JPS62224051A - Resin sealed semiconductor device - Google Patents

Abstract

PURPOSE:To improve moisture resistance after solder dip, by coating the surface of a semiconductor element with specified polyorganosiloxane. CONSTITUTION:The surface of a semiconductor element is coated with at least one of polyorganosiloxane shown by formula I and polyorganosiloxane shown by formula II. In these formulae I and II, notations are as follows; R represents methyl group, R1 is (CH2)l (where l=1-3, integer), A is one of amino group, epoxy group, carboxyl group, by hydroxyl group and cyclohexane oxide group, (m) is an integer of 1-300, (n) is 0 or an integer of 1-300 (where m+n=1-500, integer), and (x) is an integer of 10-300. Thereby adhesive property to resin seal is remarkably improved, and permeation of moisture into the boundary between the semiconductor element and the resin seal is prevented, so that moisture resistance after solder dip is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin-sealed semiconductor device that has excellent reliability after being dipped in solder.

[Conventional technology]

Traditionally, the dual in-line package (DIP) type, which is a resin-sealed semiconductor device in which semiconductor elements such as transistors, ICs, and LSIs are protected by a plastic package, has been awarded an award. It's been a month.

However, in recent years, with the trend of development of small, high-performance products such as wristwatches, calculators, and VTR cameras, there has been a demand for higher-density packaging and thinner semiconductor devices, and so-called flat package type surface-mount semiconductor devices are often used. This is becoming more and more common.

The above-mentioned surface mount type semiconductor device is not one in which only the lead pins are partially immersed in solder as in conventional DIP type devices, but the entire semiconductor device is usually immersed in a solder bath at 260°C and then connected to a printed circuit board. It is implemented by fixing it.

[Problem that the invention seeks to solve]

However, when the entire semiconductor device is immersed in a solder bath as described above, the semiconductor device undergoes a rapid temperature change from room temperature to 260 degrees Celsius, which causes a gap between the lead frame and the sealing resin due to thermal shock, causing the package to deteriorate. moisture resistance is impaired.

Therefore, in order to meet the demands for thinner semiconductor devices and higher density packaging, there has been a strong desire to improve the moisture resistance of the package.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a resin-sealed semiconductor device that has excellent moisture resistance after being immersed in solder.

[Means for solving problems]

In order to achieve the above object, the resin-sealed semiconductor device of the present invention is a resin-sealed semiconductor device in which a semiconductor element is encapsulated with a resin composition, and the surface of the semiconductor element is expressed by the following formula (1). ) and at least one of the polyorganosiloxanes shown in (H) below.

Note that the above-mentioned "surface of the semiconductor element" includes not only the literal front surface but also outer surface metals such as the back surface and side surfaces.

That is, in order to improve the moisture resistance of a resin-sealed semiconductor device after being immersed in solder, the present inventors first conducted research to elucidate the factors that reduce the moisture resistance of the package. As a result, moisture absorbed into the semiconductor device during the semiconductor device manufacturing process or post-product storage process remains mainly at the interface between the semiconductor element and the sealing resin.
The high temperature (240°C or higher) during solder dipping causes rapid evaporation into high-pressure steam, which creates gaps at the interface between the semiconductor element and the encapsulating resin, and cracks in the package. It was found that the moisture resistance of the package decreased.

Therefore, the present inventors conducted a series of further studies on methods for removing moisture remaining in the semiconductor device or methods for preventing moisture absorption in advance, and as a result, the surface of the semiconductor element was coated with the above specific silicone oil. When treated, the surface of the semiconductor element itself has the effect of significantly improving adhesion to the encapsulating resin due to the reaction between the functional groups in the silicone oil and the epoxy groups in the encapsulating resin, thereby improving the bond between the semiconductor element and the encapsulating resin. This invention was achieved by discovering that it is possible to prevent moisture from entering the interface and to improve moisture resistance after immersion in solder.

The resin-sealed semiconductor device of the present invention includes a semiconductor element whose surface is treated with the above-mentioned specific silicone oil, and a resin composition for sealing this semiconductor element.

As the silicone oil, at least one of polyorganosiloxanes represented by the following general formula CI) and the following general formula (n) is used.

