JPS5875857A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To improve the moisture resistance and high temperature electric characteristics of a resin-sealed semiconductor device by mixing novolac phenol resin organic phosphine compound and boric acid ester compound as hardener of a novolac epoxy resin with novolac epoxy resin. CONSTITUTION:A resin which covers a semiconductor element is produced by mixing novolac epoxy resin containing 170-300 of epoxy equivalent, and further employing novolac epoxy resin and mixing as hardener a novolac phenol resin having a softening point of 60-120 deg.C and less than 3wt% of water soluble phenol resin content at an ambient temperature. Further, the reaction mixture of organic phosphine compound and boric acid ester compound is added as a hardener accelerator to improve the moisture resistance and high temperature electric characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin-sealed semiconductor device with a lid, and more particularly, the present invention relates to a resin-sealed semiconductor device with excellent temperature resistance and high-temperature electrical characteristics.

Resin-sealed lid semiconductor device company, e.g. integrated circuit (IC),
In order to protect semiconductor elements such as large-scale integrated circuits (L8I), transistors, and diodes from external air and mechanical shock, they are sealed with thermosetting resin. Traditionally, the device sealing technology used was Vermechita sealing, which uses wood, metal, seven-piece wood, etc.
Recently, resin encapsulation has become mainstream because it is economically advantageous.As such resin for semiconductor encapsulation, low-pressure molding epoxy, which can be used in low-pressure transfer molding method suitable for mass production, is used. Resin compositions are generally widely used. However, for example, the conventional resin-encapsulated semiconductor device obtained by transfer molding an epoxy resin composition consisting of a synthetic resin, a resin-type phenolic resin curing agent, an imidazole curing accelerator, etc. There are some drawbacks. In other words, (υ) Aluminum electrodes deteriorate due to corrosion due to poor moisture resistance, (2) The functionality of semiconductor devices deteriorates due to poor electrical properties at high temperatures, and in particular increases in leakage current. Among these, (1) K'')--is used or stored in a high-concentration, high-temperature atmosphere, so under such conditions Reliability must also be guaranteed.Reliability evaluation tests for moisture resistance quality assurance include testing at 85°C or 120°C.
An accelerated evaluation method involving exposure to saturated water vapor at ℃ was conducted.
・Recently, evaluation tests have been conducted on bias-applied pears, which further improve acceleration by applying voltage.

However, in a resin-encapsulated semiconductor device using a NIXY resin composition, since the encapsulating resin is wet, moisture can be absorbed from the external atmosphere through the encapsulating resin layer or between the encapsulating resin and the lead frame. penetrates into the interior through the interface and reaches the surface of the semiconductor element.

As a result of the action of this moisture and impurities present in the sealing resin, resin-sealed semiconductor devices develop defects due to corrosion of aluminum electrodes, wiring, etc. Also, when a bias voltage is applied, Due to its electrochemical action, failures due to corrosion of aluminum electrodes and wiring occur particularly frequently.

Next, to explain (2) quickly, since resin-sealed semiconductor devices are sometimes used under high temperature conditions, reliability must be guaranteed even under such conditions. An evaluation test for this purpose is generally an accelerated test in which a bias voltage is applied at 80° C. to 15 G° C. to evaluate reliability.

Such tests (for example, devices with a MOII II structure in which the d1 semiconductor surface is sensitive to external charges, or devices with a PN junction to which a reverse/solar bias is applied) are particularly susceptible to frequent failures. There is a phenomenon in which the leakage current due to the car cylinder increases.It is said that an electric field acts on the sealing resin layer that is in contact with the surface of the element to which voltage is applied.
It is thought to be a turtle that occurs in Yosho.

Since conventional resin-sealed semiconductor devices have the above-mentioned drawbacks, improvements have been sought. The present invention has been made in an attempt to eliminate such drawbacks.
The purpose is to provide a resin-sealed semiconductor device having excellent moisture resistance and high-temperature electrical properties.

In order to achieve the above object, the present inventors have repeatedly addressed the research institute and found that the curing accelerator such as imidazole is the main factor causing the above defect.

Then, they discovered that the moisture resistance and high-temperature electrical properties of semiconductor devices were improved by using the following polyurethane resin composition as a molding material for resin bodies that encapsulate semiconductors, and thus developed the present invention. ◎ That is, the resin-sealed semiconductor device of the present invention is a resin-sealed semiconductor device comprising a semiconductor element and a resin-sealed body covering the semiconductor element. The stopper is a resin composition in which the stopper contains (a lactic acid resin having an equivalent weight of 170 to 300), a phenolic resin, an organic phosphine compound, and a boric acid ester compound. The present invention will be explained in more detail below.

