JP4623449B2 - Colorant and resin composition for semiconductor encapsulant - Google Patents

Description

  The present invention relates to a colorant composed of a black pigment for a semiconductor encapsulant and a resin composition for a semiconductor encapsulant containing the colorant.

  Semiconductor devices are becoming more and more miniaturized year by year due to market demands for multi-functionality, high integration, and high speed, and advances in design technology and manufacturing technology. Further, multifunctional functions are also required for a sealing material for protecting a complicated device from dust, moisture or external force in the air.

  Generally, semiconductor chips are protected by bonding chips, setting a wire-bonded frame in a mold, injecting thermosetting resin, curing molding, and sealing. An epoxy resin is used, and in addition, a resin composition containing a curing agent, a curing accelerator, an inorganic filler, a colorant and the like as essential components is used.

  The semiconductor resin encapsulant is colored black in order to prevent electrical failure due to photoexcitation current generated when light hits the semiconductor chip. The black colorant has high blackness and excellent light shielding properties. Carbon black is useful.

For example, in Patent Document 1, an epoxy resin, a phenol resin curing agent, a curing accelerator, an inorganic filler, and a carbon black as essential components, the carbon black has an average particle diameter of 10 to 100 nm, according to the BET method. A resin composition for semiconductor encapsulation having a specific surface area of 50 to 500 m ² / g, a pH value of 6.5 to 8.5, and 0.05 to 1.0 wt% of the carbon black in the total resin composition. Has been proposed.

  Patent Document 2 discloses that (A) an epoxy resin, (B) a phenol resin, (C) an inorganic filler, (D) a curing accelerator, (E) 45 μm or more is 500 ppm or less, and its maximum particle size is An epoxy resin composition containing carbon black of 500 μm or less as an essential component, wherein the epoxy resin composition for semiconductor encapsulation contains 0.1 to 1.0% by weight of the carbon black in the total epoxy resin composition. It is disclosed.

Further, Patent Document 3 discloses an epoxy resin composition containing (A) an epoxy resin, (B) a curing agent, (C) an inorganic filler, and (D) carbon black as essential components. An epoxy resin composition for semiconductor encapsulation using carbon black having a particle content of 45 μm or more and a particle content of 30 ppm or less is disclosed.
Japanese Patent Laid-Open No. 08-081544 JP 2000-007894 A JP 2001-019833 A

  Carbon black is effective for preventing static electricity due to its high conductivity, but due to the recent high integration and miniaturization, the space between the inner leads (lead frame) and pads (IC pedestal) and the frame or between the wires (Bonding with gold wire) etc. is becoming narrower, so if carbon black intervenes between the wires, the wires are electrically connected, so there is a leak or short between the wires. Occurs, causing malfunction of the semiconductor device.

  In order to solve this problem, the present inventor conducted intensive research on black pigments instead of carbon black, and as a result, heat treatment was performed in an inert atmosphere of shellac to obtain the above-mentioned problem with the black pigment obtained by polymerizing. And the black pigment was found to be highly dispersed in the epoxy resin.

  That is, the present invention has been completed based on this knowledge, and its purpose is electrical continuity between inner leads (lead frame), between pads (IC pedestal) and frame, or between wires (bonding with gold wire). It is intended to provide a semiconductor encapsulant coloring agent and a semiconductor encapsulant resin composition that are excellent in moldability, reliability, laser-marking property, and the like.

  The colorant for semiconductor encapsulant according to the present invention for achieving the above object is composed of a black pigment obtained by polymerizing and pulverizing shellac at a temperature of 200 to 600 ° C. in an inert atmosphere. It is characterized by.

  Further, the resin composition for a semiconductor sealing material according to the present invention is a black pigment obtained by heat-treating shellac at a temperature of 200 to 600 ° C. in an inert atmosphere at a temperature of 200 to 600 ° C., and an epoxy resin. A structural feature is that a curing agent, a curing accelerator, and an inorganic filler are essential components.

  The colorant for semiconductor encapsulating material of the present invention comprising a black pigment obtained by heat-treating shellac in an inert atmosphere at a temperature of 200 to 600 ° C. to be polymerized and pulverized has high blackness, low conductivity, and epoxy. Excellent resin dispersibility in resin, etc. According to the resin composition for a semiconductor encapsulant containing this colorant as an essential component, it has excellent light shielding properties, and further, between inner leads, between pads and frames, between wires, etc. It is possible to suppress the occurrence of electrical failure due to electrical conduction.

  Shellac is a refined resin-like secreted material covering the body of the silkworm, Laccifer Lacca Kerr, whose body length is 0.6 to 0.7 mm. It has the only thermosetting property among natural resins. It is resin which has. The growth condition of the larvae is limited to a part of the subtropics, and India and Thailand are the two major production areas. In Japan, it is manufactured by Nippon Shellac Industrial Co., Ltd. and Gifu Shellac Manufacturing Co., Ltd. The estimated structural formula of shellac is said to be expressed by the chemical formula (1).

