JP4835229B2 - Resin composition and semiconductor device produced using resin composition - Google Patents

Description

  The present invention relates to a resin composition and a semiconductor device manufactured using the resin composition.

  In the market trend of downsizing, weight reduction, and high performance of electronic devices, higher integration of semiconductor elements has been progressing year by year, and surface mounting of semiconductor devices has been promoted. In recent years, ball grid arrays (hereinafter referred to as BGA) called surface mount type semiconductor devices represented by conventional QFP, SOP, etc., or chip size packages (hereinafter referred to as CSP) in pursuit of further miniaturization. ). This was developed because conventional semiconductor devices are approaching the limits of increasing the number of pins and increasing the speed of semiconductor elements. As a structure, a semiconductor element is formed on one surface of a hard circuit board represented by a bismaleimide-triazine (hereinafter referred to as BT) resin / copper foil circuit board or a flexible circuit board represented by a polyimide resin film / copper foil circuit board. After that, only the semiconductor element mounting surface, that is, one surface of the substrate is molded and sealed with the epoxy resin composition. In recent years, replacement with lead-free solder has been promoted as part of not using environmentally hazardous substances. Since lead-free solder has a higher melting point than conventional leaded solder, the soldering temperature at the time of surface mounting is required to be 260 ° C., which is about 20 ° C. higher than conventional. Due to changes in solder processing temperature for lead-free soldering, defects at the area mounting type semiconductor device due to peeling at the interface between the epoxy resin encapsulant and the organic substrate and peeling at the interface between the semiconductor element and the resin paste Problems have arisen. For this reason, various improvements have been advanced with the aim of improving solder resistance during surface mounting at 260 ° C. (see, for example, Patent Document 1). Neither of these is a complete solution, and further improvements are desired.

Furthermore, in order to achieve both a reduction in package size and high integration of semiconductor elements, semiconductor elements having a large area tend to be mounted on a narrow semiconductor element mounting surface. For this reason, the distance between the fillet and the gold wire bonding pad becomes very short, and the resin bleed of the die attach paste causes a problem of ground bond (wire bond from the semiconductor element to the die pad), which is a problem.
JP 2000-273326 A

  The present invention provides a resin composition having a sufficiently low stress property and exhibiting good adhesion and bleeding properties, and a semiconductor device having excellent reliability by using the resin composition as a die attach material for semiconductors. It is to be. In particular, it has excellent adhesion to an organic substrate.

Such an object is achieved by the present invention described in the following [1] to [5].
[1] (A) a polyalkylene oxide skeleton bismaleimide compound, (B) a compound having at least one functional group represented by the general formula (1) and at least one carboxy group, and (C) the general formula ( 1. A resin composition comprising as an essential component a compound having at least one functional group represented by 1) and having at least one hydroxyl group.

Ｒ¹は、水素原子又はメチル基である。

R ¹ is a hydrogen atom or a methyl group.

[2] The resin composition according to item [1], further comprising (D) an epoxy resin.
[3] The resin composition according to item [2], further comprising (E) an epoxy resin curing agent.
[4] The resin composition according to item [2] or [3], wherein the (D) epoxy resin is liquid at room temperature.
[5] A semiconductor device manufactured using the resin composition according to any one of [1] to [4] as a die attach material.

  According to the present invention, it is possible to provide a resin composition excellent in low-stress property, adhesiveness, and bleed property, and a semiconductor device excellent in reliability using the resin composition as a die attach material for a semiconductor. In particular, it has excellent adhesion to an organic substrate.

The present invention provides a polyalkylene oxide skeleton bismaleimide compound, a compound having at least one functional group represented by the general formula (1) and at least one carboxy group, and a functional group represented by the general formula (1). By using a compound having at least one and having at least one hydroxyl group, a resin composition excellent in low-stress property, adhesiveness, and bleed property, and reliability using the resin composition as a die attach material for semiconductors An excellent semiconductor device is provided.
Hereinafter, the present invention will be described in detail.

