JPS5895846A - Resin seal type semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the resin seal type semiconductor device having excellent reliability regarding dampproof property, high-temperature electric characteristics, etc. by using a hargener manufactured by combining polyoxystyrene and novolac type phenol resin and an epoxy resin composition employing an organic phosphine hardening accelerating agent as sealing resin. CONSTITUTION:The composition consisting of the novolac type epoxy resin of 170-300 epoxy equivalent, polyoxystyrene, novolac type phenol resin and an organic phosphine compound is used as the composition for sealing. Molecular weight extending over a wide range can be employed as the molecular weight of polyoxystyrene, but approximately 300-30,000 is preferable from the viewpoint of practicality. It is preferable that the compounding ratio of novolac type phenol resin is within the range of 0.01-100wt.pt. novolac type phenol resin to 1wt. polyoxystyrene. The quantity of the organic phosphine compound compounded may generally be within the range of 0.001-20wt% of resin components (the total amount of epoxy resin and the hardener), but the epoxy resin composition having excellent dampproof property and superior curing characteristics can be obtained especially when the quantity is brought within the range of 0.01- 5wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical field to which the invention pertains The present invention relates to a highly reliable resin-sealed semiconductor device encapsulated with a cured product C2 of a resin composition manufactured by the present invention.

(2)) Technical background of the invention and its problems Epoxy resin has excellent electrical properties, mechanical properties, and chemical resistance, so it is widely used as a highly reliable electrical insulating material for encapsulating semiconductor devices. .

In its place, conventional semiconductors are used for fcI\-metic sealing; instead, most semiconductors are manufactured using low-pressure molding for integrated circuits, large-scale inspection integration, transistors, diodes, etc. The stings are made using an epoxy resin composition.

As epoxy resin compositions for semiconductor encapsulation, epoxy resin compositions consisting of epoxy resin, Novolak phenol street resin curing agent, indazole hardening accelerator, etc. are widely used in order of reliability, moldability, etc. It is used.

However, the paulownia resin-sealed p-conductor device obtained by molding the conventional epoxy sealing resin into a sphere has the following drawbacks. (1) Requirements for resin-sealed semiconductor H Moisture resistance is inferior compared to the high level of axial properties <z) m Grease-sealed semiconductor devices; high level of reliability claimed l2 Inferior electrical properties at high temperatures Regarding the above-mentioned moisture resistance, resin-sealed semiconductor devices are sometimes used or stored in high-temperature, high-humidity environments, so reliability must be maintained even under such conditions. As an evaluation test to maintain the quality of moisture resistance, an accelerated evaluation method has been used in which exposure is performed in saturated water vapor at 120°C before 85°C, and recently, a voltage is applied to evaluate the acceleration Evaluation tests with increased bias application have also been conducted.

However, since the cured material of the sealed epoxy resin composition has moisture permeability, under such high temperature and humid conditions, moisture from the outside passes through the cured material layer of the sealed resin and permeates into the interior. Then, 9 enters the interior through the interface between the sealing resin and the lead frame, and enters the t! of the semiconductor element. I & Kaya I: Reach in the trench.

As a result of the action of this moisture and impurity ions present in the sealing resin, the insulation properties of the semiconductor device deteriorate, leakage current increases, and corrosion of aluminum electrodes, wiring, etc. Defects mainly occur. Furthermore, when a bias voltage is applied, defects due to electrochemical action (=corrosion of the naltanium electrode and wiring) occur extremely frequently.

Conventional IIN encapsulated semiconductor devices are not fully satisfied with the moisture resistance mentioned above, and improvements in moisture resistance have been required. Since Iic is sometimes used under high temperature conditions, even under such conditions I! The quality of the mackerel must be guaranteed. For this purpose, the evaluation test is from 80℃ to 1
An accelerated test in which reliability is evaluated by applying a bias voltage at 50° C. is common.

In such tests 62, devices with a MOB structure with a sensitive surface or devices with a PN junction to which a reverse bias was applied
'-It is well known that one of the most frequently occurring defects is the phenomenon of increased leakage current due to channeling. This phenomenon is thought to occur because an electric field acts on the resin layer 1 in contact with the surface of the element to which a voltage is applied. In terms of characteristics, sufficient C; unsatisfactory and improvement was required.

(3) Purpose of the Invention The purpose of the present invention is to improve the drawbacks of such conventional resin-sealed semiconductor devices.
2. To provide a highly reliable resin-sealed semiconductor device having excellent moisture resistance and high IIL electrical characteristics.