The resin composition according to the present invention consists of the following.

The nixy resin used in the present invention can be any type of lac-type epoxy resin with a nixy equivalent of 170 to 300. For example, a phenolic lac-type epoxy resin can be used. , Cresol no lac moat epoxy resin, hashigunated phenol?
Lac-based Nyxy resin is mentioned. Such Nyxy resin can be used alone or in combination of two or more types, and furthermore, other epoxy resins may be mixed with these resins. - Other epoxy resins include, for example:
Bisphenol-type epoxy resin, abbreviated glycidyl ether, and glycidyl ester-type epoxy resin,
Dalicidylacene-type nixy resin, linear aliphatic nixy resin, alicyclic 1? 1111□ selected from these include oxy resin, elemental formula 1I oxy resin, Harigun Kako 1 oxy resin, etc.: 1111□: Species or F12 or more types are added to Norac ■Ko/' oxy resin, It can be blended in an amount of 50% by weight or less. In addition, the Nixy resin used in the present invention contains less than 10 ppm of chlorine ions, and hydrolyzable chlorine, since chlorine remaining in the resin is one of the causes of corrosion and deterioration of aluminum electrodes. a O, 1 weight -
The following are desirable.

In the present invention, %/h''C curing agent is used as a curing agent.
-2 tylphenol 7 lac resin, nonyl phenol lac resin, etc., and 1 selected from these
A species or two or more species may be used. Considering the workability such as fluidity at the time of construction, it is preferable that the softening point is within the range of 60 to 120°C, and the low molecular weight phenol component is Since this causes poor resin properties qa*, it is preferable that the amount of the water-soluble Fe and Nol resin components at room temperature is 3 parts by weight or less.

It is desirable that the blending amount of the phenolic resin be selected appropriately based on the relationship with the amount of phenolic groups in the epoxy resin, and the number of phenolic hydroxyl groups in the phenolic resin and the phenolic group in the epoxy resin. The ratio of numbers is in the range 0.5 to 1.5! IK is desirable.

If the ratio of phenolic water groups/functional foxy groups exceeds 0.5 droplets or Fil, 5, one reaction will not proceed sufficiently;
The properties of the cured product deteriorate.

The organic phosphine compound used in the present invention has a function as a curing accelerator, and by incorporating such a compound, the moisture resistance and high temperature electrical properties of the semiconductor device are improved.

Such an organic phosphine compound has the following general formula [wherein at, Re and Km h may be the same or different, a hydrogen atom, an alkyl group, a phenyl group]
An aryl group such as a lyl group, an abbreviation for a cyclohexyl group, an abbreviation for an alkyl group (in the formula, R'a represents an alkane, and R' and R' may be the same or different, and a hydrogen atom, an alkyl represents an aryl group such as a phenyl group, a tolyl group, or a cycloalkyl group such as a cyclohexyl group (excluding cases where R' and R11' are hydrogen atoms). It may be a group, except when R, R, and R are all hydrogen atoms.
For example, tertiary phosphine compounds such as triphenylphosphine, Ritchl's sphine, tricyclohexylphosphine, and methyldiphenylphosphine, secondary phosphine compounds such as butylphenylphosphine and diphenylphosphine, and primary phosphine compounds such as 7erphosphine and octylphosphine. chemical compounds, and bis()7-elphosphino)methane, 1,2-bis()phenylphosphino)
Tertiary bisphosphine compounds such as ethane are mentioned, and 1m selected from the group consisting of these! Two or more types of i[L< are used.

Among these, it is preferable to use arylphosphine compounds, with syarylphosphines such as triphenylphosphine being most preferable.

Such organic phosphine compounds are It is preferably blended in an amount of 0.001 to 20% by weight, particularly preferably 0.0
The boric acid ester compound L1 used in the present invention improves the temperature resistance and high-temperature electrical properties of semiconductor devices by interacting with the organic phosphine compound, compared to when the organic phosphine compound is used alone. It is added for the purpose of further improvement.

