JPH09194689A - Epoxy resin composition for semiconductor sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing resin composition improved in marketability with YAG laser or carbon dioxide laser beams by mixing an epoxy resin with a phenolic resin curing resin, a cure accelerator, an inorganic filler, carbon black, and mica. SOLUTION: This composition essentially consists of an epoxy resin, a phenolic resin curing agent, a cure accelerator, an inorganic filler, carbon black having a means particle diameter of 5-150nm in a state of primary particles, and mica (K2 O.3Al2 O3 .6SiO2 .2H2 O). The amount of the mica used is desirably 0.02-2wt.% based on the whole composition. This composition can give semiconductor packages highly markable with YAG or carbon dioxide laser beams which give marks of high contrast without causing the packages to produce much soot and therefore it can contribute to the improvement of productivity and the reduction of production cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation having good marking characteristics with a YAG laser or a carbon dioxide gas laser.

[0002]

2. Description of the Related Art Epoxy resin-based resin compositions for semiconductor encapsulation have been developed and produced in order to protect semiconductor bodies from mechanical and chemical effects. Items required for this differ depending on the structure of the semiconductor package to be sealed. For example, a semiconductor package surface has conventionally been printed with an ink mark such as a product number. Recently, however, laser marking has been increasingly used for low cost and quick delivery. Compared with ink marking, laser marking is said to have the following features. The advantage is
Since it can be marked in seconds, it is faster and cheaper than an ink mark that requires several hours for post cure, and has less equipment trouble than an ink mark. In addition, the disadvantages are that the contrast of printing is low and there is a high possibility that a problem of removing soot generated during printing will occur. Therefore, it has been desired to develop a resin composition for semiconductor encapsulation which has high printing contrast and does not generate soot during printing.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an epoxy resin composition for semiconductor encapsulation which has improved YAG laser or carbon dioxide gas laser mark characteristics capable of improving the contrast of printing of a semiconductor package and reducing the generation of soot. To provide.

[0004]

Means for Solving the Problems The present invention has been eagerly studied in order to achieve the above-mentioned object, and by adding a small amount of mica, it is also effective in improving the laser mark characteristics of the epoxy resin composition for semiconductor encapsulation. It was confirmed that the epoxy resin composition for semiconductor encapsulation having the following composition was excellent in solder resistance and moldability.
That is, the present invention is an epoxy resin, a phenol resin curing agent,
A curing accelerator, an inorganic filler, carbon black, and mica having an average particle size of 75 μm or less (K ₂ O / 3Al ₂ O ₃ 6SiO ₂
2H ₂ O) is an epoxy resin composition for semiconductor encapsulation containing essential components.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The components of each composition will be described below. The epoxy resin used in the present invention refers to a compound having an epoxy group in the molecule, and examples of the epoxy resin used include orthocresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin and triphenolmethane type. Examples thereof include epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin and the like. The degree of polymerization and epoxy equivalent of these epoxy resins are not particularly limited. However, in the case of a surface-mountable resin composition for semiconductor encapsulation, it is required to increase the amount of the inorganic filler compounded, and therefore an epoxy resin having a viscosity when melted as low as possible is desired. Further, in order to improve the moisture resistance reliability, it is desirable that chlorine ions, sodium ions and other free ions contained in these epoxy resins are as small as possible.

The phenol resin curing agent used in the present invention refers to a compound containing a phenolic hydroxyl group in the molecule, and examples of the compound used include phenol novolac resin and
Examples thereof include paraxylylene-modified phenol novolac resin, triphenol methane type phenol novolac resin, and bisphenol A type novolac resin. These curing agents may be modified with silicone or the like. Further, the hydroxyl equivalent, the degree of polymerization, etc. are not particularly limited. Similar to the epoxy resin, a curing agent having a relatively low viscosity tends to be desirable for a semiconductor encapsulating resin composition used for surface mounting. Also,
In order to improve the moisture resistance reliability of these resins, it is desirable that chlorine ions, sodium ions, and other free ions contained as impurities are minimized.

The curing accelerator used in the present invention may be any one as long as it promotes a chemical reaction between an epoxy group and a phenolic hydroxyl group, and as an example used, 1,8-diazabicyclo (5,4,0) Undecene-7, 2-methylimidazole, triphenylphosphine, tetraphenylphosphine / tetraphenylborate and the like can be mentioned. In the case of a formulation that combines a low-viscosity epoxy resin and a curing agent, the hardness after molding is low unless the reactivity of the curing accelerator is high,
Since mold release defects occur, it is more desirable to select the type and amount of the curing accelerator capable of sufficiently promoting the curing reaction under the molding conditions.

The inorganic filler used in the present invention includes:
Fused silica powder, spherical silica powder, crystalline silica powder, 2
Examples of the secondary agglomerated silica powder, alumina, and the like are preferable, and spherical silica powder is preferable from the viewpoint of improving the fluidity of the resin composition for semiconductor encapsulation. Regarding the shape of the spherical silica powder, in order to improve the fluidity, it is desirable that the shape of the particles themselves be infinitely spherical and that the particle size distribution be broad. Further, the inorganic filler may be surface-treated in advance with a silane coupling agent described later or other silane-based, titanium-based, or other surface-treating agent. There is no limitation on the amount of the inorganic filler compounded. There is no particular limitation on the average and maximum particle sizes.

