JP5346463B2 - Semiconductor device using epoxy resin composition for sealing - Google Patents

Description

The present invention relates to a semiconductor device using an encapsulating epoxy resin composition, and more particularly to a low profile quad flat package (LQFP) type semiconductor device .

  Conventionally, ceramics and thermosetting resin compositions are generally used as sealing materials for electronic components such as semiconductor chips. Among them, the epoxy resin composition is an excellent sealing material in terms of the balance between economic efficiency and performance, for example, sealing of surface mount packages that are becoming mainstream as electronic devices become smaller and thinner in recent years. Epoxy resin compositions are widely used as materials (see Patent Documents 1 and 2).

  Semiconductor chip resin sealing in a surface-mount package is achieved by mounting a semiconductor chip on a metal lead frame, electrically connecting the semiconductor chip and the lead frame using a bonding wire, etc., and using a molding die. Generally, the entire chip and a part of the lead frame are sealed with a sealing material such as an epoxy resin composition.

  In addition, a semiconductor device manufactured by sealing a semiconductor chip is usually marked to identify it. As a marking method at this time, ink marking or laser processing is used. Generally applied. However, in recent years, laser marking, which is suitable for mass production and low cost, has become mainstream.

Carbon black is widely used as a colorant for the sealing epoxy resin composition, and it is known that carbon black has good laser marking properties, that is, good color development by laser marking.
JP 2004-156052 A Japanese Patent Laid-Open No. 9-40756

However, in recent years, semiconductor devices have been reduced in size and increased in number of pins, and accordingly, the distance between pitches such as between leads, between pads, and between wires has been reduced. In addition, when a conductive material such as carbon black is used as a colorant in a sealing epoxy resin composition used in a fine pitch semiconductor device having a small distance between pitches, particularly an LQFP type semiconductor device , the semiconductor device Leak failure now occurs.

  In order to prevent this leakage failure, the use of non-conductive substances such as non-conductive carbon as a colorant has been studied. However, when non-conductive carbon is used, laser marking performance and moisture resistance reliability are reduced. There was a problem of doing.

The present invention has been made in view of the circumstances as described above, and is an LQFP type semiconductor device capable of clear laser marking and having a small pitch distance such as between leads, between pads, and between wires. However, an object of the present invention is to provide an LQFP-type semiconductor device using an epoxy resin composition for sealing that does not deteriorate in electrical characteristics and is excellent in moisture resistance reliability.

In order to solve the above problems, an LQFP (Low Profile Quad Flat Package) type semiconductor device of the present invention uses an o-cresol novolac type epoxy resin as an epoxy resin, a phenol novolak resin as a curing agent, and fused silica as an inorganic filler. A semiconductor chip is sealed using an epoxy resin composition for sealing that contains, does not contain carbon black and non-conductive carbon black, and contains an organic azine dye as a colorant. To do.

According to the present invention, since the semiconductor chip is sealed using the sealing epoxy resin composition using an organic azine dye as a colorant, clear laser marking is possible. Furthermore, since carbon black and non-conductive carbon black are not blended, even LQFP type semiconductor devices having a small pitch distance between leads, pads, wires, etc. have good electrical characteristics, and Excellent moisture resistance reliability.

  Hereinafter, the present invention will be described in detail.

  In the present invention, any epoxy resin can be used without particular limitation as long as it has two or more epoxy groups in one molecule. Specific examples of such an epoxy resin include an o-cresol novolac type epoxy resin, a biphenyl type epoxy resin, a triphenylmethane type epoxy resin, a bromine-containing epoxy resin, and an epoxy resin having a naphthalene ring. These may be used alone or in combination of two or more.

  In the present invention, a curing agent having a phenolic hydroxyl group is preferably used as the curing agent. Examples of the curing agent having a phenolic hydroxyl group include polyhydric phenol compounds and polyhydric naphthol compounds. Specific examples of the polyhydric phenol compound include phenol novolac resin, cresol novolac resin, phenol aralkyl resin, biphenyl aralkyl resin and the like. Specific examples of the polyvalent naphthol compound include naphthol aralkyl resins. These may be used alone or in combination of two or more.

