JP2574434B2 - Semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device that maintains excellent reliability even in a high-temperature and high-humidity atmosphere.

[Conventional technology]

Semiconductor elements such as transistors, ICs, and LSIs are generally made of an epoxy resin composition, and are resin-sealed by transfer molding or the like to form semiconductor devices. However,
With the improvement of integration through technological innovation in the semiconductor field,
For example, surface-mount packages also tend to be smaller and thinner, and the epoxy resin composition, which is a sealing resin, requires higher reliability, especially humidity resistance and storage reliability at high temperatures. It has come to be.

That is, the semiconductor device may be used or stored in a high-temperature and high-humidity atmosphere, and high quality must be ensured even under such conditions. Therefore, for example, as a reliability evaluation test of moisture resistance, a semiconductor device encapsulated with a resin is left at a high temperature of 121 ° C. or 135 ° C. and at a high humidity of 100% or 85% to deteriorate its characteristics. An accelerated test (pre-shock car test) is performed to evaluate the condition, and a test (pre-shock car bias test) in which a voltage is applied under the above-mentioned conditions to enhance the accelerating property is performed.

[Problems to be solved by the invention]

When the semiconductor device is left in such a high-temperature and high-humidity atmosphere, moisture penetrates into the inside from the external atmosphere through the sealing resin layer or through the interface between the sealing resin and the lead frame. May be reached. Then, due to the action of the infiltrated moisture and various impurities present in the sealing resin, the aluminum electrodes and wirings on the surface of the semiconductor element are corroded to cause defective products, and when the voltage is applied as described above, There is a problem that corrosion is promoted by a chemical action and a defective product is generated. Examples of such an impurity that induces corrosion include halogen ions such as chlorine ions and bromine ions.
Since the halogen ion is particularly easily contained in the production process of the epoxy resin, a method for reducing the halogen ion has been studied, and recently, a material having a low impurity content has been obtained. . However,
It is impossible to produce a product containing no impurities. On the other hand, as described above, the degree of integration of the semiconductor is improved, and the size and thickness of the package tend to increase. As a result, the number of electrodes and wiring of the semiconductor device increases, and the water content increases. Therefore, the possibility of occurrence of defective products increases because the path of intrusion into the inside becomes short. For this reason,
There is a demand for the development of a semiconductor device exhibiting high reliability even in a high temperature and high humidity atmosphere.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a semiconductor device having excellent moisture resistance reliability and excellent moisture resistance reliability even when left in a high-temperature atmosphere for a long time.

[Means for solving the problem]

In order to achieve the above object, a semiconductor device of the present invention includes the following components (A) to (D), and has a mixing ratio C / D of 95/5 to 40/60 based on the weight of the C component and the D component. And an epoxy resin composition wherein the blending amount of the C component and the D component (C + D) is set to be 0.5 to 10 parts by weight with respect to 100 parts by weight of the B component. In this case, the semiconductor element is sealed.

(A) Epoxy resin.

(B) Novolak type phenolic resin.

(C) an organic phosphine compound.

(D) boric acid.

[Action]

That is, the present inventors have conducted a series of studies in order to obtain a sealing resin having excellent moisture resistance reliability even when left for a long time in a high-temperature, high-humidity atmosphere. As a result, an organic phosphorus compound which is an organic phosphine compound is obtained. When boric acid is used as a curing accelerator, moisture does not enter the semiconductor device through the sealing resin layer and the like even when left in a high-temperature and high-humidity atmosphere for a long time. The present inventors have found that excellent reliability can be obtained even when left unattended, and have reached the present invention.

The epoxy resin composition used in the present invention comprises an epoxy resin (A component) and a novolak type phenol resin (B
Component), an organic phosphine compound (component (C)) and boric acid (component (D)), and is usually in the form of a powder or tablet.

The epoxy resin as the component A is not particularly limited as long as it is a compound having two or more epoxy groups in one molecule. For example, a bisphenol A type epoxy resin,
Glycidyl ether type epoxy resin such as novolak type epoxy resin composed of various phenols, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, linear aliphatic epoxy resin, cycloaliphatic epoxy resin, or chlorine or bromine in the above epoxy resin And the like, and halogenated epoxy resins into which halogens are introduced, and the like, which are used alone or in combination. Above all, it is preferable to use a novolak type epoxy resin, and particularly those having an epoxy equivalent of 170 to 300 and a softening point of 60 to 110 ° C are suitably used.

