JPS626573B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an epoxy-silicone resin composition, and in particular, it is an object of the present invention to provide a resin composition that has low moisture permeability and can prevent corrosion and disconnection of aluminum lead wires in semiconductor devices as much as possible. Conventionally, as this type of thermosetting resin composition for semiconductor encapsulation, for example, (1)

[Formula] Obtained by reacting a bond-containing organosilicon compound and an epoxy bond-containing organic compound in the presence of a specific aluminum compound.

[Formula] Silicone resin having a bond (see JP-A-51-118728), (2)

[Formula] Bond-containing organosilicon compound, epoxy bond-containing organic compound, aluminum compound, and

[Formula] Compositions consisting of bond-containing organosilicon compounds (see Japanese Patent Publication No. 53-29720) are known, and cured products obtained from these compositions have electrical properties, especially electrical properties at high temperatures, that are better than conventional ones. It is much superior to those obtained from epoxy resin compositions, has good moisture resistance (low water absorption), and even if it comes into contact with moisture, the electrical properties of the cured product are almost the same as general silicone resins. It has the feature of having a value of . However, the above-mentioned resins or compositions have the disadvantage that their moisture resistance under high temperature and high pressure conditions is inferior to that of conventional epoxy resins. That is, when a semiconductor device sealed with the resin or composition is subjected to a physical property test under pressure vacuum conditions (for example, at a temperature of 121°C and a pressure of 2.2 atm), corrosion of the aluminum lead wire of the device occurs from the initial stage. Despite its excellent physical properties, it is difficult to apply it successfully as a sealing material for electrical or electronic devices such as integrated circuits. The present invention relates to a novel epoxy-silicone resin composition that solves the conventional disadvantages as described above, and is composed of (a) (A) a phenol novolak or Cresol novolac epoxy resin 70-90% by weight, (B)(i) General formula (R ¹ ) _n Si(OH) _o …………() (In the formula, R ¹ is substituted or unsubstituted monovalent carbonized (ii) an organosilanol represented by the general formula (HO) _p (R ² ) _q SiQSi(R ² ) _q (OH ) _p
………() (In the formula, R ² is a substituted or unsubstituted monovalent hydrocarbon group, Q is an aromatic divalent hydrocarbon group, p
is 1 or 2, q is 1 or 2, but p+
q is 3) and (iii) the ratio ^{R 3 /} Si (where R ³ is a substituted or unsubstituted monovalent hydrocarbon group) is 1.05 to 1.6, and the ratio Ph/Si of the silicon atom (Si) to the phenyl group (Ph) directly bonded to it is 0.2 to 0.99, The content of hydroxyl groups directly bonded to silicon atoms is 8 to 10% by weight, and the softening temperature is 50 to 50%.
It consists of a phenyl group-containing organopolysiloxane resin at 120°C, and the mixing ratios of these are (i) 0 to 50% by weight, (ii) 50 to 95% by weight, and (iii) 0 to 50% by weight, and in this mixture. Organosilicon compounds with a silicon-bonded hydroxyl group content of 10% by weight or more
100 parts by weight of a mixture consisting of 30-10% by weight, (b) 100-550 parts by weight of a filler, and (c) 0.05-5 parts by weight of a curing catalyst. In general, the water vapor permeability of a sealing resin varies depending on the type of resin that is its main component, and among these resins, silicone resin has a very large value, and silicone resin has a very high value in epoxy-silicone composite materials. Naturally, the higher the usage rate, the higher the water vapor permeability of the resulting molded article. In the semiconductor industry, one method for measuring the moisture resistance characteristics of integrated circuits is to corrode the aluminum lead wires of devices under high temperature, high pressure, and high humidity. For example, (1) impurities present in the resin, (2) ingress of moisture due to insufficient adhesion at the interface between the sealing resin and the lead wire, or (3) penetration of the sealing resin. Corrosion caused by moisture entering the area is considered to be the cause. Concerning impurities in the sealing resin, hydrolyzable chlorine atoms and amine-based curing catalysts present in the epoxy resin pose a problem.
Since silicone resins do not contain any amine compounds, their impurity content is extremely low compared to epoxy resins. In addition, to prevent moisture from entering from the interface between the sealing resin and the lead wire, the resin