  The main component of shellac is a mixed lactide of 2 moles of allelic acid, 2 moles of seronic acid, and 4 moles of shellac resin acid. It is a light tan or brown flake-like strip that is hard, brittle, shiny and has an odor. There is no or slightly unique odor. Although it is insoluble in water, ether, hexane, and isooctane, it is soluble in ethanol and propylene glycol. For example, propylene glycol has a solubility of 100 mg / ml at 25 ° C. and 500 mg / ml at 37 ° C.

  In the present invention, the shellac is polymerized by heat-treating this shellac at a temperature of 200 to 600 ° C. in an inert atmosphere, and the pulverized black pigment is used as a colorant for a semiconductor sealing material. When the heat treatment temperature is low and less than 200 ° C., components contained in shellac may be eluted in the temperature range when the semiconductor is sealed. On the other hand, when the heat treatment temperature is high and the temperature exceeds 600 ° C., the electric resistance is low. Therefore, electrical continuity is likely to occur between the inner leads, between the pad and the frame, between the wires, and the like.

  The heat-treated shellac is pulverized by a pulverizer such as a jet mill, a cutter mixer, or a ball mill, and further classified as necessary to obtain a black pigment.

  The resin composition for a semiconductor sealing material of the present invention is obtained by mixing this shellac with heat treatment in an inert atmosphere and pulverizing the black pigment, an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler as essential components. Thus, a resin composition is obtained.

  There is no restriction | limiting in particular as an epoxy resin, The epoxy resin generally used for sealing can be used. For example, an epoxy resin obtained by epoxidizing a novolac resin synthesized from phenols and aldehydes such as a phenol novolac type epoxy resin, an orthocresol novolak type epoxy resin, a bisphenol A type epoxy resin, and an alkyl-substituted or unsubstituted biphenol type Epoxy resin, alkyl-substituted or unsubstituted glycidyl ether-type epoxy resin, glycidylamine-type epoxy resin obtained by reaction of polyamine such as isocyanuric acid and epichlorohydrin, biphenyl-type epoxy resin, dicyclopentadiene and phenols and / or naphthols Epoxy products of co-condensation resins, epoxy resins having a naphthalene ring, phenol / aralkyl resins, aralkyl-type phenol resins such as naphthol / aralkyl resins Products, trimethylolpropane type epoxy resins, linear aliphatic epoxy resins obtained by oxidizing olefinic bonds with peracids such as peracetic acid, alicyclic epoxy resins, and the like. The above may be combined. In addition, in order to ensure the reliability of a device for these resins, the chlorine contained in the resin is desirably 1500 ppm or less.

  The curing agent is not particularly limited, and generally used phenols such as phenol, cresol, resorcin, catechol, bisphenol A, and bisphenol F and / or naphthols such as α-naphthol, β naphthol, and disidroxynaphthalene and formaldehyde Examples include resins obtained by condensation or cocondensation of aldehydes and the like with an acidic catalyst, aralkyl-type phenol resins such as phenol / aralkyl resins, naphthol / aralkyl resins, etc., alone or in combination of two or more. It can also be used.

  The curing accelerator is not particularly limited as long as it is a compound having a catalytic function for promoting the reaction between the epoxy resin and the curing agent. For example, 1,8-diazabicyclo (5,4,0) undecene-7, 1,5-diazabicyclo (4,4,0) nonene, 5,6-dibutylamino-1,8-diazabicyclo (5,4,0 ) Tertiary amines such as benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol and their derivatives, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, etc. Imidazoles and their derivatives, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine and phenylphosphine, and these phosphines have π bonds such as maleic anhydride, benzoquinone and diazophenylmethane Phosphorus compounds having intramolecular polarization formed by adding compounds, Laphenylphosphonium, tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, N-methyltetraphenylphosphonium-tetraphenylborate, triphenylphosphonium-triphenylborane, etc. These may be used alone or in combination of two or more.

  Inorganic fillers used to reduce hygroscopicity and improve strength include fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, boron nitride, beryllia, zirconia, etc. There are single crystal fibers such as beads, potassium titanate, silicon carbide, silicon nitride, and alumina, glass fibers, etc., and one or more of these can be blended. Furthermore, aluminum hydroxide, zinc borate, or the like can be used as an inorganic filler having a flame retardant effect.

  In addition to the above essential components, the resin composition for a semiconductor encapsulant of the present invention includes a flexible agent such as silicone rubber, various coupling agents, and a release agent such as carnauba wax and polyethylene wax as necessary. In addition, additives such as a surface treatment agent, a flame retardant, and a flame retardant aid may be appropriately blended.

  The resin composition for a semiconductor encapsulant of the present invention is a black pigment obtained by polymerizing and pulverizing shellac in an inert atmosphere at a temperature of 200 to 600 ° C., the above epoxy resin, a curing agent, and curing acceleration. After mixing thoroughly with a pulverizer, three rolls, ball mill, planetary mixer, etc. at a predetermined ratio together with the agent, inorganic filler, etc., it was melt-mixed with a hot roll or kneader, and then cooled and solidified. Thereafter, it is pulverized to an appropriate size.