As such a boric acid ester compound, the following general formula CI) ~ [■] (RO)aB ct] (in the formula, it,
R may be the same or different, and each unit may be the same or different; an alkyl group; when at least one hydrogen atom of the alkyl group is substituted with a water group Xyalkyl group; Shita alkyl group such as hexyl group; Aryl group such as phenyl group, Fyl group, naphthyl group; Hydroxyaryl group such as hydroxyphenyl group & Nido oxytolyl group; p group such as benzyl group It represents a dynamic I group, etc., and is an integer of h company. ) and polyboric acid ester compounds having one boron atom in one molecule and polyboric acid ester compounds having two or more boron atoms in one molecule.

Examples of the above-mentioned boric acid ester compounds include trimethyl borate, sylethyl borate, triisopropyl borate, silybutyl borate, Y-lycyclohexyl borate, cyaninyl borate, tritalesyl borate, boric acid! Silinonylphenyl, trinaphthyl borate, tribenzyl borate, fmonmethyl borate, l isoptapyr liporate, l butyl liporate, polyborate lI7 el, talesyl borate, 4 hensyl borate, dihexylenda 9 colpai is ray Y% FiZ or one selected from the group consisting of
More than seeds are used.

It is preferred that the boric acid ester compound is blended in an amount of 0.01 to 10% by weight based on the total amount of the nixy resin and phenol resin. The inorganic filler includes an inorganic filler and various additives, and examples of the inorganic filler include quartz glass powder,
Examples include crystalline silica powder, glass fiber, talc, alumina powder, calcium silicate powder, calcium carbonate powder, barium sulfate powder, magnesia powder, and one or more selected from the group consisting of these. used. Among these, it is preferable to use quartz glass powder and crystalline silica powder because they have high purity and a low coefficient of thermal expansion. It is necessary to select the filler appropriately depending on the type of inorganic filler 1IiK, but for example, when used in -transfer molding, the weight ratio is preferably about 1.5 to 4 times the total amount of epoxy resin and phenol resin. In addition, the particle size of the inorganic filler can be appropriately selected and used, and by mixing coarse and fine particles, it is possible to improve moldability.In addition, various additives can be used. For example, natural waxes, synthetic wax chains, metal salts of straight chain fatty acids, acid amides,
Lifting agents such as esters/Darafins, mm agents such as chlorinated Raffin, bromotoluene, he+t-brimbenzene, antisulfur iooxide, car? Depending on the purpose, a coloring agent such as pineapple, a silane coupling agent, etc. may be appropriately added and blended.

The resin composition having the above composition can be prepared as a molding material for semiconductor encapsulation using a conventional method. In addition, it is possible to easily obtain a molding material made of a resin composition by performing a melt mixing treatment using a heated roll or the like, or by performing a mixing treatment using a kneader or the like. .

WcFi mixed with the Nixy resin composition according to the present invention
, each weighed component may be mixed at the same time, but
It is also possible to mix some of the components in advance and then mix this mixture with other components.In the latter case, a particularly preferred embodiment is to use a reaction mixture of an organic phosphine compound and a boric acid ester compound. There is a way.

Such a reaction mixture can be easily obtained by simply mixing an organic phosphine compound and a boric acid ester compound, but if necessary, they may be heated to make them compatible or mixed.
You can also dissolve and mix by adding a solvent ψ.

In the above reaction mixture, the organic phosphine compound and the boric acid ester compound are thought to form a coordination compound, for example, triphenylphosphine and boric acid).
When mixed in equimolar amounts with &i, the compound is thought to form a coordination compound with l=1. However, based on the present invention, Hiro 1. It is not necessarily necessary to mix the above compounds in equimolar amounts, and it is not necessary to mix the compounds in which the coordination compound is formed. A preferred blending ratio of such compounds is about 0.01 to 10 moles of the boric acid ester compound to 1 mole of the organic sphine compound.

In addition, as another preferred embodiment, a mixture obtained by melting a Tumelac type phenol resin, an organic phosphine compound and a boric acid ester compound, or a reaction mixture of an organic phosphine compound and a boric acid ester compound,
There is a method using a molten mixture of phenolic resin.

Such a molten mixture can be easily obtained by dissolving a reaction mixture of an organic phosphine compound and a boric acid ester compound in a lac-type phenolic resin, and if necessary, the mixture can be heated and melted. Even if it is.

An epoxy resin-encapsulated semiconductor device using the above reaction mixture ★ or *m mixture is preferable because more stable characteristics can be obtained.