The carbon black used in the present invention is
The average particle diameter of the primary particles is 5 to 150 nm. The apparent average particle size may be larger than that due to the secondary aggregation. For laser marks, the important point is how easily carbon black can be removed by laser irradiation. It has been found that the larger the average particle size of carbon black is, the more easily it is oxidized and removed from the surface of the molded article by the heat of the laser. Therefore, it is preferable that the average particle size of the primary particles is 50 to 150 nm. It is not limited. Further, from the viewpoint of moisture resistance reliability, it is more desirable that the content of ionic impurities is small.

The mica used in the present invention is an important technical point in the present invention and has a structure mainly represented by (K ₂ O.3Al ₂ O ₃ .6SiO ₂ .2H ₂ O). belongs to. Mica absorbs laser light when it is irradiated, and emits thermal energy absorbed by the irradiated part. Therefore, when mica is blended and dispersed in the resin composition for semiconductor encapsulation, only the irradiated surface is heated to a high temperature by the laser irradiation, and the epoxy resin and carbon black in that part are rapidly oxidized to be in the air. Will be removed. Since the carbon black is removed, the original white color of the epoxy resin composition appears only on the irradiated surface, and the contrast appears. And Y with short wavelength and strong power
Not only AG laser but also carbon dioxide laser with low power can be printed efficiently.
In the case of a carbon dioxide laser, there is no laser power that can oxidize and remove only carbon black itself, and there was a method of adding an organic dye that develops a color to the carbon dioxide laser in order to provide contrast, Many of these organic dyes are complex, such as the quinone structure,
Moisture resistance reliability tended to be adversely affected. However, the method of blending the mica of the present invention is a method capable of improving the carbon dioxide gas laser mark characteristics without causing a decrease in moisture resistance reliability. In addition, in relation to thermoplastic resins (PE, PP, etc.), a method of adding this mica to improve laser mark characteristics is well known. But,
Until now, it has not been examined by applying this to an epoxy resin, and it has not been confirmed that the laser mark characteristics are improved.

The mica used in the present invention has an average particle size of 75 μ.
m or less. If the average particle size exceeds this range, when compounded in the resin composition for semiconductor encapsulation, it may cause clogging of the gate during molding, and it is not desirable to use it. Further, there is no problem if the surface of the mica is coated with any organic or inorganic compound. Furthermore, there is no problem in using the mica surface by roughening the surface to eliminate the pearly luster of the surface or improving the laser mark property. The amount of mica used is preferably 0.02 to 2% by weight based on 100% by weight of the total resin composition for semiconductor encapsulation. If it is 0.02% by weight or less, the laser mark characteristic is not obtained. If it is 2% by weight or more, the pearly luster is produced, soot is produced at the time of laser marking, and the fluidity is lowered, so that the predetermined performance cannot be exhibited.

In addition to the above, the composition of the present invention may optionally contain a colorant, a brominated epoxy resin, a flame retardant such as antimony trioxide, a silane coupling agent, a silicone oil, and a low stress component such as rubber. It can be added. The epoxy resin composition of the present invention is an epoxy resin, a curing agent,
A curing accelerator, an inorganic filler, and other additives may be mixed at room temperature with a mixer, kneaded with a general kneader such as a roll or an extruder, cooled, and then ground to obtain a molding material.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples. -Example 1 The following composition Biphenyl type epoxy resin (melting point 107 degreeC) 8.3 weight part Phenol aralkyl resin (polymerization degree 3.2) 8.1 weight part 1.8-diazabicyclo (5,4,0) undecene- 7 0.2 parts by weight Spherical silica powder 79.5 parts by weight Carbon black (average particle size 18 nm) 0.3 parts by weight Mica (K ₂ O / 3Al ₂ O ₃ / 6SiO ₂ 2H ₂ O) (average particle size 15 μm) ) 0.5 parts by weight Carnauba wax 0.3 parts by weight Brominated phenol novolac type epoxy resin 1.0 parts by weight Antimony trioxide 1.3 parts by weight Epoxy silane coupling agent 0.5 parts by weight are mixed at room temperature with a mixer. Then, the mixture was kneaded with a biaxial roll at 100 ° C., cooled and pulverized to obtain a resin composition. After molding a semiconductor package using the obtained resin composition, YA
The G laser mark and carbon dioxide gas laser mark characteristics were evaluated, and the results are shown in Table 1.