In the present invention, the (A) polyalkylene oxide skeleton bismaleimide compound is used because it exhibits good fluidity and good adhesiveness even when a filler is blended. Having a maleimide group as a functional group, especially when used together with a thermal radical initiator, it exhibits good reactivity under heating and, for example, on the hard-to-adhesive metal surface such as silver plating or Ni-Pd plating due to the polarity of the imide ring. On the other hand, it exhibits good adhesion to an organic substrate. In addition, it has two functional groups in one molecule, but this is not sufficient for the expected adhesion improvement effect in the case of one function, and in the case of three or more functions, the molecular weight is increased, resulting in an increase in viscosity and resin. This leads to higher viscosity of the composition, and further increases the degree of crosslinking after curing, leading to higher elastic modulus. Here, as a bifunctional maleimide compound, those using an aromatic amine as a raw material are well known. However, since an aromatic maleimide compound has strong crystallinity, it is difficult to obtain a liquid at room temperature. Such maleimide compounds are soluble in high-boiling polar solvents such as dimethylformamide and N-methylpyrrolidone. However, when such a solvent is used, voids are not formed during heat curing of the resin composition. It occurs and cannot be used. Since the compound (A) is liquid at room temperature, it is not necessary to use a solvent, and even when dilution is required, it exhibits good affinity with a generally used liquid vinyl compound. Dilution with is possible. Among them, a vinyl compound having a (meth) acryloyl group can be suitably used as a diluent because it can be copolymerized with the compound (A). Furthermore, it is preferable that the structure does not contain an aromatic ring, which greatly contributes to lowering the elastic modulus of the cured product. The number of alkylene oxide units in the main chain is preferably n = 10 or less. When n = 10 or more, the viscosity becomes too high, which is not preferable for practical use.
As such a compound (A), a compound having an amide group and a carboxy group and having a hydrocarbon group having 1 to 10 carbon atoms between the compound having an amide group and a carboxy group (glycine, alanine, aminocaproic acid, etc.) ) And maleic anhydride or a derivative thereof are synthesized to synthesize maleimidated amino acids, which can be obtained by reacting them with alkylene oxide diol, polyalkylene ester diol or the like. For example, polytetramethylene glycol-di (2-maleimide acetate) and the like can be mentioned.

In the present invention, a compound (B) having at least one functional group represented by the general formula (1) and having at least one carboxy group is used. This is because it is useful as a reactive diluent and can prevent a decrease in adhesive strength after moisture absorption.
Since the functional group represented by the general formula (1) of the compound (B) has a carbon-carbon double bond as a reactive site, it can be copolymerized with the compound (A) and has high reactivity. It is difficult to volatilize during heating or subsequent wire bonding, and the generation of voids can be suppressed.
When a non-reactive diluent is used, it does not react with other resin composition components by heating, so the diluent volatilizes during heating at the time of curing or subsequent heating at the time of wire bonding. Or the components adhere to the semiconductor element or die pad, often causing wire bond failure, or reducing the adhesion of the sealing material to the die pad and causing peeling or cracking. Therefore, it is not preferable.
Evaluation of solder resistance is usually performed by exposing the package to high temperature and high humidity before reflow and in a state where the package contains sufficient moisture, so the die attach material is exposed to high temperature and high humidity compared to immediately after curing. Although the adhesiveness is significantly lowered, the decrease in adhesion after moisture absorption can be minimized by having a carboxy group.
Examples of the compound (B) include 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, and the like. .

In the present invention, the compound (C) having at least one functional group represented by the general formula (1) and having at least one hydroxyl group is used. This is because it is useful as a reactive diluent and can exhibit excellent bleeding properties.
Since the functional group represented by the general formula (1) of the compound (C) has a carbon-carbon double bond as a reactive site, it can be copolymerized with the compound (A) and has high reactivity. It is difficult to volatilize during heating or subsequent wire bonding, and the generation of voids can be suppressed.
When a non-reactive diluent is used, it does not react with other resin composition components by heating, so the diluent volatilizes during heating at the time of curing or subsequent heating at the time of wire bonding. Or the components adhere to the semiconductor element or die pad, often causing wire bond failure, or reducing the adhesion of the sealing material to the die pad and causing peeling or cracking. Therefore, it is not preferable.
Moreover, it becomes possible to show the outstanding bleeding property by having a hydroxyl group. Here, bleed refers to a phenomenon in which the resin component of the resin composition spreads on the adherend surface when the resin composition is applied to an adherend such as a lead frame or an organic substrate, and often the bleed is grounded. This is an undesired phenomenon because it causes a bond (wire bond from the semiconductor element to the die pad) failure, or reduces the adhesive force of the sealing material to the die pad, causing peeling and cracking. Here, the excellent bleedability means that bleed does not easily occur, that is, the above-described problem hardly occurs.
Examples of the compound (C) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2 -Acryloyloxy-2-hydroxyethylphthalic acid, glycerol di (meth) acrylate, 1, 4- cyclohexane dimethanol monoacrylate etc. are mentioned.