  The compounding amount of the curing agent having a phenolic hydroxyl group is preferably such that the equivalent ratio of the phenolic hydroxyl group to the epoxy group (OH equivalent / epoxy equivalent) is 0.5 to 1.5, more preferably equivalent. The amount is such that the ratio is 0.8 to 1.2. When the equivalence ratio is out of the range, the curing characteristics of the epoxy resin composition for sealing may decrease, or the moisture resistance after molding may decrease.

  A hardening accelerator can be mix | blended with the epoxy resin composition for sealing of this invention. Specific examples of such a curing accelerator include imidazoles such as 2-methylimidazole and 2-phenylimidazole, organic phosphines such as triphenylphosphine, tributylphosphine, and trimethylphosphine, 1,8-diazabicyclo (5,4 , 0) Tertiary amines such as undecene, triethanolamine and benzyldimethylamine. These may be used alone or in combination of two or more.

  As for the compounding quantity of a hardening accelerator, 0.1-5 mass% is preferable with respect to the total amount of an epoxy resin and a hardening | curing agent. When the blending amount of the curing accelerator is too small, the curing promoting action may be insufficient, and when the blending amount of the curing accelerator is excessive, the curing characteristics may be deteriorated.

  In the present invention, any suitable inorganic filler can be used without particular limitation, and specific examples thereof include fused silica, crystalline silica, alumina, silicon nitride and the like. These may be used alone or in combination of two or more.

  The blending amount of the inorganic filler is preferably 60 to 93% by mass with respect to the total amount of the epoxy resin composition for sealing. If the amount of the inorganic filler is too small, characteristics such as thermal conductivity and coefficient of thermal expansion may be deteriorated. On the other hand, if the blending amount of the inorganic filler is excessive, the fluidity at the time of molding and the mold filling property may be lowered.

  In the present invention, an organic azine dye is used as a colorant. Here, azine is a generic term for two or more heteroatoms in a six-atom heterocycle, and one of them is a nitrogen atom. The organic azine dye used in the present invention is a compound having one or more azine rings. A commercially available dye can be used as such an organic azine dye.

  The compounding amount of the organic azine dye is preferably 5% by mass or less, more preferably 0.2 to 5% by mass with respect to the total amount of the epoxy resin composition for sealing. If the amount is too small, the color developability at the time of laser marking is deteriorated. On the other hand, if the blending amount is excessive, curability is lowered, and moldability may be adversely affected.

  In the sealing epoxy resin composition of the present invention, components other than those described above can be blended within a range not impairing the effects of the present invention. Specific examples of such components include mold release agents such as stearic acid, montanic acid, montanic acid ester, and phosphoric acid ester, silane coupling agents such as mercaptosilane, glycidoxysilane, and aminosilane, and antimony trioxide. Examples include flame retardants and silicone flexible agents.

  The epoxy resin composition for sealing of the present invention is sufficiently uniform using a mixer, blender, etc. by blending the above epoxy resin, curing agent, inorganic filler, organic azine dye, and other components as necessary. And then melted and mixed in a heated state using a hot roll or a kneader, cooled to room temperature, and then pulverized. In addition, in order to make handling easy, the epoxy resin composition for sealing of the present invention may be a tablet having dimensions and mass that meet molding conditions.

  The semiconductor device of the present invention can be manufactured by sealing a semiconductor chip using the sealing epoxy resin composition obtained as described above. For this sealing, conventionally used molding methods such as transfer molding, compression molding and injection molding can be applied.

  When applying transfer molding, for example, after placing a lead frame mounted with a semiconductor chip such as an IC chip or LSI chip in a cavity of a molding die, the cavity is filled with an epoxy resin composition for sealing and heated. By curing underneath, a semiconductor device in which the semiconductor chip is sealed with the sealing epoxy resin composition can be manufactured.