Further, as the epoxy resin of the component A, it is preferable to use a resin having a low content ratio of a component which easily generates ionic impurities due to ionic impurities or decomposition, for example, free Na ions or Cl in these epoxy resins. The content of ions is preferably set to 10 ppm or less, and the content of hydrolyzable halogen ions is preferably set to 0.1 wt% or less.
That is, when the content of the halogen ion is out of the above range, a failure of the element due to corrosion tends to occur.

The component B novolak-type phenol resin acts as a curing agent for the epoxy resin of the component A, and includes phenol, cresol, bisphenol A,
It is preferable to use a resin obtained by condensing a phenolic compound such as resorcinol with formaldehyde or the like under an acidic catalyst and having a hydroxyl equivalent of 100 to 150 and a softening point of about 60 to 110 ° C. Further, as the novolak-type phenol resin obtained as described above, a resin in which the content of an uncondensed phenolic compound in the resin is 1% by weight (hereinafter abbreviated as "%") in the novolak-type phenol resin is used. Is preferred. Further, it is preferable to use one having a low content of Na ions, Cl ions and other ionic impurities in view of the effect of improving reliability.

The mixing ratio of the novolak type phenol resin of the component B to the epoxy resin of the component A is such that the hydroxyl group in the phenol resin per equivalent of epoxy group in the epoxy resin is
It is preferable to mix them in an amount of 0.5 to 2.0 equivalents, preferably 0.8 to 1.2 equivalents.

As the organic phosphine compound of the component C,
The second and third phosphine compounds are mentioned, and among them, the third phosphine compound is preferably used. As the third phosphine compound, a triallyl phosphine compound represented by triphenylphosphine is preferably used because of its good stability.

Examples of the boric acid of the component D include orthoboric acid, metaboric acid and tetraboric acid.

The organic phosphine compound of the component C and the boric acid of the component D act as a curing accelerator, and it is preferable to use the two components in advance by mixing them. In this case, the mixing ratio (by weight) of the organic phosphine compound (X) as the component C and the boric acid (Y) as the component D needs to be set so that X / Y = 95/5 to 40/60. That is, if it is outside the above range,
This is because the effect of improving the moisture resistance is not observed, and the curability of the sealing resin is reduced.

The compounding amount of the mixture of the organic phosphine compound of the component C and the boric acid of the component D used as the curing accelerator is determined based on the novolak type phenol resin of the component B as the curing agent.
It is necessary to set the blending ratio of 0.5 to 10 parts with respect to 100 parts by weight (hereinafter abbreviated as "part"), preferably 1.0 to 4.0 parts. That is, if the blending amount of the mixture of the component C and the component D is less than 0.5 part, the curing speed of the sealing resin is reduced, and as a result, the molding workability and the properties of the cured product are reduced. If it exceeds, the curing speed of the sealing resin becomes too fast, and an unfilled portion occurs at the time of resin sealing, which causes molding failure or a part of the sealing resin gels at the time of resin sealing. This causes problems such as the following.

In addition to the components (A) to (D), other additives conventionally used can be appropriately added to the epoxy resin composition used in the present invention, if necessary.

Examples of the other additives include inorganic fillers,
Surface treatment agents for inorganic fillers such as flame retardants and silane coupling agents, release agents, pigments and the like.

Examples of the inorganic filler include silica, alumina, talc, clay, and glass fiber. Among them, it is preferable to use fusible or crystalline silica,
Among them, especially those having a particle size of 150 μm or less, and those containing 50 to 150 μm at a ratio of 10% or less in the inorganic filler are suitably used, and the blending ratio of the inorganic filler with respect to the entire epoxy resin composition is: It is preferable to set within the range of 30 to 80%.

Examples of the flame retardant include antimony oxide, halides, phosphorus compounds and the like.