  By using the compound (B) and the compound (C) in combination, it becomes possible for the first time to achieve both excellent adhesiveness and bleeding property. The compounding ratio of the compound (B) and the compound (C) is not particularly limited, but the compound (B) / compound (C) is preferably 0.05 or more and less than 20. More preferably, it is 0.1 or more and less than 10, and further preferably 0.3 or more and less than 5. If it is less than the lower limit, the effect of the adhesiveness of the compound (B) is not preferable, and if it is more than the upper limit, the effect of the bleeding property of the compound (C) is difficult to be obtained.

  Examples of the epoxy resin (D) used in the present invention include glycidyl etherified bisphenols such as bisphenol A and bisphenol F, glycidyl etherified phenols such as phenol novolac and cresol novolac, epoxides of aminophenols, aliphatic Examples thereof include glycidyl ethers, glycidyl ethers that have been converted to an aliphatic ring by hydrogenation, and alicyclic epoxy compounds. In particular, it is preferable to use an epoxy resin that is liquid at room temperature so that the viscosity of the die attach paste does not become too high. Low-viscosity aliphatic glycidyl ethers, glycidyl ethers that are converted to aliphatic rings by hydrogenation, and alicyclic epoxies Compound etc. are mentioned.

  Examples of the epoxy resin curing agent (E) used in the present invention include aliphatic (poly) amines, aromatic (poly) amines, imidazoles, acid anhydrides, phenolic compounds such as phenol novolac, bisphenol A and bisphenol F, and polyamide resins. , Polysulfide resin, dicyandiamide and the like. In particular, it is preferable to use one or more selected from imidazoles, phenolic compounds, and dicyandiamide for the purpose of achieving both storage stability and reactivity.

  It is also possible to use a thermal radical initiator as a reaction initiator of the compound (A), the compound (B) and the compound (C). Although it is not particularly limited as long as it is normally used as a thermal radical polymerization initiator, it is desirable that a rapid heating test (decomposition start temperature when a sample is placed on an electric heating plate and heated at 4 ° C./min. In which the decomposition temperature is 40 to 140 ° C. If the decomposition temperature is less than 40 ° C., the preservability of the resin composition at normal temperature deteriorates, and if it exceeds 140 ° C., the curing time becomes extremely long, which is not preferable.

  Specific examples of the thermal radical polymerization initiator satisfying this include methyl ethyl ketone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis (t-butylperoxy) 3, 3, 5 -Trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) ) Cyclohexane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododecane, n-butyl 4,4-bis (t- Butyl peroxy) valerate, 2,2-bis (t-butylperoxy) Tan, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, t-butyl hydroperoxide, P-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, t -Hexyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, α, α'-bis (t-butylperoxy) diisopropylbenzene, t-butyl Cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide , Octanoyl peroxide, lauroyl peroxide, cinnamic acid peroxide m-toluoyl peroxide, benzoyl peroxide, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexyl peroxide Carbonate, di-sec-butylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, α, α′-bis (neo) Decanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecano Eate, t-hexyl par Xineodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylper) Oxy) hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2- Ethyl hexanoate, t-butyl peroxy-2-ethyl hexanoate, t-butyl peroxyisobutyrate, t-butyl peroxymaleic acid, t-butyl peroxylaurate, t-butyl peroxy- 3,5,5-trimethylhexanoate, t-butylperoxyisopropyl monocarbonate, -Butylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxy-m -Toluoyl benzoate, t-butyl peroxybenzoate, bis (t-butylperoxy) isophthalate, t-butylperoxyallyl monocarbonate, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl ) Benzophenone and the like can be mentioned, but these can be used alone or in combination of two or more in order to control curability. Although not necessarily limited, it is preferable to contain 0.001 to 3weight% in a resin composition.

  Since the resin composition of the present invention is usually used under illumination such as a fluorescent lamp, if a photopolymerization initiator is contained, an increase in viscosity is observed due to a reaction during use. Cannot be contained. “Substantially” means that a small amount of the photopolymerization initiator may be present to such an extent that no increase in viscosity is observed, and it is preferably not contained.

