JP2801655B2 - Method of manufacturing tray for transporting semiconductor integrated circuit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to injection molding of a polyphenylene ether-based resin, carbon black and a composition containing an ethylene-acrylate copolymer to obtain heat resistance and mechanical properties. The present invention relates to a method for manufacturing a tray for carrying a semiconductor integrated circuit device, which is well balanced in formability and electrical characteristics.

[Conventional technology]

Conventionally, semiconductor integrated circuit device transport trays formed by molding a semiconductive resin made by mixing carbon fiber, carbon black, and metal powder into a thermoplastic resin have been used for semiconductor integrated circuit devices (lead wires are attached to IC chips). It is used as an antistatic plastic tray capable of preventing electrostatic breakdown of the apparatus when loaded and transported (sealed with resin).

Semiconductor integrated circuit devices are often used by mounting a plurality of them on a circuit board made of plastic, ceramic, aluminum, or the like by soldering. However, since the sealing resin is a hygroscopic resin such as an epoxy resin or a phenol resin, the moisture absorbed in the sealing resin is vaporized and expanded when the lead wire of the device is soldered on a circuit board. Troubles that occur when cracks occur in the sealing resin molded article and further impair the function of the IC chip are likely to occur particularly in a surface mount type semiconductor integrated circuit device.

Therefore, recently, a step of drying the apparatus at 120 to 150 ° C. in an oven for several hours to several tens of hours immediately before soldering on a circuit board is increasing.

Conventional antistatic plastic trays are used for loading, storing, and transporting semiconductor integrated circuit devices.
It is not suitable for the drying process of the device. The reason is that the antistatic plastic tray is inexpensive and has good moldability, such as polypropylene and polystyrene. Deformation is remarkable, and there is a defect in that lead wires of a loaded semiconductor integrated circuit device are bent, damaged, and contaminated by molten resin. Therefore, in the drying step of the semiconductor integrated circuit device, a metal tray made of aluminum or the like, which is less thermally deformed, is used.

[Problems to be solved by the invention]

However, metal trays such as aluminum are heavier than plastic trays and, furthermore, have extremely high conductivity, so there is a risk of charge inflow from the outside. Not suitable for use in transport processes. Therefore, in many cases, the semiconductor integrated circuit device is transferred from a plastic tray to a metal tray made of aluminum or the like before the drying step and is dried in an oven. However, once the semiconductor integrated circuit device mounted on the plastic tray is replaced on the metal tray before the drying step, the lead wire of the device is bent or damaged, and the number of processes is increased to increase the manufacturing cost. As a result, there is a growing need for inexpensive plastic trays that can withstand the drying temperatures in the oven.

At present, polycarbonate, polyamide, polyimide,
Antistatic plastic trays based on high heat resistant resins such as polybutylene terephthalate are being developed. These have sufficient heat resistance, but all have a high melting temperature and melt viscosity for molding from a resin in which an inorganic filler such as carbon fiber, carbon black, metal powder, etc. is mixed into a high-temperature molten resin, and the surface of the molded article becomes high. It is easy to cause troubles such as discoloration, flow mark and short shot. In addition, since these resins require high-temperature molding, it is difficult to reinforce with a rubber component, and it is not possible to give a molded article a sufficient impact strength.

On the other hand, there is an example in which an inexpensive general-purpose crystalline resin such as polypropylene is used.

In general, crystalline resins can be improved in crystallinity by mixing inorganic fillers, and can also increase the restraint of crystals and improve heat resistance.However, thermal deformation under load is large, and stacking in ovens Is not suitable for the intended tray specification. Furthermore, such resins contain low-molecular-weight organic acids as crystallization promoters. When semiconductor integrated circuit devices are loaded on trays molded from these resins and heated in an oven, they elute from the trays. Another problem is that the volatile organic acid easily causes troubles when the lead wires of the apparatus are corroded.

The inventors of the present invention have conducted intensive studies and found that, based on polyphenylene ether resin and styrene resin, a resin, carbon black and a composition containing an ethylene-acrylic acid ester copolymer were injection-molded to obtain heat resistance and mechanical properties. A method for manufacturing a tray for transporting semiconductor integrated circuit devices, which is well balanced in formability, electrical characteristics, and price, was developed, and the invention was completed.

[Means for solving the problem]

That is, the present invention relates to (a) 100 parts by weight of a polyphenylene ether-based resin composed of 58 to 96% by weight of a polyphenylene ether polymer and 42 to 4% by weight of a polystyrene polymer, and (b) 10 to 40 parts by weight of a carbon black. And (c) injection molding a resin composition containing 5 to 20 parts by weight of an ethylene-acrylate copolymer to produce a tray for transporting semiconductor integrated circuit devices.

