JP2716962B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an epoxy resin composition for encapsulating a semiconductor used for encapsulating a semiconductor device. The present invention relates to an epoxy resin composition for semiconductor encapsulation capable of producing a semiconductor device having excellent characteristics. 2. Description of the Related Art Semiconductor devices such as transistors, ICs and LSIs are usually sealed in ceramic packages or plastic packages to form semiconductor devices. Above all, the ceramic package itself has heat resistance as a constituent material, has low moisture permeability, and is a hollow package. Therefore, sealing with excellent heat resistance and moisture resistance is possible. However, there are disadvantages in that the constituent materials are relatively expensive and mass production is poor. Therefore, resin sealing using a plastic package has become mainstream from the viewpoint of cost and mass productivity. For this type of resin sealing,
Conventionally, epoxy resin compositions have been used and have achieved good results. Recently, an epoxy resin composition containing an epoxy resin, a phenol resin and spherical silica has been used in consideration of molding workability, particularly flowability. In addition, in consideration of low stress due to high integration of the element, a composition in which an organopolysiloxane is blended with an epoxy resin, a phenol resin, and a usual inorganic filler (non-spherical) has been developed. However, according to the former, the requirement for low stress property cannot be satisfied, and the latter has a drawback that the flowability is poor and the semiconductor element is stressed by the acute angle portion of the inorganic filler when flowing in the molding die. doing. [0003] As described above, the conventional 2
In fact, the type of epoxy resin composition does not sufficiently meet the requirements of moldability such as flowability and low stress, and a highly reliable semiconductor device has not been obtained. The present invention has been made in view of such circumstances, and uses a special component composition as an epoxy resin composition for resin encapsulation to provide flowability, low stress, heat resistance and moisture resistance. It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation capable of producing a highly reliable semiconductor device having excellent properties such as properties. In order to achieve the above object, the epoxy resin composition for semiconductor encapsulation of the present invention comprises the following (A), (B), (C), (D) and Component (E) is contained, and the above (D) / (E) weight ratio is 1
The configuration is set to 5/85 to 60/40. (A) Epoxy resin. (B) Novolak type phenol resin. (C) An organopolysiloxane having at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, a mercapto group and a carboxyl group. (D) A spherical amorphous silica powder having a Wardel sphericity of 0.5 to 1.0. (E) Non-spherical amorphous silica powder. That is, the inventors of the present invention have conducted a series of studies for obtaining a sealing resin having excellent reliability, and have found that the inorganic filler used as a filler has a sphericity of 0.5 to 1.0 with a Wardel sphericity of 0.5 to 1.0. When a special epoxy resin composition containing a spherical amorphous silica powder and a non-spherical amorphous silica powder having a specific ratio in a specific range, and further containing an organopolysiloxane having a functional group, is extremely excellent. The inventors have found that flowability, low stress, moisture resistance and molding workability can be obtained, and have reached the present invention. Next, an embodiment of the present invention will be described in detail. [0008] The present invention provides an epoxy resin (A component),
A novolak-type phenol resin (component B), an organopolysiloxane having at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, a mercapto group and a carboxyl group (component C); Which is obtained using a spherical amorphous silica powder (component (D)) having the following and a non-spherical amorphous silica powder (component (E)) and is usually in the form of a powder or a tablet obtained by compressing the powder. I have. Such an epoxy resin composition can be used as a highly reliable plastic package particularly by using the above-mentioned components C, D and E, and a highly reliable semiconductor device can be obtained by using the epoxy resin composition. It is something that can be done. The epoxy resin serving as the component A of the epoxy resin composition is not particularly limited as long as it is an epoxy compound having two or more epoxy groups in one molecule.