The epoxy resin composition used in the present invention can be produced, for example, as follows. That is, the above-mentioned A to D component raw materials and the above-mentioned other additives are appropriately blended, sufficiently mixed by a mixer or the like, and the mixture is melt-kneaded by a hot roll machine or the like, or continuously into an extruder. The mixture is cooled and cooled to room temperature, then pulverized by a known means, and, if necessary, tableted, whereby a target epoxy resin composition can be produced. Prior to the above blending, the boric acid of component D is dissolved in a solvent such as methanol in advance and mixed with a heated and melted novolak phenol resin, and then the solvent is removed. To dissolve the boric acid. That is, in order to uniformly cure the epoxy resin composition, it is necessary that the curing accelerator is uniformly mixed, but the boric acid of the D component has low solubility in the resin, and during the melt-kneading of the component materials, This is because it is difficult to sufficiently dissolve and mix, and if the mixing is further performed for a long time, gelation occurs. In addition, since the organic phosphine compound of the component C has high solubility in a resin,
The organic phosphine compound is previously converted to B as in the case of boric acid.
The component may or may not be dissolved in the novolak type phenol resin.

The sealing of the semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by a known molding method such as ordinary transfer molding.

The semiconductor device obtained in this way has excellent moisture resistance reliability when left at high temperature and high humidity.

〔The invention's effect〕

As described above, the semiconductor device of the present invention is sealed using the special epoxy resin composition containing the organic phosphine compound (C component) and the boric acid (D component) as curing accelerators. Due to the action of the component C and the component D, the intrusion of moisture is prevented even when the resin is left in a high-temperature and high-humidity atmosphere for a long time, so that the resin has excellent moisture resistance reliability when left at high temperature and high humidity. ing.

 Next, examples will be described together with comparative examples.

[Examples 1 to 4 and Comparative Examples 1 to 4] Raw materials as shown in Table 1 below are prepared, and first, triphenylphosphine and boric acid used as a curing accelerator are previously heated and melted at 150 to 160 ° C. The obtained novolak type phenolic resin was blended in the ratio shown in the same table, sufficiently dissolved, cooled, and then pulverized. The pulverized product and the remaining raw materials were blended in the proportions shown in the same table, kneaded by a heating roll machine, cooled, and then pulverized to obtain a desired powdery epoxy resin composition. In addition, γ-glycidoxypropyltrimethoxysilane was used as the silane coupling agent in Table 1.

Next, using the powdered epoxy resin composition obtained as described above, under a condition of 170 ° C. × 2 minutes, a semiconductor element made of a silicon chip having aluminum wiring deposited on its surface is sealed by transfer molding. And 16 pins
DIP type semiconductor devices were obtained. Further, the obtained semiconductor device was after-cure at 170 ° C. × 5 hours. The semiconductor device is applied with a voltage of 20 V in a bath at 130 ° C. and 85% RH to check the disconnection failure due to aluminum corrosion.
BT test)> and the results are shown in Table 2 below.

From the results in Table 2 above, it can be seen that the example product is superior to the comparative product in the results of the long-term PCBT test, and thus has significantly improved humidity resistance in a high-temperature and high-humidity atmosphere. .

Claims (3)

(57) [Claims] 1. A composition comprising the following components (A) to (D), wherein the mixing ratio C / D based on the weight of the C component and the D component is set to 95/5 to 40/60, and the C component And D component (C +
A semiconductor device in which a semiconductor element is sealed with an epoxy resin composition in which D) is set in a proportion of 0.5 to 10 parts by weight with respect to 100 parts by weight of a B component. (A) Epoxy resin. (B) Novolak type phenolic resin. (C) an organic phosphine compound. (D) boric acid. 2. The semiconductor device according to claim 1, wherein the organic phosphine compound of the component C and the boric acid of the component D are dissolved in the novolak phenol resin of the component B in advance. 3. A composition comprising the following components (A) to (D), wherein the mixing ratio C / D based on the weight of the C component and the D component is set to 95/5 to 40/60, and the C component: And D component (C +
An epoxy resin composition for semiconductor encapsulation wherein D) is set to be in a proportion of 0.5 to 10 parts by weight with respect to 100 parts by weight of the B component. (A) Epoxy resin. (B) Novolak type phenolic resin. (C) an organic phosphine compound. (D) boric acid.