JPS62176136A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make appearance excellent and to eliminate voids, by controlling a speed of a resin, which flows through a part that is bonded with metallic wires, and pressure keeping force before the resin is completely filled within specified ranges. CONSTITUTION:It is desirable that packaging conditions of a semiconductor element chip using polyphenylene sulfide are as follows: temperature of resin injected in a metal mold is 310-360 deg.C; temperature of the metal mold is in the range of 130-200 deg.C; and the speed of fused resin, which flows through a part bonded with metallic wire is 3-60mm/sec. After the fused resin has passed through the wire bonded part, it is necessary to specify the flowing speed of the fused resin by pressure keeping force. Change to the pressure- keeping-force specifying process must be performed at a time point when the internal pressure in a cavity does not exceed 100kg/cm<2>. The pressure keeping force should be determined so that the internal pressure in the cavity is kept in the range of 10-100kg/cm<2>.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention manufactures a semiconductor device by injection molding a semiconductor element chip 7° wire-bonded to a metal lead with a polyphenylene sulfide resin composition. It is about the method.

(Prior Art and Problems to be Solved by the Invention) Electronic components, especially semiconductor chips that are encapsulated with a synthetic resin by attaching metal wires to metal leads, are widely practiced using epoxy resin or the like. Since it is a thermosetting resin, it has drawbacks in terms of productivity such as a long molding cycle, easy formation of flakes, and poor yield.In recent years, sealing using polyphenylene sulfide resin, a thermoplastic resin, has been attracting attention. .

In order to seal a semiconductor chip with the polyphenylene sulfide resin, it is necessary to lower the melt viscosity during molding of the resin. Even if the polyphenylene sulfide resin is injected into the mold with injection pressure, the appearance of the resin-sealed semiconductor device is likely to be poor, and voids are also likely to occur inside. On the other hand, it has been found that increasing the injection pressure in an attempt to improve the appearance places a large stress on the bonding wire, leading to large deformation or breakage in some cases. This is because when polyphenylene sulfide resin is injected into a mold, the mold temperature is extremely low compared to the resin temperature, so while the resin passes through the mold, the melt viscosity increases and it tends to solidify. This is a major difference from epoxy resins, which have almost no such phenomenon.

Therefore, it is extremely difficult to control the resin injection pressure of the injection molding machine, that is, the injection pressure, and the reproducibility is lacking.

(Means for Solving the Problems) In view of the above situation, the present inventors have made it possible to obtain a resin-sealed semiconductor device with good appearance and no voids without applying a large stress to the sanded wire. Moreover, as a result of studying the manufacturing method of semiconductor devices sealed with polyphenylene sulfide resin, which can be easily obtained with good reproducibility, it was found that the speed at which the resin flows through the bonded portion with the metal wire is within the range of 3 to 60 m/ssc. control.

Furthermore, we have discovered that the above problem can be solved by controlling the pressure inside the cavity within the range of 10 to 100 k < 97 cm' using a holding force before the resin is completely filled, leading to the present invention. It is something.

Copolymer resins can also be used as the polyphenylene sulfide resin of the present invention without departing from the general scope. or,
The composition comprising the polyphenylene sulfide resin is AS
Melt flow rate measured at TM D1238-74 (316℃, 5 o'clock load) is 3000 to 100OOF
/ 100 parts by weight of polyphenylene sulfide resin and 100 to 300 parts by weight of an inorganic filler,
Preferred inorganic fillers are silica, diatomaceous earth, alumina,
Titanium oxide, zinc oxide, antimony oxide, pumice, calcium carbonate, magnesium carbonate, potassium titanate, calcium sulfate, barium sulfate, talc, clay, mica,
Examples include granular or fibrous fixed or amorphous materials such as asbestos, glass, calcium silicate, montmorillonite, bentonite, wollastonite, silicon carbide, and mixtures thereof. In particular, in the present invention, in order to reduce the stress on the bonding wire,
Inorganic fillers having the following sizes are preferred.

Particularly preferable among the inorganic fillers are spherical fillers, and the proportion of the spherical fillers in the inorganic fillers 't-50
By setting the amount to be at least % by weight, deformation and stress of the bonding wire can be reduced. Particularly preferred spherical fillers are glass beads, silica beads, and ceramic beads.

Furthermore, known additives such as coupling agents, antioxidants, heat stabilizers, corrosion inhibitors, lubricants, colorants, etc. can be added to the polyphenylene sulfide resin composition used in the present invention.

The melt viscosity of the polyphenylene sulfide resin composition of the present invention comprising the above components is 10 at 330 to 360°C.
0 to 1000 poise, if it is less than 100 poise, the molecular weight of the polyphenylene sulfide resin used will have to be lowered, resulting in a decrease in the mechanical strength of the sealing molded product, while if it exceeds 1000 poise, it will be difficult to bond the wire. This is not desirable as it increases stress.

The semiconductor device chip sealing conditions using the polyphenylene sulfide resin composition of the present invention are mold injection resin temperature of 310 to 3
It is preferable that the flow speed of the molten resin in the part gendered by the metal wire is 3 to 60 m/aec at a temperature of 60°C and a mold temperature of 130 to 200°C.
If the speed is less than 3 ram/age, the molten resin is likely to solidify and the appearance of the encapsulated molded product will be poor;
/sea is undesirable because the stress on the bonding wire becomes large and causes deformation, damage, etc.
The metal wire used here is made of various metals such as gold and aluminum and has a diameter of 10 to 250 μm.

In order to control the flow rate of the molten resin in the area bonded by the metal wire to within the range of 3d60w/see, it is necessary to adjust the screw position in the cylinder of the sealing machine when the molten resin flows through the area. Although it is possible to set a predetermined injection pressure to achieve the above-mentioned speed at that point.