That is, the diglycidyl ether of bisphenol A and its multiplicity, such as epibis epoxy resin, bisphenol F epoxy resin, resorcin epoxy resin, alicyclic epoxy resin, and novolak epoxy resin, are appropriately selected and used. Of these, cresol novolak type epoxy resin is particularly preferable, and usually has an epoxy equivalent of 180 to 250 and a softening point of 50 to 130 ° C. The novolak type phenol resin of component B used together with the epoxy resin of component A has two or more hydroxyl groups in one molecule and functions as a curing agent for the epoxy resin. Novolak resin, cresol novolak resin and the like are appropriately selected and used. Among them, phenol novolak resins are preferred, and those having a hydroxyl equivalent of 100 to 130 and a softening point of 60 to 130 ° C are usually used. The C component organopolysiloxane used together with the A and B components includes an epoxy group, an amino group,
It has at least one functional group selected from the group consisting of a hydroxyl group, a mercapto group and a carboxyl group. That is, if a material having no functional group is used, the moldability and the sealability are deteriorated. The functional group may be bonded to the terminal of the organopolysiloxane molecule or may be bonded as a side chain. Preferably, the chemical structure of the organopolysiloxane other than the functional group portion is dimethylpolysiloxane. This may be partially substituted with a phenyl group instead of a methyl group. The organopolysiloxane having the functional group is preferably reacted in advance with at least one of the epoxy resin of the component A and the novolac phenol resin of the component B, whereby the epoxy resin composition contains It is preferable to form a state in which silicone rubber-like particles having a diameter of 5 μm or less are dispersed. In order to obtain such a particle dispersion system, the molecular weight of the organopolysiloxane having a functional group is preferably from 1,000 to 100,000. That is, if the molecular weight is less than 1,000, the organopolysiloxane dissolves into the resin skeleton and acts as a plasticizer without taking the shape of particles, causing a problem in the moisture resistance reliability of the semiconductor device to be obtained. This is because siloxane does not show affinity for the resin system, and it becomes difficult to react with the resin, and there is a tendency that the siloxane cannot be dispersed in the resin in a state of having a particle shape. The organopolysiloxane having the above functional group may be used alone or in combination. With respect to the organopolysiloxane having such a functional group, the equivalent weight per functional group is preferably from 1,000 to 100,000. This is for the same reason as the above molecular weight. The spherical amorphous silica powder of component D used together with the above components A, B and C has a sphericity of 0.5 to 1.0 in terms of Wardel's sphericity, and is a melt-solidified ingot. Mechanically crushed amorphous silica
From the obtained mechanically crushed material, a Wardel sphericity of 0.5 to
1.0, preferably those having a sphericity of 0.7 to 1.0, or ingot-shaped amorphous silica is mechanically pulverized and sprayed with high heat to obtain the same as above. One having sphericity is used. The Wardel sphericity is an index that measures the sphericity of a particle by (diameter of a circle equal to the projected area of the particle) / (diameter of the smallest circle circumscribing the projected image of the particle). The closer this index is to 1.0, the closer the particle is to a true sphere. When the Wardel's sphericity is less than 0.5, the amorphous silica powder becomes irregularly shaped (angular state) and obstructs the flow of the resin. Therefore, the spherical amorphous silica powder has a Wardel sphericity of 0.5 to 1.
It is necessary to have a sphericity of 0, preferably 0.7 to 1.0. Further, a non-spherical amorphous silica powder of component E is used together with the spherical amorphous silica powder of component D. This material has a worse sphericity than that of the spherical component D, and is sharp. Thus, the D component and E
Amorphous silica was selected as the filler component because of its small amount of impurities and small linear expansion coefficient, which can improve the heat resistance. The weight ratio of the spherical amorphous silica powder (component D) to the non-spherical amorphous silica powder (component E) must be set to D / E = 15 / 85-60 / 40. . That is, if the amount of the spherical amorphous silica powder is less than 15% by weight (hereinafter abbreviated as "%") in the total amount of the spherical and non-spherical particles, the flowability of the epoxy resin composition deteriorates, and the wires of the semiconductor element are cut during molding. The defective rate in the obtained semiconductor device is increased. On the other hand, if it exceeds 60%, the resin flows too much during transfer molding and voids are generated, which causes a problem in the moisture resistance of the obtained semiconductor device. is there. The content of the spherical amorphous silica powder (component D) and the non-spherical amorphous silica powder (component E) is preferably set to 50 to 85% of the entire epoxy resin composition. That is, if it is less than 50%, it is difficult to impart thixotropy to the epoxy resin composition, so that the molding workability is hindered, and at the same time, the thermal expansion coefficient does not decrease so much and the heat stress resistance becomes insufficient. This is because, if the ratio exceeds 3, a problem occurs during the molding operation as described above, and an unfilled portion of the epoxy resin composition occurs. The spherical amorphous silica powder (component D) and the non-spherical amorphous silica powder (component E) both preferably have a particle size of 149 μm or less, and more preferably have an average particle size of about 16 μm. Things. That is,