  In the present invention, various fillers can be used. Since the field of use is semiconductor applications, the amount of ionic impurities such as halogen ions and alkali metal ions is preferably 10 ppm or less. Depending on the required properties, metallic fillers such as silver, gold, copper and nickel, inorganic fillers such as silica, aluminum nitride and boron nitride, or organic fillers such as baked phenol particles and polyimide particles can be used alone or in combination. As the shape, flaky, fibrous, resinous, indeterminate or spherical shapes can be used alone or in combination. Further, the average particle size is preferably 2 to 10 μm and the maximum particle size is preferably about 50 μm, and a relatively fine filler and a coarse filler may be mixed and used.

  In the present invention, a silane coupling agent can be used for the purpose of obtaining good adhesion. In particular, when the silane coupling agent having an S—S bond is used together with silver powder, it not only improves the adhesion to the adherend, but also reacts with the silver powder, so that the cohesive strength of the cured resin composition is also improved, and thus particularly excellent adhesion. Can be obtained, which is preferable. Examples of the silane coupling agent having such an S—S bond include bis (trimethoxysilylpropyl) tetrasulfide, bis (triethoxysilylpropyl) tetrasulfide, bis (tributoxysilylpropyl) tetrasulfide, and bis (dimethoxymethyl). Silylpropyl) tetrasulfide, bis (diethoxymethylsilylpropyl) tetrasulfide, bis (dibutoxymethylsilylpropyl) tetrasulfide, bis (trimethoxysilylpropyl) disulfide, bis (triethoxysilylpropyl) disulfide, bis (tributoxy) Silylpropyl) disulfide, bis (dimethoxymethylsilylpropyl) disulfide, bis (diethoxymethylsilylpropyl) disulfide, bis (dibutoxymethylsilylpropyl) Such as disulfide, and the like. Further, it is more preferable to use a silane coupling agent having a glycidyl group together with a silane coupling agent having an S—S bond. Examples of the silane coupling agent having a glycidyl group include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycid Examples include xylpropyltriethoxysilane.

In the resin composition of the present invention, additives such as an antifoaming agent, a surfactant, various polymerization inhibitors, and antioxidants can be used as necessary.
The resin composition of the present invention can be produced, for example, by premixing the components, kneading using three rolls, and degassing under vacuum.
As a method of manufacturing a semiconductor device using the resin composition of the present invention, a known method can be used. For example, using a commercially available die bonder, a resin composition is dispense-applied to a predetermined part of a lead frame or an organic substrate, and then a semiconductor element (hereinafter sometimes referred to as a chip) is mounted and heat-cured. Thereafter, wire bonding is performed, and a semiconductor device is manufactured by transfer molding using an epoxy resin.

[Example 1]
As compound (A), polytetramethylene glycol-di (2-maleimide acetate) (Dainippon Ink & Chemicals, LumiCure MIA-200, hereinafter referred to as MIA-200) is used. -Methacryloyloxyethyl succinic acid (manufactured by Kyoeisha Chemical Co., Ltd., light ester HO-MS, hereinafter HO-MS), and as compound (C), glycerin dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., light ester G-101P) G-101P), as thermal radical initiator (D), dicumyl peroxide (manufactured by NOF Corporation, Park Mill D, decomposition temperature in rapid heating test: 126 ° C., hereinafter initiator), silane coupling agent Having a glycidyl group (Shin-Etsu Chemical Co., Ltd., KBM-403E, hereinafter KBM-403E), The powder was used the average particle size of 8 [mu] m, a flaky silver powder of the maximum particle size of 30 [mu] m (hereinafter silver).
The above components were blended as shown in Table 1, kneaded using three rolls, and defoamed to obtain a resin composition. The blending ratio is parts by weight.

[Examples 2 and 3]
Components used in Examples other than Example 1 are epoxy resin (D), diglycidyl bisphenol A obtained by reaction of bisphenol A and epichlorohydrin (epoxy equivalent 180, liquid at room temperature, hereinafter bis A epoxy), epoxy resin curing As the agent (E), 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine (manufactured by Shikoku Chemicals Co., Ltd., Curezol 2MZ-A, hereinafter 2MZ-A) ) And dicyandiamide (hereinafter referred to as DDA), which were blended as shown in Table 1, and a resin composition was obtained in the same manner as in Example 1.
The obtained resin composition was evaluated by the following methods. The evaluation results are shown in Table 1.

