim 3 , wherein the method of applying to one surface of the wafer is spin coating. A semiconductor element with an adhesive layer, wherein the semiconductor wafer with an adhesive layer according to claim 3 or 4 is cut. A semiconductor package assembled using the semiconductor element with an adhesive layer according to claim 5 . A semiconductor package is assembled in the order of a step of mounting a semiconductor element with an adhesive layer on a support and a step of wire bonding immediately after mounting, using the semiconductor element with an adhesive layer according to claim 5. A method for assembling a semiconductor package.