* Evaluation method << YAG laser mark property >> Using the prepared tablet of the epoxy resin composition for semiconductor encapsulation, a satin molded product is molded. After post-curing at 175 ° C. for 8 hours, the surface was YAG laser marked. Marking was performed under the following conditions, and the contrast, faintness, and soot of the printed characters were visually observed and evaluated as follows. (Conditions) Laser marker: NEC SL476B Laser power: 2.0 kV Pulse width: 150 μsec << Carbon dioxide laser mark property >> Using the prepared epoxy resin composition for encapsulating a semiconductor, a satin molded product is molded. To do. After post-curing at 175 ° C. for 8 hours, carbon dioxide laser marking was performed on the surface. Marking was performed under the following conditions, and the contrast, blur, and soot of the printed characters were visually observed and evaluated as follows. (Conditions) Laser Marker: Lumonix Zymark 7000 Laser Output: 4J

<Evaluation> * Contrast * Variable characters * Soot generation ○: Good None None △: Some defects Somewhat slight Somex: Poor

Examples 2 to 6 Compounds were prepared according to the formulations shown in Table 1, resin compositions were obtained in the same manner as in Example 1, evaluated in the same manner, and the results are shown in Table 1. -Comparative Examples 1 to 5 A resin composition was prepared in the same manner as in Example 1 by blending according to the formulation in Table 2, and evaluated in the same manner. The results are shown in Table 1. In addition, as a particularly problematic matter, the compound of Comparative Example 3 had reduced fluidity and caused molding trouble, and the compound of Comparative Example 4 caused molding trouble such as gate clogging. -The epoxy resin, phenol resin and mica used are as follows. Biphenyl type epoxy resin (melting point 107 ° C) Orthocresol novolac type epoxy resin (polymerization degree 4.2) Phenol aralkyl type resin (polymerization degree 3.2) Phenol novolac type resin (polymerization degree 4.3) Mica (K ₂ O ・3Al ₂ O ₃ · 6SiO ₂ · 2H ₂ O) Mica A (average particle size 15 μm) Mica B (average particle size 50 μm) Mica C (average particle size 85 μm) Mica D (average particle size 15 μm, surface roughening treatment)

Table 1 Example 1 2 3 4 5 6 compounding (parts by weight) Biphenyl type epoxy resin 8.3 8.3 8.3 8.3 8.3 Orthocresol-rnovolak type epoxy resin 10.2 Phenol aralkyl type resin 8.1 8.1 8.1 8.1 8.1 Phenol novolac type resin 6.2 1.8-Jiazavicyclo (5, 4,0) Undecene-7 0.2 0.2 0.2 0.2 0.2 0.2 Spherical silica powder 79.5 79.97 78.2 79.5 79.5 79.5 Carbon black (average particle size 18 nm) 0.3 0.3 0.3 0.3 0.3 0.3 Mica A 0.5 0.03 1.8 0.5 Mica B 0.5 Mica D 0.5 Carnauba wax 0.3 0.3 0.3 0.3 0.3 0.3 Brominated phenolnovolac type epoxy resin 1.0 1.0 1.0 1.0 1.0 1.0 Antimony trioxide 1.3 1.3 1.3 1.3 1.3 1.3 Epoxysilane coupling agent 0.5 0.5 0.5 0.5 0.5 0.5 Characteristics YAG laser mark contrast ○ ○ ○ ○ ○ ○ Character fading ○ ○ ○ ○ ○ ○ Soot generation ○ ○ ○ ○ ○ ○ Carbon dioxide laser mark Contrast ○ ○ ○ ○ ○ ○ Blurred characters ○ ○ ○ ○ ○ ○ Soot generation ○ ○ ○ ○ ○ ○

Table 2 Comparative Example 1 2 3 4 5 Compounding (parts by weight) Biphenyl type epoxy resin 8.3 8.3 8.3 8.3 8.3 Phenol aralkyl type resin 8.1 8.1 8.1 8.1 8.1 1.8-Diazabicyclo (5,4,0) undecene-7 0.2 0.2 0.2 0.2 0.2 Spherical Silica powder 80.0 79.99 77.7 79.5 79.8 Carbon black (average particle size 18 nm) 0.3 0.3 0.3 0.3 Mica A 0.01 2.3 0.5 Mica C 0.5 Carnauba wax 0.3 0.3 0.3 0.3 0.3 Brominated phenol-nornovolac epoxy resin 1.0 1.0 1.0 1.0 1.0 Antimony trioxide 1.3 1.3 1.3 1.3 1.3 Epoxy silane coupling agent 0.5 0.5 0.5 0.5 0.5 Characteristic YAG laser mark property Contrast △ △ ○ ○ × Character blurring ○ ○ ○ ○ × Soot generation △ △ △ ○ × Carbon dioxide laser mark property Contrast × × ○ ○ × Blurred characters × × ○ ○ × Soot generation ○ ○ △ ○ ×

[0019]

Industrial Applicability The epoxy resin composition for semiconductor encapsulation of the present invention produces a semiconductor package having a high YAG laser or carbon dioxide gas laser mark characteristic with high print contrast and low soot production. It is possible to improve the productivity and reduce the production cost at the semiconductor manufacturer.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H01L 23/29 H01L 23/30 R 23/31

Claims (2)

[Claims] An epoxy resin, a phenol resin curing agent,
An epoxy resin composition for semiconductor encapsulation, comprising a curing accelerator, an inorganic filler, carbon black, and mica having an average particle size of 75 μm or less as essential components. 2. A main component of mica is K ₂ O.3Al ₂ O ₃ .6.
The epoxy resin composition for semiconductor encapsulation according to claim 1, which has a structure of SiO ₂ · 2H ₂ O.