  Hereinafter, although the Example of this invention is described, this invention is not restrict | limited to this Example.

Example 1
1000 g of shellac (manufactured by Gifu Shellac Manufacturing Co., Ltd., shellac GSN) was polymerized by heat treatment at 400 ° C. for 1 hour in a nitrogen atmosphere, and the resulting black phosphorus flakes were converted into a single-track jet mill (manufactured by Seishin Enterprise Co., Ltd., Colorant 1 was produced by grinding with STJ-200).

Comparative Example 1
Colorant 2 was produced in the same manner as in Example 1 except that the heat treatment temperature was changed to 180 ° C.

Comparative Example 2
Colorant 3 was produced in the same manner as in Example 1 except that the heat treatment temperature was changed to 600 ° C.

Comparative Example 3
Titanium powder (Ti) and titanium oxide (TiO ₂ ) were mixed and heat-treated in a vacuum at a temperature of 1600 ° C. until the blackness became constant, whereby a titanium oxide black powder was produced as the colorant 4. From the results of X-ray analysis, it was confirmed that the colorant 4 was mainly composed of TiO and Ti ₂ O ₃ .

Comparative Example 4
A phthalocyanine dye (YKR-3080, manufactured by Yamamoto Kasei Co., Ltd.) was used as colorant 5 as it was.

  These colorants 1 to 5 are mixed in the proportions (parts by weight) shown in Table 1, mixed for 10 minutes with a biaxial roll (roll surface temperature 80 ° C.), then cooled and pulverized for use in a semiconductor encapsulant. A resin composition was prepared.

Using these resin compositions, molding was performed with a transfer molding machine under conditions of a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm ² , and a curing time of 90 seconds, followed by post-curing at 175 ° C. for 6 hours, and sealing. A stop material was produced. About the obtained sealing material, the measurement test was done by the following method.

Spiral flow;
A mold according to EMM11-66 was set in a transfer molding machine, the resin composition was molded under the above conditions, and the flow distance (cm) was determined.

Volume resistivity;
A circular mold was set in a transfer molding machine, and the resin composition was molded into a disc having a diameter of 100 mm and a thickness of 3 mm under the above conditions, and after curing, a voltage of 500 V and a temperature of 150 ° C. were used using a volume resistance meter. Insulation was confirmed by measuring the resistance.

Moisture resistance;
SOP (Small Outline Package) -28 pin is used as a resin-encapsulated semiconductor device (external dimension, 18 × 8.4 × 2.6 mm), and 9.6 × 5.1 mm with 42 alloy material (processed dimple) on the lead frame. Transfer molding and post-curing under the above conditions. Next, after absorbing moisture at 85 ° C./85 RH% for 72 hours, after pre-treatment at 240 ° C./10 seconds, it was left in PCT (121 ° C./2 atm) to determine whether the wiring on the chip was disconnected. .

Solder heat resistance;
QFP-80 pins are used as a resin-encapsulated semiconductor device (external dimensions, 20 × 14 × 2.0 mm), and a chip with a chip size of 8 × 10 mm made of 42 alloy material (no processing) is used for the lead frame. And post-cured. Next, after absorbing moisture for a predetermined time under the condition of 85 ° C./85 RH%, the occurrence of cracks was observed when the treatment at 240 ° C./10 seconds was performed, and the appearance crack occurrence rate was measured.

Laser mark property;
The surface of the package was printed with a YAG laser marking device using a QFP-54 pin resin-encapsulated semiconductor device, and the mark property was visually evaluated. The marking conditions for the YAG laser are as follows.
YAG laser wavelength; 1064 nm
Laser power: 5J
Pulse width: 50 μsec

Electrical properties;
LQFP (Lowprofile Quad Flat Package) A 176-pin resin-encapsulated semiconductor device was used to evaluate the presence or absence of leakage current.

Blackness;
The disc mold was set on a transfer molding machine, and the resin composition was molded into a disc having a diameter of 100 mm and a thickness of 2 mm under the above conditions, and after post-curing, it was measured with a color difference meter. It shows that blackness is so high that this value is small.

  The obtained results are shown in Table 2.

  Comparing the example with the comparative example, it can be seen that the example has a long spiral flow and excellent moldability, high volume resistivity, excellent electrical characteristics, laser markability and blackness. .

Claims (2)

  A colorant for a semiconductor encapsulant comprising a black pigment obtained by heat-treating shellac in an inert atmosphere at a temperature of 200 to 600 ° C. to polymerize and pulverize.   A black pigment obtained by heat-treating shellac in an inert atmosphere at a temperature of 200 to 600 ° C. to be polymerized and pulverized, an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler are essential components. The resin composition for semiconductor sealing materials characterized by the above-mentioned.