JPS62210653A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a device, which can cope with the implementation of a large configuration, by using an epoxy resin composition including specified components, thereby implementing low stress in a sealing resin. CONSTITUTION:For an epoxy resin composition used for sealing, an epoxy resin and a phenol resin are used. The composition is obtained by using at least one of the following material: polypropylene glycol oligomer, which has epoxy groups at both ends of molecule chain; polypropylene glycol oligomer, which has amino groups at both ends of a molecule chain; and polyalkylene glycol oligomer expressed by the formula. In the formula; R is an alkylene group, in which the number of carbon is 4 or less; (n) is an integer of 10-200; and R1 and R2 are alkyl groups, in which the number of hydrogen or carbon is 3 or less. Since the sealing resin has very low stress, high reliability is obtained in a large semiconductor device, whose long side of the chip is 4mm or more while the number of pins is 8 is more, especially 16 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device with degraded reliability.

[Conventional technology]

Semiconductor elements such as transistors, ICs, and LSIs are usually sealed with ceramic packages, plastic packages, or the like to form semiconductor devices. The above-mentioned ceramic package has heat resistance in the constituent material itself,
It also has excellent moisture permeability, so it is resistant to temperature and humidity, and because it is a hollow package, it has high mechanical strength and can be sealed with high reliability. However, since the constituent materials are relatively expensive and the mass productivity is poor, resin sealing using the above-mentioned plastic package has become mainstream in recent years.

In particular, recent technological innovations in the semiconductor field have led to improvements in the degree of integration, larger element sizes, and finer interconnections.
Along with this, there is a demand for improved reliability (internal stress reliability, moisture resistance reliability, shock resistance reliability, heat resistance reliability, etc. of the resulting semiconductor device) of encapsulation materials, and in particular, semiconductor encapsulation There is a strong demand for resins for semiconductor devices to have the property that the stress exerted on semiconductor devices is small even when directly molded.

As a resin for semiconductor encapsulation, an epoxy resin composition containing an epoxy resin, a novolac type phenol resin, and an amorphous filler as main components, and further containing a curing accelerator, a coloring agent, and a mold release agent is widely used.

However, when semiconductor devices are molded with this type of sealing resin, the stress of the resin can cause cracks in the passivation film or the device itself, or misalignment of aluminum wiring, etc., due to the stress of the resin, which has rarely been a problem in the past. I've come to understand. This is clearly noticeable due to the large dimensions of the element itself.

Therefore, as a countermeasure to this problem, the development of a resin that applies less stress to the element (low-stress resin) has become a major issue today. Possible methods for achieving this objective include making the phenolic resin itself flexible or adding a plasticizer. However, in the case of an epoxy resin composition using a phenol resin as a curing agent, the glass transition point of the cured resin is lowered and the high-temperature electrical properties are lowered, so there is a problem in terms of reliability. It is also possible to reduce the stress applied to the element by adding synthetic rubber, etc., but adding synthetic rubber reduces the adhesion of the resin composition to the semiconductor element and lead frame. However, moisture resistance deteriorates and reliability decreases.

[Problem that the invention seeks to solve]

As mentioned above, conventional encapsulating resins have not been satisfactory in terms of stress on semiconductor elements, but have been developed to meet the needs of larger element sizes due to the technological innovations mentioned above. There is a strong desire for improved characteristics.

This invention was made in view of the above circumstances, and its purpose is to reduce the stress of a sealing resin without impairing its reliability, thereby making it possible to cope with the increase in the size of semiconductor devices. It is something.

[Means for solving problems]

In order to achieve the above object, the semiconductor device of the present invention contains the following components (A) and (B), and furthermore, (
The semiconductor device is encapsulated using an epoxy resin composition containing at least one component selected from the group consisting of components C), (D), and (E).

(A) Epoxy resin (B) Phenol resin (C) Polypropylene glycol oligomer having epoxy groups at both ends of the molecular chain.

(D) A polypropylene glycol oligomer having amino groups at both ends of the molecular chain.

(E) A polyalkylene glycol oligomer represented by the following general formula (1).

R1-0±RO-+TRz... (1) That is, this invention relates to a polyalkylene glycol oligomer having an epoxy group at both ends of the molecular chain, a polyalkylene glycol oligomer having an amino group at both ends of the molecular chain, and the above general formula Since semiconductor devices are encapsulated using a special epoxy resin composition containing at least one of the polyalkylene glycol oligomers represented by (1), there is no problem with conventional encapsulation resins due to the addition of plasticizers, etc. It is possible to reduce the stress of the encapsulating resin without causing a decrease in high-temperature electrical properties or a decrease in the adhesion of the encapsulating resin to the semiconductor element due to the addition of synthetic rubber, thereby increasing the size of the element, etc. Be able to respond to

The epoxy resin composition used in this invention uses an epoxy resin (component A) and a phenol resin (component B), and further contains two polypropylene glycol oligomers (component C) having epoxy groups at both ends of the molecular chain. Polypropylene glycol oligomer (D
component) and a polyalkylene glycol oligomer represented by the above general formula (1) (component E), and is usually in the form of a powder or a tablet formed by compressing it. There is.