[Formula] This can be achieved to some extent by adding silicone oil containing a bond (see Japanese Patent Publication No. 53-29720) or by selectively using an arbitrary release agent; However, it is difficult to obtain sufficiently satisfactory results, and corrosion tests on aluminum lead wires have the disadvantage that corrosion tends to occur from the initial stage. However, according to the epoxy-silicone resin composition of the present invention, the original purpose of encapsulating semiconductor devices with resin can be satisfactorily achieved, and since the composition has extremely low moisture permeability, the above-mentioned corrosion problem has been greatly improved. be done. Hereinafter, the epoxy-silicone resin composition according to the present invention will be explained in detail. The phenol novolac or cresol novolac epoxy resin as the component (A) constituting the resin composition of the present invention is conventionally known as a thermosetting resin, and commonly commercially available ones are used in the present invention. be done. However, from the purpose of the present invention to obtain a product with low moisture permeability, the content of hydrolyzable chlorine atoms as this component (A) should be as low as possible (2000 ppm or less, especially 1000 ppm or less).
In addition, component (A) must have a free chlorine content of 10 ppm or less and a total content of sodium and potassium atoms.
It is desirable that the content is 10ppm or less. If necessary, an alicyclic epoxy compound may be used in combination with the epoxy resin as component (A). Next, the component (B) used in combination with the component (A) above consists of the components (i), (ii), and (iii) described above; It must be a mixture of i) 0 to 50% by weight, (ii) 50 to 95% by weight, and (iii) 0 to 50% by weight, which also means that the hydroxyl group bonded to silicon atoms must be 10% by weight or less. If the lead frame is cut after being molded into a semiconductor device, cracks may occur in the resin or peeling may occur at the interface between the resin and the lead. It is necessary that the hydroxyl group content is 10% by weight or more so that the hardness after molding is 70 or more on Barcoll hardness. In this general formula () for component (i),
R ¹ is a methyl group, an ethyl group, a propyl group,
Alkyl groups such as butyl groups, alkenyl groups such as vinyl groups and allyl groups, allyl groups such as phenyl groups, cycloalkyl groups such as cyclopentyl groups and cyclohexyl groups, or hydrogen atoms of these groups partially contain chlorine atoms, etc. Examples include groups substituted with halogen atoms. In addition, from the viewpoint of achieving the object of the present invention satisfactorily, R ¹ is preferably a phenyl group (when m is 2, at least one phenyl group). m, n and m+n in formula () are as described above. As the organosilanol represented by the above general formula (), for example, (C ₆ H ₅ )・(CH ₃ )Si
(OH) ₂ , (C ₆ H ₅ ) ₂ Si (OH) ₂ , (C ₆ H ₅ )・(C ₂ H ₅ )Si
Examples include (OH) ₂ or (C ₆ H ₅ )Si(OH) ₃ . In addition, the substituted or unsubstituted monovalent hydrocarbon group represented by R ² in the general formula () in component (ii) includes alkyl groups such as methyl group, ethyl group, propyl group, butyl group, vinyl group, Examples include alkenyl groups such as allyl groups, allyl groups such as phenyl groups, cycloalkyl groups such as cyclopentyl groups and cyclohexyl groups, and groups in which the hydrogen atoms of these groups are partially substituted with halogen atoms such as chlorine atoms. Examples of the aromatic divalent hydrocarbon group represented by Q include arylene groups such as phenylene groups, alkalylene groups such as phenethylene groups, and halogen atoms in which some or all of the hydrogen atoms of these groups are Examples include groups substituted with . p, q and p+q are as described above. Examples of the disylhydrocarbene compound represented by the general formula () include the following compounds. Furthermore, R ³ in the phenyl group-containing organopolysiloxane resin, which is the component (iii), represents a substituted or unsubstituted monovalent hydrocarbon group, and examples thereof include the same groups as those exemplified for R ² above. be able to. This siloxane resin has a ratio (R ³ /Si) of 1.05 to 1.6 between silicon atoms (Si) and monovalent hydrocarbon groups (R ³ ) directly bonded to silicon atoms (Si), and It is required that the ratio (Ph/Si) to the bonded phenyl group (Ph) is 0.2 to 0.99, and that the amount of hydroxyl groups directly bonded to silicon atoms is in the range of 8 to 10% by weight. In addition, this siloxane resin has a softening temperature of 50~
120°C, preferably 65 to 85°C, but siloxane resins with a softening temperature of 50°C or lower tend to soften during handling, resulting in significantly poor workability; Those above have high melt viscosity and poor fluidity. This phenyl group _- containing organopolysiloxane resin itself has been known for a long time, and the siloxane units constituting this siloxane resin include, for example, CH ₃ SiO _1.5 , C ₂ H _{5 SiO 1.5 ,
C3H7SiO1.5 , CH2 = CHSiO1.5 , C6H5SiO1.5 , _ _ _}
Examples include Cl ₃ CH ₂ CH _{2 SiO 1.5} , but
As long as the R ³ /Si ratio, Ph / Si ratio, hydroxyl group content and softening temperature are within the above ranges (CH ₃ ) ₂ SiO,
(C ₂ H ₅ ) ₂ SiO, (C ₃ H ₇ ) ₂ SiO, (C ₆ H ₅ ) ₂ SiO, (CH ₂
= CH) ₂ SiO, (CH ₃ ) (CH ₂ = CH) SiO, (CH ₃ )
diorganosiloxane units such as ( _{C6H5 )} SiO,