(4) Summary of the Invention In order to achieve the above object, the inventors of the present invention have conducted extensive research and have discovered that curing accelerators are the cause of the above defects. Oxystyrene and, if necessary, a combination of novolac type phenolic resin as a curing agent, and organic phosphine as a curing accelerator.
It was discovered that the tatami epoxy resin composition has superior properties as a semiconductor encapsulating resin compared to the conventional epoxy resin compositions using phenolic resin, imidazole, and tertiary amine, and the use of this composition (2) It has been found that a resin-sealed semiconductor device with excellent reliability in terms of performance and high-temperature electrical properties can be obtained.

That is, the present invention provides a cured product of an epoxy resin composition in which (a) epoxy resin < 1y) polyoxystyrene and (0) an organic phosphine compound is essential.
2. This is a resin-sealed semiconductor device characterized in that the semiconductor device is sealed. In the present invention, the above composition I can also be used in combination with the addition of novolak and sphenol resin. Further, as the epoxy resin, a novolac type epoxy resin having an epoxy equivalent of 170 to 300 can also be used. In the present invention, a composition comprising (S) a novolac type epoxy resin having an epoxy equivalent of 170 to 300, (b) polyoxystyrene, (C) a novolac type phenol resin, and an organic phosphine compound is preferred in the present invention.

The epoxy resin #'i used in the present invention is a commonly known resin and is not particularly specified. For example, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl ester type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, etc. porcelain resin, complex mm
Examples include epoxy resins having two or more epoxy groups in one molecule, such as epoxy resins and halogenated epoxy resins. However, these epoxy resins may be used alone or in a mixed system of two or more.

Preferable epoxy resins used in the present invention I: are novolac epoxy resins having an epoxy equivalent of 170 to 3000, such as phenol novolak cap epoxy resin, cresol novolak epoxy resin, halogenated phenol novolac Nada epoxy resin, etc. These epoxy resins may be used alone or in combination of two or more. Epoxy resins other than the above, such as bisphenol epoxy resins, general glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, glycidyl ether type epoxy resins, linear aliphatic epoxy resins, alicyclic epoxy resins, and complex epoxy resins. The resin and halogenated epoxy resin can be used in combination with the novolac type epoxy resin 1 having an epoxy equivalent of 170 to 300. The blending amount is preferably 50% by weight or less based on Novo2Tsuku Epoxy Paulownia C2. In addition, these epoxy resins have a chlorine ion content of 10pp.
It is desirable that the content of hydrolyzable chlorine is 0.1 weight or less. The reason for this is that if chlorine ions in excess of FilOppm or hydrolyzable chlorine in excess of 0.1 weight are contained, the aluminum electrode of the sealed semiconductor element is likely to be corroded.

The polyoxystyrene used in the present invention is 0-
C- can be easily obtained by carrying out ionic or radical polymerization of one or more of oxystyrene, m-oxystyrene, p-oxystyrene, and halogenated oxystyrene or a combination of 2s or more. It can also be obtained by hydrolyzing a polymer of alkoxystyrene or acyloxystyrene. The molecular weight of polyoxystyrene can be used in a wide range, but from the viewpoint of practicality, it is preferably about 300 to about 300 to about 300,000,000.

In the present invention, the novolac phenolic resin used according to Desired 1: phenol novolac resin,
Cresol novolak resin, -1butylphenol novolak resin, nonylphenol novolak resin, etc. are mentioned.

Regarding the blending ratio of epoxy@M'rl and polyoxystyrene, the ratio of the number of 7-enol hydroxyl groups in polyoxystyrene to the number of epoxy groups in the epoxy resin is 0.5 to 1.
It is preferable to mix 6 to within the range of 5 to 6. When a novolac type phenolic resin is used in combination, the ratio of the sum of the numbers of 7-enolic hydroxyl groups in polyoxystyrene and novolak 11 phenolic resin to the number of epoxy groups in the epoxy resin (total number of hydroxyl groups/number of epoxy groups) is 0.5~
Preferably, it is within the range of 1.5. The reason for this is that when tj is less than 0.5 or exceeds 1.5, the reaction becomes difficult to occur sufficiently, and the properties of the cured product tend to deteriorate. The blending ratio of polyoxystyrene and Novolak phenolic resin is 1 to 2 parts by weight of polyoxystyrene to 0.01 to 10.01 parts by weight of Novo 2 Ivy phenolic resin. This is preferable because if the amount is less than 0.01 parts by weight or more than 100 parts by weight, the effects of novolac 11 phenol resin and polyoxystyrene resin will not be sufficiently recognized, respectively.

When mixing the composition of the present invention, each component may be blended individually in powder form, but in advance, epoxy resin, polyoxystyrene, polyoxystyrene, and Norac Star phenolic resin may be mixed. The advantage of using a melt mixture is that the compatibility between the epoxy resin and the curing agent is improved, and therefore the final epoxy resin composition The properties of the cured product are made more uniform.