[Comparative Examples 1-5]
Polytetramethylene glycol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-PTMG-65, hereinafter A-PTMG-65), 1,6-hexanediol dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., light ester) 1,6HX, hereinafter 1,6HX), cresyl glycidyl ether (epoxy equivalent 185, hereinafter CGE), bisphenol A (manufactured by Dainippon Ink & Chemicals, Inc., DIC-BPF, hereinafter BPF)
The resin composition was obtained in the same manner as in Examples 1 and 2 by blending at the ratio shown in Table 1.
The obtained resin composition was evaluated by the following methods. The evaluation results are shown in Table 1.

Evaluation Method / Adhesive Strength: Using the resin composition shown in Table 1, a 6 × 6 mm silicon chip was formed into a circuit using an organic substrate (substrate: ELC-4781 manufactured by Sumitomo Bakelite Co., Ltd., solder resist: Taiyo And coated with PSR-4000-AUS308 manufactured by Ink Manufacturing Co., Ltd.) and cured in an oven at 175 ° C. for 15 minutes. After curing and after moisture absorption treatment (85 ° C., 85%, 72 hours), the hot die shear strength at 260 ° C. was measured using an automatic adhesive force measuring apparatus. The case where the die shear strength when heated at 260 ° C. was 50 N / chip or more was regarded as acceptable. The unit of adhesive strength is N / chip.
-Adhesive strength deterioration rate after moisture absorption: (Adhesive strength after curing-Adhesive strength after moisture absorption) / Adhesive strength after curing x 100, and a case of 50% or less was accepted. The unit is%.
-Elastic modulus of cured resin: After applying the resin composition described in Table 1 on a Teflon (registered trademark) sheet to a width of 4 mm, a length of about 50 mm, and a thickness of 200 μm and curing in a 175 ° C. oven for 15 minutes, Using a viscoelasticity measuring device, the tensile viscoelasticity was measured at a test length of 20 mm, a heating rate of 5 ° C / minute from -100 ° C to 300 ° C at 10 Hz, and the storage elastic modulus at room temperature (25 ° C) and 250 ° C. Asked.
Bleed: Using the resin composition shown in Table 1, a 6 × 6 mm silicon chip was mounted on a silver spot-plated copper frame (with silver plating on the die pad portion) and cured in an oven at 175 ° C. for 15 minutes. The bleed of the cured product was observed with an optical microscope, and the longest length of each test piece was taken as the bleed. A bleed having a length of 50 μm or less was accepted. The unit of bleed is μm.
-Reflow resistance: Using the resin composition shown in Table 1, a silicon chip was mounted on the following substrate, and cured and adhered for 15 minutes at 175 ° C. This was sealed using a sealing material (Sumicon EME-G770 type LE, manufactured by Sumitomo Bakelite Co., Ltd.) to prepare a package. After moisture absorption treatment at 85 ° C. and relative humidity 60% for 168 hours, IR reflow treatment (260 ° C., 10 seconds, 3 times reflow) was performed. The degree of peeling of the treated package was measured with an ultrasonic flaw detector (transmission type). The case where the peeling area of the whole package was less than 10% was regarded as acceptable. The unit of the peeled area is%.
Package: BGA (35 x 35 mm)
Substrate: A circuit was formed using ELC-4781 manufactured by Sumitomo Bakelite Co., Ltd., and coated with the following solder resist.
Solder resist: PSR-4000-AUS308 manufactured by Taiyo Ink Manufacturing Co., Ltd.
Chip size: 10x10mm
Curing conditions for resin composition: 175 ° C. in oven for 15 minutes

  Since the resin composition of the present invention exhibits good low-stress properties, good adhesiveness, and bleed properties, it can be suitably used for bonding semiconductor elements that require these simultaneously.

Claims (5)

(A) a polyalkylene oxide skeleton bismaleimide compound, (B) a compound having at least one functional group represented by the general formula (1) and at least one carboxy group, and (C) a general formula (1) A resin composition comprising as an essential component a compound having at least one functional group and at least one hydroxyl group ,
The compounding ratio of the compound (B) and the compound (C) is such that the compound (B) / compound (C) is 0.05 or more and less than 20 in weight ratio .

R ¹ is a hydrogen atom or a methyl group.
The resin composition according to claim 1, further comprising (D) an epoxy resin. The resin composition according to claim 2, further comprising (E) an epoxy resin curing agent. The resin composition according to claim 2 or 3, wherein the (D) epoxy resin is liquid at room temperature. A semiconductor device manufactured using the resin composition according to claim 1 as a die attach material.