(Space below) The silicone oil represented by the above general formulas (1) and [II] must have an amino group, an epoxy group, a carboxyl group, etc. that exhibit reactivity with epoxy groups in its molecular structure, Therefore, in formula (r), m is always set to 1 or more.

The above-mentioned silicone oil generally has a viscosity of 300 to 400 cps at 25°C, and representative examples include the following.

The silicone oils listed above may be used alone or in combination. Especially when used together,
Silicone oil represented by general formula (1) and general formula [■
] Setting the silicone oil represented by 5 so that the former is 5 and the latter is 1 brings about good results. In the silicone oil in the above general formula (I), the repeating units corresponding to the number of repeats m and the repeating units corresponding to the number n of repeats may be random or alternate, or may have a block shape. There is no problem even if it is.

By using the above-mentioned silicone compound, the water repellency of the silicone compound itself, the affinity for semiconductor elements of the silicon atom of the silicone compound, and the epoxy group of the encapsulating resin of the functional group in its molecular structure can be improved. The surface of the semiconductor element becomes water repellent due to the reactivity with the encapsulating resin, and at the same time, the adhesion with the encapsulating resin is significantly improved, preventing moisture from entering the interface between the semiconductor element and the encapsulating resin. It becomes wet.

The resin composition used for encapsulating the semiconductor element whose surface has been surface-treated as described above is obtained using a thermosetting resin, a hardening agent, a filler, a pigment, etc., and is usually in powder form or in powder form. It is in the form of a compressed tablet.

As the thermosetting resin, epoxy resins are preferably used, including phenol resins and urea resins.

Melamine resin, polyester resin, diallyl phthalate resin, polyphenylene sulfide, etc. can be used in place of all or part of the above epoxy resin.

Bisphenol A type epoxy resin.

Any known epoxy resins such as glycidyl ether type epoxy resins such as phenol novolac type and talesol novolac type, alicyclic epoxy resins, and halogenated epoxy resins may be used, but in particular, phenol novolac or cresol novolac type epoxy resins may be used. Preferred for use. Further, among these epoxy resins, those having a chlorine ion content of 10 ppm or less and a hydrolyzable chlorine content of 0.1% by weight or less (hereinafter abbreviated as "%") are suitable.

Examples of curing agents for the epoxy resin include novolak type phenolic resins (phenol novolak, cresol novolak, etc.), acid anhydride curing agents (tetrahydrophthalic anhydride, trimellitic anhydride 1 benzophenone tetracarboxylic anhydride, etc.), Amine (diaminodiphenylmethane,
metaphenylene diamine, diaminodiphenyl ether, etc.) are used. In particular, phenolic resins such as phenol, cresol, xynol, resorcinol,
Preferred are those obtained by reacting one or more of phenylphenol, bisphenol A, etc. with formaldehyde, paraformaldehyde, etc. in the presence of an acid catalyst. These curing agents are preferably blended in an amount of 0.5 to 1.0 equivalents per equivalent of the thermosetting resin.

Furthermore, in addition to the above-mentioned curing agent, heterologous imidazole compounds such as 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, and 2-methylimidazole, and 1,8-diaza-bicyclo(5,4 , O) A curing accelerator such as undecene-7 and its salt, an organic tertiary phosphine compound such as l-riphenylphosphine, etc. can also be blended.

Note that the above composition may contain conventionally used inorganic fillers, flame retardants, mold release agents, pigments, etc., as necessary.

The resin composition used in the present invention can be produced using the above-mentioned raw materials, for example, in the following manner. That is, the resin exemplified above, a curing agent, pigment, and other additives are appropriately blended, and this mixture is kneaded in a heated state using a kneading machine such as a mixing roll machine to form a semi-cured resin composition, which is then heated at room temperature. After being cooled to 100%, the powder is pulverized by known means, and produced as is or by tabletting if necessary.

The resin-sealed semiconductor device of the present invention can be manufactured using the resin composition as described above and the silicone oil, for example, in the following manner.

That is, first, on the surface of the semiconductor element to be sealed,
It can be obtained by spraying, spraying, or immersing a semiconductor element in the silicone oil, and then sealing the semiconductor element with the resin composition. Sealing of the semiconductor element is not particularly limited, and can be performed by a conventional method, for example, a known molding method such as transfer molding.