゛In the present invention, as the organic phosphine compound used as a curing accelerator, Fi1 formula: 4 = R1
- Tertiary phosphine compound s in which all R@s are organic groups
Second phosphine compound b where only R1 is hydrogen R1,R
There is a primary phosphine compound in which both 11 are hydrogen.

Specific examples thereof include triphenylphosphine, tributylphosphine, trisicμhexylphosphine, methyldiphenylphosphine, butylphenylphosphine, diphenylphosphine, phenylphosphine, octylphosphine, and the like. Further, R1 may be an organic group containing an organic phosphine. For example, 1,2-bis(diphenipy
*Syi/) ethane, bis(diphenylphosphino)methane, etc.

Among these, arylphosphines are preferred, and triarylphosphines such as %-12-diphenylphosphine are preferred. Moreover, these organic phosphine compounds are III
Alternatively, a mixture of two or more types may be used. However, the blending amount of this organic phosphine compound may be within the range of 0.00 to 20% by weight of the resin component (total amount of epoxy resin and curing agent), but particularly preferred properties are 0.01 to 5% by weight. By setting the blending amount of the organic phosphine compound within the range of 0% to within this range, it is possible to obtain an epoxy resin composition with excellent moisture resistance and excellent curing properties. The amount added is 0.0
If the weight is less than 0.01, the effect of addition will be poor, and the curing of the epoxy resin composition will take a long time.
If it exceeds 0 weight, it is moisture resistant; no adverse effects occur.

Epoxy resin composition I of the present invention: An inorganic filler can be blended depending on public welfare requirements, but especially in the case of transfer molding of semiconductor water molecules such as integrated circuits and transistors, an inorganic filler is blended. It is preferable to do so. One reason for this is to improve moldability, and another reason is to reduce the difference in thermal expansion coefficient between the parts to be pierced, such as elements, bonding wires, and lead frames, and the sealing etNI. This is to reduce defects that occur due to a large difference in thermal expansion coefficients, such as bonding wire breakage.

Inorganic fillers used in the present invention include quartz glass powder, crystalline silica powder, glass fiber, talc, Al-Z powder, calcium silicate powder, calcium sulfate powder, barium sulfate powder, and more! Among them, quartz glass powder and crystalline silica powder are most preferred in terms of high purity and low coefficient of thermal expansion. However, the blending amount of these inorganic fillers varies depending on the type of epoxy resin, phenolic resin curing agent, and inorganic filler, but for example, when used for transfer molding, the total amount of epoxy resin and phenolic resin curing agent is 1; However, the weight ratio may be about 1.6 to 4 times.

Regarding the particle size distribution of the inorganic filler, moldability can be improved by making the distribution uniform by combining coarse particles and fine particles.

Invention 1: The epoxy resin composition may be prepared using a mold release agent such as natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters or paraffins, and chlorinated Flame retardants such as paraffin, boomtoluene, hexabromobenzene, antimony trioxide,
Coloring agents such as carbon black, silane coupling agents, etc. may be added and blended as appropriate.

A general method for preparing the epoxy resin composition according to the present invention as a molding material is to thoroughly mix the raw material components selected in a predetermined composition ratio, for example, with a mixer, and then further process C: melt-mixing with a hot roll. , 1: Epoxy resin molding material can be easily obtained by adding a mixing treatment using C2 such as ti=-der.

The resin-sealed semiconductor device of the present invention can be easily manufactured by encapsulating the semiconductor device using the above-mentioned epoxy resin composition or molding material.

The most common method for sealing is low-pressure transfer molding, but sealing by injection molding, compression molding, casting, etc. is also possible. Special sealing methods include sealing the semiconductor surface using a solvent-based or non-solvent-based composition, and can also be used for localized sealing as a so-called solar coating. .

The epoxy resin composition or molding material is heated and cured at the time of sealing, and the final g; can. During curing, it is desirable to heat to 150° C. or higher.

The semiconductor device referred to in the present invention includes an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, etc., and is not limited to %I.

(Effects of the Invention) As is clear from the above object of the present invention, the description of the outline, and the following examples, the epoxy resin composition of the present invention is used as a semiconductor encapsulation resin. As shown in 62, corrosion breakage of aluminum wiring due to moisture 1 is significantly reduced, moisture resistance is improved, and leakage current due to MO8B test is significantly reduced. : Electrical properties at high temperatures are improved.

(6) Examples of the invention Next I: Examples of the present invention will be explained.