The polyphenylene ether resin used in the present invention means a homopolymer or a blend of a polyphenylene ether polymer and a polystyrene polymer described in US Pat. No. 3,383,435.

The blend composition of 100 parts by weight of the polyphenylene ether-based resin is such that the homopolymer or copolymer of the polyphenylene ether polymer is 58 to 96% by weight, and the polystyrene polymer is 42 to 5% by weight. If the amount of the polyphenylene ether polymer is less than 58% by weight, moldability is improved, but satisfactory heat resistance cannot be obtained when the semiconductor integrated circuit device is used as a tray for processing in an oven.
On the other hand, when the content of the polyphenylene ether polymer exceeds 96% by weight, the heat resistance is improved, but the moldability is reduced and the molding as the tray becomes difficult. Considering the balance between heat resistance and moldability, the content of the polyphenylene ether polymer is preferably 58 to 96% by weight. Further, the content of the polystyrene polymer here is 2 to 7% by weight of rubber in consideration of the balance between the reinforcing effect of impact resistance and the moldability when used as a tray.
The range of the impact-resistant styrene resin or the mixture of the impact-resistant styrene resin containing the same amount of rubber and the transparent styrene resin is optimal.

Next, the carbon black used in the present invention is a granular or powdered conductive carbon black, and examples thereof include a thermal black, an acetylene black and a furnace black. The proportion in the composition is preferably 10 to 40 parts by weight of the carbon black based on 100 parts by weight of the polyphenylene ether-based resin. If the added amount of the carbon black is less than 10 parts by weight, conductivity satisfying the use of the tray cannot be exhibited. On the other hand, if the amount of the carbon black exceeds 40 parts by weight, the fluidity of the resin is remarkably reduced, and it becomes difficult to form the tray. In general, a carbon black having a smaller specific surface area requires a larger amount of addition, but a granular furnace black is preferable in view of the balance between conductivity and moldability and workability. In that case, 100 weight parts of a polyphenylene ether resin is used. It is advisable to add 10 to 40 parts by weight of carbon black to parts by weight.

In the present invention, an ethylene-acrylate copolymer is used in order to improve moldability and impact resistance. Unsaturated rubber is used to reinforce general-purpose resins such as polystyrene and polypropylene resin, but the resin used for the tray of the present invention is processed under high temperature and high pressure. Thermal decomposition cannot be used remarkably.

As the ethylene-acrylate copolymer, the ethylene-ethyl acrylate copolymer has the greatest effect of improving moldability and impact resistance. The addition of an ethylene-ethyl acrylate copolymer to a blend system of a polyphenylene ether polymer and a polystyrene polymer to improve moldability and impact resistance is described in JP-B-53-12539.

In the ethylene-ethyl acrylate copolymer used in the present invention, the content of ethyl acrylate is optimally in the range of 5 to 20% by weight in consideration of the balance between the reinforcing effect and the thermal stability. Further, the amount of the ethylene-acrylate copolymer added was 10 g of polyphenylene ether-based resin.
The optimum amount is 5 to 20 parts by weight with respect to 0 parts by weight. If the amount of the ethylene-acrylate copolymer is less than 5 parts by weight, the effects of improving the moldability and impact resistance of the tray cannot be obtained. If the amount is more than 20 parts by weight, the moldability is improved, but not only the impact resistance is reduced again, but also the heat resistance is remarkably reduced, so that the tray specifications are not satisfied. Therefore, considering the balance of moldability, impact resistance and heat resistance, it is preferable to add 5 to 20 parts by weight of ethylene ethyl acrylate copolymer to 100 parts by weight of polyphenylene ether resin.

Furthermore, in the present invention, various additives such as antioxidants,
Plasticizers, lubricants and flame retardants may be added.

Hereinafter, an implementation method of the present invention will be described. First, the above-mentioned various raw materials are mixed and stirred by a well-known mixer, for example, a Hensiel mixer, a ribbon blender, a tumbler mixer or the like. Next, the mixture is kneaded at 250 to 320 ° C. by a well-known kneader, for example, a co-axial twin-screw extruder, a bi-directional twin-screw extruder, a pressure kneader, or the like.
Pellet shape.

Next, a semiconductor integrated circuit device carrying tray is formed by injection molding from the pelletized semiconductive resin in the manner described above.

The injection molding conditions are, for example, using a hydraulic injection molding machine with a mold clamping pressure of 160 tons, molding temperature 280 to 340 ° C., mold temperature 80 to 14
0 ° C.