The injection pressure must be changed over time because injection resistance gradually occurs as the resin is injected into the mold, and it is practically extremely difficult to control. Therefore, according to the present invention, by controlling the screw moving speed at the corresponding screw position, that is, the injection speed, the flow speed of the molten resin in the wire bonded part is adjusted to 3-60°.
It is necessary to set rrrm/see.

In the present invention, after the molten resin flows through the wire bonding part, it is due to the holding force! It is necessary to specify the flow rate of the molten resin.If the injection speed is specified until it reaches complete filling, it is undesirable because it will generate an unnecessarily large pressure in the cavity, and it is not desirable to specify the flow rate of the molten resin until it reaches complete filling. It is important to set the cavity internal pressure to a predetermined low pressure by using a predetermined process using holding pressure. It is preferable to switch from the injection speed regulation step to the holding pressure regulation step at the screen ↓τ forward position of the injection molding machine or at the pressure value generated during the injection speed regulation step.

Switching to the holding pressure specified process is performed when the cavity internal pressure is 10
It must be carried out when the internal pressure of the cavity does not exceed 0 kg/7cmz, and the holding pressure is 10 to 100 kg/-
It should be determined to be kept within the range of +++2. If the internal pressure of the cavity is less than 10 kg 7 cm, it is likely to cause gate formation and damage the adhesion between the resin and the semiconductor element. On the other hand, if it exceeds 100 kg 7 cm, unnecessary stress may be applied to the bonding wire. is undesirable because it causes a decrease in the reliability of the semiconductor device.A particularly preferable range of the cavity internal pressure is 15 to 75
kg7cm2.

The injection molding machine preferably has specifications that allow precise regulation of the injection speed, and the most preferred is an injection molding machine that maintains the specified injection speed through feedback control. By employing this manufacturing method, it is possible to produce resin-sealed semiconductor devices with good appearance, no stress on bonding wires, and with good reproducibility.

(Example) The present invention will be explained below with reference to Examples and Comparative Examples.

Example 1 A polyphenylene sulfide resin composition obtained from 35 parts by weight of polyphenylene sulfide resin (melt viscosity 500 at 330°C), 50 parts by weight of silica beads, and 15 parts by weight of glass fibers with an average fiber length of 50 μm. (0,18c) as shown in Figure 1.
A resin-sealed semiconductor device was prepared in which a 16-pin metal lead (m'') and a semiconductor element were bonded with a metal wire (all sides with a diameter of 25 μm).

The molding machine used was a 1 ounce capacity injection bottom type machine (closed loop feedback control specification) and an 8 capacity mold sound. Resin temperature is 345℃, mold temperature is 16℃
The injection speed at the screw position corresponding to the flow of the entire resin in the wire gonding section at 0° C. was set (injection pressure was not controlled).The speed at which the resin flows was controlled as shown in Table 1. Note that the switching to the specified process using holding pressure was performed after the wire passed through the sanding section and when the generated cavity internal pressure reached 35 kg 7 cm'', and then the holding force of the molding machine was set to 75 to 9/art''.

The cavity internal pressure remained at 3 s kg/cIn" even after pressure retention. Table 1 *1: Shown in terms of wire inclination angle.

In the case of 0 degrees, there is no deformation.

Comparative Example 1 Molding was carried out in the same manner as in Example (the injection pressure at the screw position corresponding to when the resin flows through the wire bonding part was set as shown in Table 2, and the injection speed was not controlled).

1 in Table 2: Indicated by inclination angle (degrees) When controlled by injection pressure as shown in Table 2, both the appearance of the molded product against soil and the deformation of the binding wire compared to the example. It can be seen that the range of conditions in which the condition is favorable is extremely small.

Comparative Example 2 Cavity internal pressure t-35 in case 3 in Table 1 of Example 1
kg/c! When the holding force was set to a maximum of 5 kg 7 cm (97 cm2 for 45), gates were observed in the molded product.On the other hand, when the cavity internal pressure reached 130 9/
Specify the holding force to be 250kg/1wr
”) As a result, the binding wire was cut.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a resin-molded semiconductor device in which a metal lead and a semiconductor element chip are bonded with a metal wire.

Claims (1)

[Claims] 1. A semiconductor chip is fixed on a supporting metal substrate, the electrodes of the semiconductor element and metal leads are bonded with metal wires, and further sealed from the outside by injection molding with a polyphenylene sulfide resin composition. When manufacturing a semiconductor device that is stopped, the injection resin temperature is set at 310 to 360°C.
The mold temperature is 130 to 200°C, and the speed of the resin composition flowing through the wire bonding part is 3 to 60 mm/
The injection speed is set so that the injection speed is 10 to 10 seconds, and then the cavity internal pressure is set to 10 to 10
A method for manufacturing a semiconductor device, characterized in that an injection process is terminated by defining a holding force within a range of 0 kg/cm^2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the polyphenylene sulfide resin composition has a melt viscosity of 100 to 1000 poise at 310 to 360°C. 3. Polyphenylene sulfide resin composition is 50% by weight
3. The method of manufacturing a semiconductor device according to claim 1, wherein the inorganic filler contains the above inorganic filler, and 50% by weight or more of the inorganic filler has a maximum length of 100 μm or less. 4. The method for manufacturing a semiconductor device according to claims 1 to 3, wherein 50% by weight or more of the inorganic filler contained in the polyphenylene sulfide resin composition is a spherical filler. 5. The method of manufacturing a semiconductor device according to claims 1 to 4, wherein the injection speed and holding force are defined by feedback control. 6. Manufacture of a semiconductor device according to claims 1 to 5, wherein the switching from the process defined by injection speed to the process defined by holding pressure is performed by the pressure level within the cavity generated during the process defined by injection speed. Law.