It may contain SiO ₂ and further an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group. This siloxane resin is made by adding one or more corresponding organohalosilanes or alkoxysilanes to the final siloxane resin.
It is obtained by carrying out a hydrolysis/condensation reaction according to a conventional method so that the R ³ /Si ratio, Ph/Si ratio, etc. are within the above ranges. Component (A) in the present invention consists of the above-mentioned epoxy resin (A) and organosilicon compound (B), but the blending ratio of both of them depends on the final cured sealing resin. Water vapor transmission rate is 3.5g/
24hr・m ² (Measurement conditions: Cured resin thickness 1mm, temperature 60
℃ and relative humidity of 95%) or less, it is necessary to minimize the amount of the organosilicon compound (B), which has a relatively high water vapor permeability, as much as possible. Generally, the former (epoxy resin) is 70 to 90% by weight
In contrast, the latter (organosilicon compound) is required to be 30 to 10% by weight, but good curing is achieved when the proportion of organosilicon compound used is 10% by weight or less. can't do it on the other hand 30
This is because if the amount exceeds % by weight, it becomes difficult to obtain a sealing resin having low moisture permeability, which is the object of the present invention. In addition, when using the organosilicon compound (B) component, it is necessary to mix (i), (ii), and (iii) in the above mixing ratio, but these should not fall within this mixing ratio range. Needless to say, they may be used in any combination depending on the type of epoxy resin. As the filler (component (b)), various materials such as fine powder and fibrous materials conventionally used in this type of composition can be used, including fused silica, crystalline silica, and glass. Powder, glass fiber, clay, talc, mica, asbestos, zinc oxide,
Examples include magnesia, aluminum silicate, zirconium silicate, alumina, and fumed silica. Among these, preferred fillers are fused silica, crystalline silica, glass powder, or glass fiber. The preferred blending amount of these fillers varies depending on the specific type, but in general, the amount of the above-mentioned (a) component is
The amount is approximately 100 to 550 parts by weight, preferably 300 to 500 parts by weight per 100 parts by weight. Furthermore, as the curing catalyst which is component (iii) in the present invention, aluminum alcoholate, aluminum acylate, aluminosiloxane compound,
Examples include aluminum chelate compounds. It is sufficient that the amount of component (iii) used is in the range of 0.05 to 5 parts by weight (in terms of Al) per 100 parts by weight of component (a). Furthermore, the composition of the present invention may contain waxes such as carnauba wax, op-wax, and polyethylene wax, zinc stearate, cobalt stearate, etc. to facilitate release from the mold, if necessary. Stearic acid compound, dimethylpolysiloxane, methylphenylpolysiloxane,
Addition of mold release agents such as organopolysiloxane compounds such as methylhydrodiene polysiloxane, plasticizers, flame retardants such as bromine atom-containing epoxy resins, flame retardant aids such as antimony compounds, pigments such as titanium oxide and carbon black, etc. There is no problem in mixing them. The composition according to the present invention can be prepared by employing various methods, including, for example, preparing (a) to (c) in advance.
After the ingredients are pulverized, this is mixed using a Henschel mixer, etc., and then kneaded with a kneader. After kneading the components (a) and (b) with two heated rolls, Examples include a method in which the component (c) is uniformly added and mixed, and a granular semiconductor encapsulating resin can be obtained by pulverizing the composition obtained in this way. The sealing resin obtained as above has a water vapor permeability of 3.5g/24hr・m ² (measurement conditions, same as above)
The results are as follows, and integrated circuits sealed using this material show no initial failure in aluminum electrode corrosion tests under high temperature, high pressure, and high humidity. Next, examples of the present invention will be given. Comparative Example 1 CH ₃ SiO _1.5 40 mol%, ( _{CH 3} ) ₂ SiO 10 mol%,
_C6H5SiO1.5 40 _mol % and _{( C6H5} ) _{2SiO10 mol %}
silicone resin (chlorine content 5ppm) with a hydroxyl group content of 8% by weight and a softening temperature of 70°C.
g, epoxy cresol novolak resin (epoxy equivalent weight 225, hydrolyzable chlorine atom content
1100ppm) 64.5g, bromine atom-containing epoxy resin (epoxy equivalent: 340) 5.5g, fused silica 277g,
A mixture consisting of 2.5 g of Sb ₂ O ₃ , 1 g of carnauba wax, and 0.5 g of carbon black was kneaded with two heated rolls, then 0.4 g of aluminum benzoate was added as a catalyst, and kneaded for 1.5 minutes to prepare an epoxy-silicone resin. (hereinafter referred to as molding material A). Comparative Example 2 An epoxy-silicone resin was prepared in the same manner as in Comparative Example 1, except that the amount of silicone resin used was 20 g and the amount of epoxy cresol novolak resin was 74.5 g. Hereinafter, this will be referred to as molding material B). Comparative Example 3 An epoxy-silicone resin was prepared in the same manner as in Example 1, except that the amount of silicone resin used was 50 g and the amount of epoxy cresol novolak resin was 44.5 g. Hereinafter, this will be referred to as molding material C). Example 1 70 g of epoxy novolac resin (hydrolyzable chlorine atom content 1400 ppm, epoxy equivalent 210),