The shape of the tray is usually 100-150mm in height, 250-300m in width
m, a thickness of about 5 to 7 mm, and is divided by vertical and horizontal grids, and one semiconductor integrated circuit device is mounted on each grid. The size of one section partitioned by the lattice varies depending on the size of the semiconductor integrated circuit device to be loaded, but in the case of a QFP type IC tray, it is about 10 to 40 mm on each side. Further, a hole for projecting the semiconductor integrated circuit device is opened in the section partitioned by the lattice, and a width of 0.2 to 0.5 is provided between the hole and the lattice so as to surround the hole.
mm, a height of about 0.2 to 1.0 mm micro ribs are formed, the mounted semiconductor integrated circuit device is mounted and fixed by the micro ribs,
Care is taken so that the leads do not touch the tray (FIG. 1). Further, on the back side of the tray, flow assisting ribs may be provided vertically and horizontally to connect the sections partitioned by the grid (FIG. 2).

〔Example〕

 Hereinafter, the present invention will be described based on examples.

Examples 1 to 3 and Comparative Examples 1 to 4 Formulations: Formulations were performed using the compositions shown in Tables 1 and 2.

Mixing: Raw materials powder of the composition shown in Tables 1 and 2, except for the carbon black, was mixed for 2 minutes using a Hensiel mixer. Thereafter, all components including the carbon black were mixed for 3 minutes using a tumbler mixer.

Kneading and pelletizing: The mixed raw material powder was kneaded and pelletized using a co-rotating twin-screw extruder (PCM-45, Ikegai Iron & Steel Co., Ltd.) at a cylinder temperature of 280 ° C. and a cylinder rotation speed of 140 rpm.

Injection molding: A test piece for evaluating physical properties and a QFP type IC tray were molded from the prepared pellets by an injection molding method.

 Table 3 shows examples of molding conditions for the QFP type IC tray.

Table 4 shows the results of the evaluation of general physical properties, and Table 5 shows the results of the heat resistance test.

Surface resistance measuring method Test piece: Plate (120mm × 120mm × 3m) by injection molding
m) created.

Pretreatment: 5mm x 1 silver paint at 9mm intervals on plate
It was applied to a thickness of 0 mm and dried at room temperature to form a silver electrode on the plate.

Measurement: Advanced Digital Multimeter IR-68
At 53, the resistance between the silver electrodes was measured.

 The resistance value was an average value of n = 9 places / sheet.

Heat resistance test method for QFP type IC tray Heat treatment Heated in an oven with 6 trays stacked; 125 ° C, 135
℃, 145 ℃ × 24 hours 6 trays heated and left at room temperature; 23 ℃
× 50% RH × 24 hours Measurement method The following measurement was performed before and after the heat treatment; number of samples n = 6
Sheets / 1 condition ・ External dimensions: vertical and horizontal dimensions were measured with a 1/100 mm precision caliper; 4 sides / 1 sheet warpage was measured with a 1/100 mm precision height gauge; 15
Point / sheet ・ Surface resistance: The surface resistance between two points at 10mm intervals on the front and back of the tray was measured: 12 points / sheet, single side ・ Impact strength: The center of the tray was 6.35mm × 12.7mm Cut out and measured Izod impact strength; 1 piece / 1 piece [Effects of the Invention] As described above, the tray of the present invention injection-molded using the specified resin composition has characteristics balanced in heat resistance, mechanical properties, moldability, electrical properties and price. A semiconductor integrated circuit device carrying tray having the following.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a), (b) and (c) are a plan view and a side view of a tray used for the test of the present invention, and FIG. It is. Reference numeral 1... Lattice 4... Flow assisting rib 2... Hole 5... Flow assisting rib 3.

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Claims (3)

(57) [Claims] 1. A polyphenylene ether polymer (a)
100 parts by weight of a polyphenylene ether-based resin composed of 96% by weight and 42 to 4% by weight of a polystyrene polymer, (b) 10 to 40 parts by weight of a carbon black, and (c) 5 to 20% of an ethylene-acrylate copolymer A method for producing a tray for transporting a semiconductor integrated circuit device, comprising injection molding a resin composition containing parts by weight. 2. The polystyrene polymer contains 2 to 7% by weight of rubber.
The method for producing a tray according to claim 1, wherein the tray is a high-impact styrene resin or a mixture of the high-impact styrene resin and a transparent styrene resin. 3. The carbon black according to claim 1, wherein the carbon black is granular.
The method of manufacturing the tray as described.