If the particle size exceeds 149 μm, the resulting semiconductor device
This is because an unfilled portion of the epoxy resin composition is caused to increase the rate of occurrence of defective products, and a problem tends to occur in molding workability. Further, according to the present invention, the above A, B, C,
In addition to the D and E components, if necessary, a curing accelerator,
Release agents, flame retardants, pigments and the like can be used. As the curing accelerator, any one that can be used as a catalyst for the curing reaction of the phenol-cured epoxy resin can be used, for example,
Tertiary amines such as triethylenediamine, 2,4,6-tri (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo [5.4.6] undecene, imidazoles such as 2-methylimidazole, and triphenyl And phosphorus-based compounds such as phosphine. The compounds exemplified as the above curing accelerators can be used alone or in combination. The epoxy resin composition used in the present invention comprises:
For example, it can be manufactured as follows. That is, the epoxy resin (A component) or the novolak-type phenol resin (B component) and the organopolysiloxane (C component) are stirred and mixed to perform a preliminary reaction. Next, this reaction product, a spherical silica powder having a specific sphericity (component D) and a non-spherical silica powder (component E), and if necessary, a curing accelerator, a release agent, a flame retardant, and a pigment, It can be produced by mixing and kneading by appropriately employing a dry blending method or a melt blending method according to a conventional method. Semiconductor encapsulation using such an epoxy resin composition is not particularly limited, and can be performed by a known molding method such as transfer molding. The semiconductor device thus obtained is extremely excellent in flowability, low stress, heat resistance and moisture resistance. As described above, the epoxy resin composition for semiconductor encapsulation of the present invention comprises a spherical amorphous silica powder (component D) having a specific sphericity and a non-spherical amorphous silica powder (E
Component) and a specific organopolysiloxane having a functional group (component C). Therefore, when a semiconductor element is sealed using this special epoxy resin composition, the sealing plastic package is different from the conventional one made of the epoxy resin composition, so that it has excellent flowability and low stress, and Humidity reliability,
A semiconductor device having high reliability such as heat resistance can be obtained. Next, examples will be described together with comparative examples. Examples 1, 2, 4, 5 and Comparative Examples 2 and 3 In accordance with the following Tables 1 and 2, the epoxy resin was heated in a separable flask equipped with a stirrer, and the organopolysiloxane was added thereto. It was added and stirred and mixed at 170 ° C. for 4 hours. Then, the remaining raw materials are blended with the obtained reaction product, melt-kneaded in a mixing roll machine (roll temperature: 80 to 100 ° C.) for 3 minutes, cooled, solidified, and then pulverized to obtain the desired fine powder epoxy. A resin composition was obtained. Examples 3 and 6, Comparative Example 1 Instead of the epoxy resin, phenol resins shown in Tables 1 and 2 below were used. Otherwise, in the same manner as in Example 1, the desired fine powder epoxy resin composition was obtained. The above Examples 1 to 6 and Comparative Examples 1 to
The structure, equivalent weight, average molecular weight of the organopolysiloxane used in Example 3, and the sphericity and average particle size of the spherical amorphous silica powder are as shown in Table 3 below. [Table 1] [Table 2] [Table 3] Comparative Example 4 In Example 1, the spherical amorphous silica powder having a Wardel sphericity of 0.4 was replaced by a spherical amorphous silica powder having a Wardel sphericity of 0.7. A fixed silica powder was used. Otherwise, in the same manner as in Example 1, the desired fine powder epoxy resin composition was obtained. Comparative Example 5 In Example 1, non-spherical amorphous silica powder was not used as silica powder, but spherical amorphous silica powder was used. The amount of the spherical amorphous silica powder in the epoxy resin composition was 300 parts by weight (hereinafter abbreviated as "part"). Otherwise, in the same manner as in Example 1, the desired fine powder epoxy resin composition was obtained. Comparative Example 6 In Example 1, a non-spherical amorphous silica powder was used instead of a spherical amorphous silica powder as the silica powder. And the compounding quantity of the non-spherical amorphous silica powder in the said epoxy resin composition was 300 parts. Otherwise, in the same manner as in Example 1, the desired fine powder epoxy resin composition was obtained. Comparative Example 7 In Example 1, the blending amount of the spherical amorphous silica powder was changed to 30 parts, and the blending amount of the non-spherical amorphous silica powder was changed to 270 parts. Otherwise, in the same manner as in Example 1, the desired fine powder epoxy resin composition was obtained. Comparative Example 8 In Example 1, the blending amount of the spherical amorphous silica powder was changed to 195 parts, and the blending amount of the non-spherical amorphous silica powder was changed to 105 parts. Otherwise, in the same manner as in Example 1, the desired fine powder epoxy resin composition was obtained. Using the fine-powder epoxy resin compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 8, a semiconductor element was transfer-molded (180 ° C. × 2 minutes).