In the resin-sealed semiconductor device obtained in this way, the surface of the semiconductor element is modified to have (θ aqueous and adhesive properties) by silicone treatment before resin encapsulation, so that moisture does not form at the interface between the semiconductor element and the encapsulation resin. Therefore, when the semiconductor device is immersed in solder, high-pressure steam is not generated at the interface between the semiconductor element and the sealing resin, and no gaps are generated at the interface or cracks are generated in the package.

〔Effect of the invention〕

As described above, the surface of the resin-sealed semiconductor device of the present invention is treated with silicone oil. 8.Using a special semiconductor element that has been modified for water resistance and adhesion, moisture does not enter the interface between the semiconductor element and the sealing resin, and the moisture resistance does not deteriorate even after being immersed in solder, making it an extremely reliable product. It is highly sexual.

Furthermore, since the resin-sealed semiconductor device of the present invention does not allow moisture to enter the interface between the semiconductor element and the encapsulation resin, it has the effect of improving moisture resistance to a certain extent even when applied to any type of semiconductor device. However, it can be said that it is particularly suitable to apply it to a surface-mounted semiconductor device because it eliminates the conventional problem of deterioration in moisture resistance after solder immersion.

Next, Examples will be explained along with Comparative Examples and A)1.

[Examples 1 to 8] A linear IC was prepared as a semiconductor element, and on its surface,
Surface treatment was performed by spraying a diluted solution prepared by diluting silicone oil represented by the following general formulas (1) and [II] and according to Table 1 below 10 times with toluene.

(Margin) (hereinafter referred to as margin) As shown in the table above, Examples 1 to 6 were surface treated with one type of silicone oil, and Examples 7 and 8 were treated with two types of silicone oil.
The surface is treated with a mixture of different types of silicone oil.

Next, the semiconductor element surface-treated as described above was transfer-molded at 175°C for 2 minutes using the raw materials shown in Table 2 below, and molded into an 8-bin small outline (SOP-8) mold. This resin-sealed semiconductor device was made into a resin-sealed semiconductor device.

L2" (!1ffi @B) [Comparative Example 1] In place of the above silicone oil, the following general formula % formula % (
) [ Silicone oil that does not have the functional group shown was used. Other than that, a resin-sealed semiconductor device was obtained in the same manner as in the above example.

[Comparative Example 2] The following general formula [■] R+Si was used as silicone oil.
O Car R...(IV) (OC-1)g-→-0C1)1) A silicone oil having a functional group that does not react with the epoxy group of the sealing resin was used. Other than that, a resin-sealed semiconductor device was obtained in the same manner as in the above example.

[Comparative Example 3] No surface treatment with silicone oil was performed on the surface of the semiconductor element. Other than that, a resin-sealed semiconductor device was obtained in the same manner as in the above example.

The actual height measurement and comparative height measurement obtained in this way are
After being placed in a C295%R1) atmosphere for 20 hours to absorb moisture, it was immersed in a 260°C solder bath for 10 seconds. In addition to examining the presence or absence of cracks after solder immersion, we conducted a reliability test using a pressure cooker (121°C, 100%
PCT test at RH) was performed. The results are shown in Table 3 below.

(The following is a margin) Table 3 - From the above results, it can be seen that the actual height measurement is significantly superior in moisture resistance after solder immersion compared to the comparative height measurement.

In other words, unlike comparative height measurements, actual height measurements are surface-treated with silicone oil that has functional groups that can react with epoxy resins and phenol resins, so they have extremely high moisture resistance even after being immersed in solder. I know that there is.

Claims (1)

[Claims] (1) A resin-sealed semiconductor device in which a semiconductor element is encapsulated with a resin composition, wherein the surface of the semiconductor element is a polyorganosiloxane represented by the following formula [I] and a polyorganosiloxane represented by the following formula [II]. ] A resin-sealed semiconductor device characterized by being coated with at least one of the polyorganosiloxanes shown in the following. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[II] In the above formulas [I] and [II], R is a methyl group, and R_1 is a methyl group. (CH_2)_l (where l = an integer of 1 to 3), A is an amino group, epoxy group, carboxyl group, hydroxyl group, or cyclohexene oxide group, m is 1 to 30
An integer of 0 and n is an integer of 0 or 1 to 300 (however, m+n
= an integer of 1 to 500), x is an integer of 10 to 300.