In addition, the above-mentioned "oligomer" is used to include dimers.

The epoxy resin serving as the above A component is not particularly limited, and various epoxy resins conventionally used as encapsulating resins for semiconductor devices can be mentioned, such as Talesol novolac type, phenol novolac type, and bisphenol A type. . Among these resins, it is preferable to use one that has a melting point above room temperature and is in the form of a solid or highly viscous solution at room temperature. Novolac type epoxy resin usually has an epoxy equivalent of 160 to 25.
0. Those with a softening point of 50 to 130°C are used, and cresol novolak type epoxy resins have an epoxy equivalent of 1
Those having a softening point of 80 to 21°C and a softening point of 60 to 110'C are generally used. Moreover, as a phenol novolac type epoxy resin, the epoxy equivalent is 160 to 250. Softening point 5
0 to 130''C is generally used.

The phenol resin of component B used together with the epoxy resin acts as a curing agent for the epoxy resin, and includes phenol novolak, 0-cresol novolak, m-cresol novolak, p-cresol novolak, and 0-ethylphenol novolak. , m-ethylphenol novolak, p-ethylphenol novolak, etc. are preferably used. These novolak resins are
It is preferable to use one having a softening point of 50 to 110°C and a hydroxyl equivalent of 70 to 150.

The polypropylene glycol oligomer having epoxy groups at both ends of the molecular chain, which is the component C, has the following general formula (2
).

In particular, when the repeating number n of the polypropylene glycol oligomer represented by the above formula (2) is less than 10, the heat resistance of the semiconductor device obtained using it decreases, and conversely, when n exceeds 200, the heat resistance of the semiconductor device obtained using it decreases. In this case, a decrease in the reliability of semiconductor devices is observed. Therefore, it is preferable to use one in which the number of repetitions n is set within the range of 10 to 200. As such a polypropylene glycol oligomer (component C), a commercially available product can be used as is.

In addition, component D, a polypropylene glycol oligomer having amino groups at both ends of the molecular chain, has the following general formula (3
).

11□N-R+C3H60-h-R-NHz ・・
- (3) In this D component, the repeating number n and R can be set in the same manner as in the C component represented by the general formula (2), a polypropylene glycol oligomer having epoxy groups at both ends of the molecular chain. Brings good results. As such a polypropylene glycol oligomer (component D), for example, a commercially available product shown below can be used as is.

Furthermore, a commercially available product can also be used for the polyalkylene glycol oligomer R70tROS;-R,.(1) represented by the general formula (1), which is component E. Among the above polyalkylene glycol oligomers, polypropylene glycol oligomers in which R is a propylene group are preferably used. In the above general formula (1), when the number of repetitions n is less than 10, the heat resistance of the semiconductor device obtained by using it decreases, and conversely, when it exceeds 200, the reliability of the semiconductor device decreases. can be seen. Therefore, also in the above formula (1), it is preferable to use one in which the number of repetitions n is within the range of 10 to 200.

Each of the above components C, D, and E is used together with the above components A and B, and at that time, they may be used alone or in appropriate combinations. Also, C, D,
There is no problem in using the three components of E at the same time. When these C, D, and E components are used, whether they are used alone or in combination, they are not included in the epoxy resin (
Component A) 2 to 100 parts by weight (hereinafter abbreviated as "parts")
It is preferable to set the amount to 50 parts, preferably 5 to 30 parts. If the above-mentioned components are less than 2 parts, the stress reduction effect will be reduced, resulting in poor reliability of the resulting semiconductor device, and conversely, if it is more than 50 parts, the heat resistance of the semiconductor device will be reduced. It is from.

In addition to the above-mentioned raw materials, a curing accelerator may be used if necessary. Suitable examples of the curing accelerator include the following tertiary amines, quaternary ammonium salts, imidazoles, and boron compounds, which may be used alone or in combination.

Tertiary amines triethanolamine, tetramethylhexanediamine, triethylenediamine, dimethylaniline, dimethylaminoethanol quaternary ammonium salts dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride imidazoles 2-methylimidazole, 2-undecyl Imidazole, 2-ethylimidazole, 1-benzyl-2-methylimidazole boron compound triethyleneamine tetraphenylborate, N-methylmorpholine tetraphenylborate, tetraphosphonium tetraphenylborate and, if necessary, an inorganic filler.