The resin-sealed semiconductor device of the present invention uses a molding material made of the above-mentioned epoxy resin composition, for example, for IC, LSI, etc.
,) It can be manufactured by sealing semiconductor devices such as transistors, Nyristors, and diodes. Such a sealing method may be a generally adopted method, such as a low-pressure transformer 7°f molding method, an injection molding method, a compression molding method, a gluing method, etc., among which 1. Preferably, a low pressure transfer molding method is used. Furthermore, special encapsulation methods such as solvent IWT* can be used to coat the semiconductor surface with a non-solvent composition, or to locally encapsulate the semiconductor surface as part of a gasket. be. When curing the sealing resin, 111)0
It is preferable to cure at a temperature of ℃ or more. Silica acid 7EL:19 (1 (1 mol)) was placed in a flask and melted by heating to form a homogeneous liquid.

The liquid was then cooled to yield an equimolar reaction mixture of tri7erphosphine and triphenyl borate.

Examples 1-3 Epoxy l1llWI! Cresol having an epoxy equivalent weight of 220 is a lac-type epoxy resin (epoxy m
1ll! A) and an odorous epoxy novolak resin (epoxy resin B) having an epoxy equivalent weight of 290 were used, a 7E/-crucible rank resin having a molecular weight of 800 was used as a curing agent, tri7Eerphosphine was used as an organic phosphine compound, and a boric acid ester compound was used. Using triphenyl borate and the equimolar reaction mixture of triphenylphosphine and triphenyl borate obtained in the synthesis example, 1 quartz glass powder (inorganic filler), antimony trioxide (I
It is prepared by using the following:
Epoxy resin composition (by weight) as shown in 1.
Runs @1-3) were prepared. At the same time, as comparative examples, five types of turtles were prepared in which an organic phosphine compound or a boric acid ester compound was used alone, or 2-methylimidazole or boron trisulfide monoethylamine complex was used as a curing accelerator. Several preparations were made.

Table 1 The epoxy resin compositions were mixed using a mixer and then kneaded using a heating rail to obtain a molding material.

Transfer molding was performed using the molding material thus obtained, and the MOB type integrated circuit was sealed with resin. For sealing, heat the molding material to 90°C with a high chest wave preheater and heat it to 175°C.
This was carried out by molding at 180°C for 2 minutes and after-curing at 180°C for 3 hours.

Using each of the epoxy resin compositions, 100 resin-sealed semiconductor devices were manufactured using the above method, and the following tests were conducted.

(1) Anti-diaphragm test (bias PCT): IOV was applied in water vapor at 120°C and 2 atm, and the cumulative failure rate (%) of defective products whose aluminum wiring broke due to corrosion was investigated over time. Ta.

(2+ MOS-B T test = When the leakage current value increases to more than 100 times the initial value by applying a drain voltage of 5■ and an offset dart voltage of 5■ to the off-seven point M08FET circuit while open at 100℃) were considered to be defective, and the defect rate (%) of the defective products that occurred was plotted over time.

The results of the moisture resistance test are shown in Table 2, and the results of the MOS-BT test for examining high temperature electrical properties are shown in Table 3.

However, Comparative Example 2 was not cured under the above transfer molding conditions and could not be sealed.

Table 2 Table 3 As is clear from the table, the resin-sealed semiconductor device encapsulated using the polyurethane resin composition of the present invention greatly reduces corrosion of aluminum wiring, etc., and reduces leakage current. It was confirmed that there was no deterioration in the functionality of the semiconductor device due to the increase, and that the moisture resistance and high temperature electrical properties were extremely excellent.

Claims (1)

[Claims] 1. A resin-sealed semiconductor device comprising a semiconductor element and a resin-sealed body covering the semiconductor element, wherein the resin-sealed body has an epoxy equivalent of (&) 110 to 300. (b) novolak lidding I xy resin with novolac hook [1 phenolic resin, (c)
1. A resin-sealed semiconductor device, characterized in that it is a cured product of a polyurethane resin composition containing an organic phosphine compound and (d) a boric acid ester compound. 2. The resin-sealed lid semiconductor device according to claim 1, wherein the epoxy resin composition is a reaction mixture of an organic phosphine compound and a boric acid ester compound. 3. For use as an epoxy resin composition for a WI fusion compound comprising a reaction mixture of an organic phosphine compound and a boric acid ester compound and a rack distilled phenol Wtt - a resin-sealed type according to claim 2 Semiconductor device 04, Claim 1 in which a molten mixture consisting of a Norac type phenol resin, an organic phosphine compound and a boron ester compound is used as the epoxy resin composition.
The resin-sealed semiconductor device described in Section 1. 6. The resin-sealed lid semiconductor device according to claim 1, wherein the epoxy resin composition further contains an inorganic filler.