[Formula] 18g, diphenylsilanediol 12g, fused silica 270g and carnauba wax 0.9g are thoroughly kneaded with two rolls heated to 80℃, then 0.6g of aluminum benzoate is added as a catalyst and kneaded for 2 minutes. epoxy
A silicone resin was prepared (hereinafter referred to as molding material D). Comparative Example 4 Same silicone resin as used in Comparative Example 1
30g, bromine atom-containing epoxy resin 5.5g, fused silica 230g, glass fiber 40g, Sb ₂ O ₃ 2.5g, carnauba wax 1.0g, aluminum benzoate 0.4
g, epoxy cresol novolak resin (hydrolyzable chlorine atom content 1100 ppm, epoxy equivalent 225) and epibis type epoxy resin (hydrolyzable chlorine atom content 225) in the proportions shown in Table 1 below.
800 ppm, epoxy equivalent: 450) were uniformly mixed to prepare three types of epoxy-silicone resins (molding materials E, F and G).

[Table] Experiment 1 The curability, water vapor permeability, and failure rate of aluminum electrode breakage were investigated as follows for the molding materials A to G obtained above, and it was found that molding materials A,
Type B has low water vapor permeability, but curability is 0~
20 (thermal curing), which was insufficient, molding material E had poor moisture resistance, and molding material F and G had even lower moisture resistance, but the physical property values of these are shown in the table below. The results shown in 2 were obtained. Curability: Curability was defined as Percoll hardness after molding at a temperature of 175°C for 2 minutes. Measurement of water vapor permeability; Molding material was molded at 175℃ and molding pressure 70Kg/
cm ² , molded in 3 minutes to form a 1 mm thick disk, post-cured at 180℃ for 4 hours, and then molded in an atmosphere of 60℃ and 95% relative humidity according to JIS Z 0208. Transmittance was measured. Measurement of aluminum electrode corrosion; Die bonding the aluminum corrosion measurement element manufactured by the following process to the frame of a 14-pin IC,
After wire bonding, resin sealing was performed using molding material, the lead terminals were cut, and the temperature was 121°C.
It was left in a steam atmosphere at 2.2 atmospheres, and disconnection was detected after a predetermined period of time. The molding conditions for resin sealing are a molding temperature of 175
℃, a molding pressure of 70 kg/cm ² , and a molding time of 2 minutes. Furthermore, all molded products were post-cured at 180°C for 4 hours. Manufacturing process of aluminum corrosion measurement element Silicon wafer ↓ SiO ₂ film creation ↓ Single-sided SiO ₂ film etching ↓ Aluminum vapor deposition film creation ↓ Photoresist, development, baking ↓ Etching water washing treatment ↓ Annealing ↓ Scribing