As a result, a 42-pin DIP semiconductor device was obtained. The semiconductor device thus obtained was post-cured at 175 ° C. for 5 hours. After using each of the 50 semiconductor devices as a sample and performing a temperature cycle test (immersion in silicone oil) 500 times at −80 ° C./5 minutes to 150 ° C./5 minutes, the sealing resin is removed and the surface of the semiconductor element surface is removed. The number of occurrences of passivation cracks was examined. The results are shown in Table 4 below together with the filling properties of the sealing resin during molding. [Table 4] From the results in Table 4, it was found that spherical amorphous silica powder having a sphericity out of the specified range was used, and the mixing ratio of the spherical amorphous silica powder and the non-spherical amorphous silica powder was out of the specified range. Comparative Example 1 used, Comparative Example 2 not using organopolysiloxane, spherical amorphous silica powder having a sphericity out of a specified range, and spherical amorphous silica powder and non-spherical amorphous silica powder. Comparative Example 3 using a compounding ratio out of the specified range and using no organopolysiloxane, Comparative Example 4 using spherical amorphous silica powder having a sphericity out of the specific range
The products and Comparative Examples 5 to 8 in which the mixing ratio of the spherical amorphous silica powder and the non-spherical amorphous silica powder was out of the specific range were inferior in either the filling property or the thermal shock resistance. On the other hand, it can be seen that the products of the examples are both excellent and have improved reliability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 83/08 C08L 83/08 // H01L 23/29 H01L 23/30 R 23/31 (56) References JP-A-64-40518 (JP, A) JP-A-63-202622 (JP, A) JP-A-62-151447 (JP, A) JP-A-61-268750 (JP, A) JP-A 61-268750 JP-254619 (JP, A) JP-A-62-63453 (JP, A) JP-A-62-50325 (JP, A) JP-A-62-63450 (JP, A) JP-A-60-55025 (JP, A) ) JP-A-62-7723 (JP, A)

Claims (1)

(57) [Claims] The following (A), (B), (C), (D) and (E)
JP that containing components, and the weight ratio of the component (D) / (E component) is set to 15/85 to 60/40
Epoxy resin composition for semiconductor encapsulation according to symptoms. (A) Epoxy resin. (B) Novolak type phenol resin. (C) An organopolysiloxane having at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, a mercapto group and a carboxyl group. (D) A spherical amorphous silica powder having a Wardel sphericity of 0.5 to 1.0. (E) Non-spherical amorphous silica powder. 2. 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the spherical amorphous silica powder as the component (D) has a sphericity of 0.7 to 1.0 in Wardell's sphericity. 3.
Thing . 3. The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, wherein the molecular weight of the organopolysiloxane as the component (C) is 1,000 to 100,000. 4. 4. The semiconductor according to claim 1, wherein the spherical amorphous silica powder as the component (D) and the non-spherical amorphous silica powder as the component (E) each have a particle size of 149 μm or less. 5. Epoxy resin composition for sealing .