Flame retardants such as antimony trioxide and phosphorus compounds, pigments, coupling agents such as silane coupling agents, and mold release agents such as stearic acid, metal salts thereof, and wax can be used. The inorganic filler is not particularly limited, and may include commonly used quartz glass powder, talc, and silica powder.

Alumina powder, clay, calcium carbonate, zirconium oxide, zirconium silicate, helium oxide, etc. are used as appropriate.

The epoxy resin composition used in this invention can be produced, for example, as follows. That is, the above A~
Ingredient E and other additives such as inorganic fillers, pigments, coupling agents, etc. are appropriately blended, and this mixture is kneaded in a heated state using a kneading machine such as a mixing roll machine to melt and mix. It can be produced by a series of steps of cooling the powder to a temperature of 100%, pulverizing it by known means, and, if necessary, compressing it into tablets.

In addition, regarding the above C-E component, as mentioned earlier,
It is not necessary to mix all of these into the epoxy resin composition, and any one of the C component, D component, and E component, or the combination of C+D component, C+E component, D+E component, or the combination of C+D+E component, etc. It can be blended with

Sealing of a semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by a conventional method, for example, a known molding method such as transfer molding.

The semiconductor device obtained in this way has extremely excellent electrical properties and low stress properties, because the internal stress of the cured epoxy resin composition is set to be low without adding plasticizers, synthetic rubber, etc. Become something. Further, the C component to the E component can be obtained at relatively low cost, so that the semiconductor device can have the low stress property at low cost.

[Effects of the Invention] The semiconductor device of the present invention uses a polypropylene glycol oligomer (component C) having epoxy groups at both ends of the molecular chain.
Polypropylene glycol oligomer having amine groups at both ends of one molecular chain (component D) and the above general formula (1)
It is sealed with a special epoxy resin composition containing at least one of the polyalkylene glycol oligomers (component E) represented by, and the sealing resin has extremely low stress. Alternatively, high reliability as described above can be obtained in large semiconductor devices where the long side of the chip is four or more squares, and this is a major feature. Furthermore, it does not increase costs and is extremely practical.

Next, examples will be described.

[Examples 1 to 19. Comparative example, conventional example] First, as a C component, the following first polypropylene glycol oligomer having epoxy groups at both ends of the molecular chain was used.
Six types of oligomers C-1 to C-6 shown in the table were prepared, and D-1 shown in the table was also prepared as a polypropylene glycol oligomer having amine groups at both ends of the molecule.

In addition, as the E component, E-1 to E- shown in Table 1 below
4 types were prepared.

(The following is a blank space) Next, the raw materials shown in Table 2 are blended with the above C to E components in the proportions shown in the same table, and this is kneaded for 10 minutes at 100'C using a mixing roll machine to form a sheet-like composition. I got it. Then, the obtained sheet-like composition was pulverized to obtain a powdered epoxy resin composition.

(The following is a blank space) A semiconductor device was obtained by molding a semiconductor element by transfer molding using the powdered epoxy resin composition obtained in the above Examples, Comparative Examples, and Conventional Examples. For the semiconductor device obtained in this way, the bending elastic modulus, internal stress due to piezoresistance, -50°C
Measurements were conducted including a 2000-times temperature cycle test (hereinafter referred to as "rTCT test") of 15 minutes to 150° C. for 15 minutes, and a 1000-hour reliability test using a pressure cooker under voltage application (hereinafter referred to as "rPCBT test"). The results are shown in Table 3 below.

Note that the glass transition temperature (Tg) is the viscoelastic property Tanδ
The temperature at which the peak occurs is shown.

(Left below) From the results in Table 3, it can be seen that the actual height measurement was higher than that of the conventional product.
The defective rate of the test and the crack occurrence rate of the TCT test are low (
It can be seen that it has excellent heat resistance and thermal shock resistance, and has high reliability. In addition, in the comparative height measurement, the E component whose repetition number n exceeds 200 in the above formula (1) is used as the E component.
-4 components are used, so the results are slightly worse than the actual height measurements.

The presence of the C component to E component in the epoxy resin composition measured can be confirmed by analysis using infrared absorption spectroscopy (IR).

Claims (1)

[Claims] (1) An epoxy resin composition containing the following components (A) and (B), and further containing at least one component selected from the group consisting of components (C), (D), and (E). A semiconductor device that uses a material to seal a semiconductor element. (A) Epoxy resin (B) Phenol resin (C) Polypropylene glycol oligomer having epoxy groups at both ends of the molecular chain. (D) A polypropylene glycol oligomer having amino groups at both ends of the molecular chain. (E) A polyalkylene glycol oligomer represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) [R is an alkylene group with 4 or less carbon atoms, n is 10 to 200
The integers R_1 and R_2 are hydrogen or an alkyl group having 3 or less carbon atoms, and may be the same or different. ]