【table】

[Table] Comparative Example 5 Epoxy-silicone resins were prepared by treating the components shown in Table 3 below in the same manner as in Comparative Example 1 (molding materials H to K). However, the silicone resin consists of 40 mol% CH ₃ SiO _{1.5 ,} 10 mol% (CH ₃ ) ₂ SiO, ₄₀ mol% C ₆ H ₅ SiO _1.5 and 10 mol% (C ₆ H ₅ ) ₂ SiO. be.

[Table] Comparative Example 6 A molding material L was prepared using the same composition as in Example 1 except that 20 g of diphenylsilane diol was used instead of the silicone resin in Example 3. Example 2 Except for using 5 g of silicone resin and 15 g of diphenylsilanediol used in Comparative Example 1,
A molding material M having the same composition as in Example 1 was treated in the same manner as in Example 1 to prepare a molding material M. Experiment 2 Each molding material H, I, J, K, L prepared above
When molding materials H and M were molded under the following conditions and their moldability was investigated, it was found that the molding material H had a heat hardening rate of 30
~40, which is not at a practical level, and although molding material L has sufficient curing properties, it was found that it lacked fluidity due to high reactivity.The physical properties of these are shown in Table 4 below. The results shown in were obtained. Molding; transfer molding,
Molding pressure: 70Kg/ ^cm2 , hardness measurement: After molding at 175°C for 2 minutes, hot hardness when the mold is dismantled (hardness tester, Barcall hardness tester JYZJ-935).

【table】

[Table] Example 3 The amount formula shown in Table 5 was applied to an epoxy cresol novolak resin with a hydrolyzable chlorine atom content of 700 ppm and an epoxy equivalent of 220.

Disylhydrocarbene compound (abbreviated as silicone 1) represented by [Formula], formula

Silicone compound represented by the formula (abbreviated as silicone 2), CH ₃ SiO _{1.5 units} 40 mol%, (CH ₃ ) ₂ SiO units 10 mol%, C ₆ H ₅ SiO _{1.5 units} 40
A silicone resin (abbreviated as silicone 3) consisting of 10 mol% of (C ₆ H ₅ ) ₂ SiO units and a silicon-bonded hydroxyl group content of 10% by weight, fused silica, and carnauba wax is added. After thoroughly kneading with two heated rolls, aluminum benzoate as a catalyst was added and kneaded for 2 minutes to make molding material N-Q, and the water vapor permeability and curing properties of the molded products made from this were examined. The results shown in Table 5 were obtained.

【table】

Claims (1)

[Claims] 1 (A) (A) The hydrolyzable chlorine atom content is
Phenol novolac or cresol novolac epoxy resin with less than 2000ppm
70-90% by weight, (B)(i) General formula (R ¹ ) _n Si(OH) _o (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, m is 1 or 2, n is 2 or 3, where m+n is 4), (ii) general formula (HO) _p (R ² ) _q SiQSi(R ² ) _q (OH) _p (wherein R ² is substituted or unsubstituted monovalent hydrocarbon group, Q is an aromatic divalent hydrocarbon group, p
is 1 or 2, q is 1 or 2, but p+
q is 3) and (iii) the ratio ^{R 3 /} Si (where R ³ is a substituted or unsubstituted monovalent hydrocarbon group) is 1.05 to 1.6, and the ratio Ph/Si of the silicon atom (Si) to the phenyl group (Ph) directly bonded to it is 0.2 to 0.99, The content of hydroxyl groups directly bonded to silicon atoms is 8 to 10% by weight, and the softening temperature is 50 to 50%.
It consists of a phenyl group-containing organopolysiloxane resin at 120°C, and the mixing ratios of these are (i) 0 to 50% by weight, (ii) 50 to 95% by weight, and (iii) 0 to 50% by weight, and in this mixture. Organosilicon compounds with a silicon-bonded hydroxyl group content of 10% by weight or more
30 to 10 parts by weight, 100 parts by weight of a mixture, (b) 100 to 550 parts by weight of a filler, and (c) 0.05 to 5 parts by weight of a curing catalyst.