Reference example 1~! S Epoxy Mushikei 220 cresol novolak epoxy resin (epoxy resin), polybala oxystyrene with a weight average molecular weight of 8000 (hydroxyl equivalent: 12oL, phenol novolac resin with a weight average molecular weight of 800), curing agent (hydroxyl equivalent: 104)% :yelphosphine, -
2-Methylated 1! The composition ratio (parts by weight) i shown in -1 was selected, and each composition was ground and mixed in a mortar to prepare a powdery mixture.

In order to evaluate the curing speed of each composition obtained in this manner, the gelation time was determined on a hot plate at 160°C. The results are shown in Table 21.

1! -1 Table-2 Example 1-4 Cresol novolac type epoxy resin (contains epoxy resin) with epoxy weight 220, brominated epoxy resin (epoxy resin B) with epoxy weight 290, weight average molecular weight s,
o o o polyparaoxystyrene (hydroxyl equivalent: 1
20), P-hatched polyparaoxystyrene with a weight average molecular weight of 10.000 (hydroxyl equivalent: 240), phenol novolak resin with a weight average molecular weight of 800 (hydroxyl equivalent: 10)
4), triphenylphosphine, 2-ethyl-4-If
Composition ratios of limidazole, penzyldimethylamine, quartz glass powder, antimony trioxide, carnauba wax, carbon black, and silicon coupling agent (r-glycidoxyprobyltrimethoxysilane) shown in Table 3+=
Part by weight) C: Select and mix each composition by mixing,
Heating roll I: 10 types of transfer molding materials including comparative examples were prepared by cross-circulating the wires according to 0 Transfer molding using the molding materials obtained by CI: Second, the UOSW integrated circuit side The abdomen was sealed. For sealing, the molding material was heated to 90°C with a high-frequency preheater and heated to 175°C.
It was molded at ℃ for 2 minutes, but it could not be molded. The following test was conducted on 100 of the above resin-sealed semiconductor devices.

(1) A moisture resistance test (bias POT) was conducted in which 1Ov was applied in water vapor at 120° C. and 2 atm to check for disconnection defects due to corrosion of the aluminum wiring, and the results are shown in Table 4C.

(2) Offset gate M in a 100℃ oven
Drain voltage 57.0811 to the circuit. A test (MOS-BT test) is performed to check for leakage current defects due to deterioration of electrical characteristics by applying an offset gate voltage of 5V, and if the leakage current increases to more than 100 times the initial value, it is determined to be a defect. is shown in Table 5C.

Below, margin Table 3 - 5 Table 6 - Composition 62 According to the compositions shown in Table 6, the transfer forming materials in 111, including the comparative example, were adjusted, and a resin-sealed semiconductor device was prepared in the same manner as in Examples 1 to 4. Manufacture bias PC
? Test, MOEI-BT test was conducted. The results are shown in Table-7 and Table-86, respectively.

Claims (1)

[Claims] 1) A cured product C of an epoxy resin containing (g) an epoxy resin (1,) polyoxystyrene and (0) an organic phosphine compound as essential components; thus, the intermediate body device is sealed. A resin-sealed semiconductor device 2 characterized in that the ratio of the number of 7-enolic hydroxyl groups of polyoxystyrene to the number of epoxy groups of the epoxy resin is 0.5 to 1. 3) Resin-sealed semiconductor device within the range of 0.5 to 0.001 to 0.5 to the total weight of the epoxy resin and polyoxystyrene. (a) Epoxy resin (→polyoxystyrene (C) novolac type phenol resin and (cured product C of an epoxy resin composition containing an essential organic phosphine compound) 2) A resin-sealed semiconductor device characterized in that the semiconductor device is sealed. 6) In the statement of claim 4, the ratio of polyoxystyrene and novolac type phenol resin is 1 to 1.
Weight part I: Novolac phenol resin is 0.01
Resin-sealed semiconductor device in the range of ~100 parts by weight 7) Statement I in claim 4: The total number of phenolic hydroxyl groups in polyoxystyrene and novolak-type phenolic resin and novolak-type epoxy resin. 8) A resin-encapsulated semiconductor device in which the ratio of the number of epoxy groups is within the range of 0.5 to 1.5. For each grain amount C of styrene and novolac phenol resin, 0.
Within the range of 001 to Chiang Chung 1* 1: A certain resin-sealed semiconductor device 9) Description 1 of claim 1 or 4; in which the epoxy resin composition contains an inorganic filler. Sealed semiconductor device 10) 41 A resin-sealed lid semiconductor device according to claim 4, which is a molten mixture of polyoxystyrene, which is an essential component of an epoxy resin composition, and a novolak phenol resin.