  When transfer molding is applied, for example, a mold temperature of 170 to 180 ° C. and a molding time of 30 to 120 seconds can be set. However, the mold temperature, the molding time, and other molding conditions are determined by the epoxy resin composition for sealing. What is necessary is just to change suitably according to the compounding composition of a thing.

  As a specific example of the semiconductor device of the present invention, a semiconductor chip is fixed on a lead frame, and after connecting a terminal portion of a semiconductor chip such as a bonding pad and a lead portion of the lead frame by wire bonding or bump, the present invention DIP (Dual Inline Package), PLCC (Plastic Leaded Chip Carrier), QFP (Quad Flat Package), SOP (Small Outline Package), which is sealed by transfer molding using an epoxy resin composition for sealing, Examples include SOJ (Small Outline J-lead package), TSOP (Thin Small Outline Package), TQFP (Thin Quad Flat Package), and LQFP (Low Profile Quad Flat Package).

  Since the epoxy resin composition for sealing of the present invention does not contain carbon black and non-conductive carbon black, even if the distance between the pitches such as between the leads, between the pads, and between the wires is small, the electrical characteristics are good. It does not decrease, and since an organic azine dye is used as a colorant, it is excellent in moisture resistance reliability.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In addition, the compounding quantity shown in Table 1 represents a mass part.

  Each compounding component shown in Table 1 is blended in the proportions shown in Table 1, mixed for 30 minutes with a blender, homogenized, kneaded and melted with a kneader heated to 90 ° C., extruded, cooled, and then predetermined with a pulverizer. By crushing to a particle size, a granular epoxy resin composition for sealing was obtained.

The following evaluation was performed about the epoxy resin composition for sealing of obtained Examples 1-3 and Comparative Examples 1-3.
[Laser marking properties]
A DIP-16 pin molded product obtained by molding at a temperature of 175 ° C. using the epoxy resin composition for sealing was laser-marked, and the printability was visually confirmed. For the marking, a CO ₂ laser (wavelength 10.6 μm, laser output 15 W) and a YAG laser (wavelength 1.06 μm, laser output 10 W) were used.
[Moisture resistance reliability]
A DIP-16 pin molded product sealed with an epoxy resin composition for sealing using a 3 μm aluminum wiring TEG (Test Element Group: test semiconductor chip) under the conditions of 130 ° C., 85 RH%, 30 V The moisture resistance reliability was evaluated by the elapsed time until a defect occurred in the aluminum wiring of the TEG.
[Electrical properties]
The presence or absence of leakage current in LQFP-208 pin (28 mm × 28 mm) sealed with an epoxy resin composition for sealing was confirmed.

  The evaluation results are shown in Table 1.

From Table 1, in Examples 1 to 3 in which an organic azine dye was blended as a colorant and carbon black and non-conductive carbon black were not blended, when either CO ₂ laser or YAG laser was used Also, the laser marking property was good and the moisture resistance was also reliable. Moreover, no leakage current was observed.

  On the other hand, in Comparative Example 1 in which carbon black was blended as a colorant, a leak current was generated in LQFP.

  Further, in Comparative Example 2 in which non-conductive carbon black was blended as a colorant, the laser marking property was poor, and the moisture resistance reliability was greatly reduced.

Although formulated with organic azine dyes, in Comparative Example 3 was blended non conductive carbon black together, CO ₂ laser marking is poor, further moisture resistance reliability is lowered.

Claims (1)

O-cresol novolac epoxy resin as epoxy resin, phenol novolac resin as curing agent, fused silica as inorganic filler, carbon black and non-conductive carbon black are not contained, and organic azine dye is used as colorant A semiconductor device of an LQFP (Low Profile Quad Flat Package) type, wherein a semiconductor chip is sealed with an epoxy resin composition for sealing containing