JPS6185829A - Transfer resin molding process of semiconductor element - Google Patents

Abstract

PURPOSE:To prevent any residual air from mixing with molten resin material without fail by a method wherein both of feed channel and cavity are vacuumized simultaneously with pressure-feeding process of molten resin material. CONSTITUTION:A lead frame fitted with a semiconductor element is set to the specified position of cavity 6...6 for molding process. Firstly a pot 4 is filled with resin material 3 to be heated up to specified temperature by a heater further pressurized by a plunger 5 for melting the material 3. Secondly the plunger 5 is further lowered to pressure-feed the molten resin material 31 to the cavity 6...6 side. Simultaneously with the pressure feeding process, any residual air in feed channel 7 and cavity 6...6 is forcibly sucked and externally exhausted respectively through a suction channel 8 and an air vent 10 to vacuumize the channel 7 and cavity 6...6 so that the molten resin material 31 may be pressure-fed to the cavity 6...6 through the feed channel 7 with stoppers 91, 111 closed up.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an improvement in a resin molding method for a semiconductor element mounted on a lead frame. It is used in the field of molding technology industry where resin molding is performed using metal molds.

(Prior Art) A basic configuration example of a transfer mold mold for a semiconductor device includes, for example, a fixed upper mold, a rotation/lower mold disposed opposite to the fixed upper mold, a resin material supply pot, and the pot. a heater and a plunger for melting the resin material inside;
The molding cavity portion provided oppositely between the molds, and the inside of the cavity and the bot are connected to each other by i! l! It is known to have a transfer path for molten resin material consisting of a cull section for oil, a runner section, and a gate section. When performing resin molding of a conductive element using such a conventional mold, the semiconductor element on the lead frame is set in a predetermined position in the cavity, both molds are clamped, and then, A resin material is supplied into the pot and heated and pressurized to melt it, and then the molten resin material is injected under pressure into the cavity through a transfer path, thereby molding a semiconductor element with the resin.

By the way, air remains in the pot, transfer path, and cavity of the mold after the mold line, and if this residual air gets mixed into the molten resin material in the cavity, the molded resin body will be damaged. Items that form voids (bubbles), pinholes, or missing parts on the internal or external surface, which cause adverse effects such as lowering the water resistance (moisture) and reliability of semiconductor molded products and impairing their appearance. However, in the conventional method for discharging the residual air, the flow of the molten resin material transferred under pressure to the cavity side is fully used, so the pressurizing force of the resin material by the planter is In addition to increasing the amount of resin material more than necessary or using more resin material than necessary, residual air in the transfer path may become entangled in the resin material when the molten resin material is transferred under pressure. There is a problem that it is not possible to reliably prevent this from being injected into the cavity, which reduces the overall durability of the mold, reduces the effective utilization rate of the resin material, and furthermore However, this method has drawbacks such as inability to reliably mold high-quality semiconductor molded products.

(Problems to be Solved by the Invention) The present invention efficiently exhausts the air remaining in the transfer path of the molten four-fingered material and the cavity in the transfer mold mold to the outside, so that the remaining air is removed from the molten resin. The object of this invention is to reliably prevent the residual air from being mixed into the material, thereby solving the above-mentioned conventional problems caused by the mixing of the residual air.

Further, the present invention aims to improve the effective utilization rate of the resin material used and the overall durability of the mold used.

(Means for Solving the Problems) A transfer resin molding method for a semiconductor element according to the present invention involves setting a lead frame on which a semiconductor element is mounted in a cavity of a nine-car type, which are arranged facing each other. Perform the warping process of the transfer mold mold for mold matching, then perform the resin material supply process into the mold bot,
Next, a resin material melting process is performed in which the resin material in the pot is heated and pressurized to melt it, and then the melted resin material in the pot is transferred to the cull part and runner part of the mold.・A pressurized transfer process is carried out to inject the molten resin material into the molding cavity through the transfer path consisting of the gate section, and at the same time, the residual air in the transfer path is removed from the runner section in the transfer path. A vacuum process is performed in the transfer path to suck and remove the air to the outside, and a vacuum process is performed in the cavity to suck and remove the remaining air in the cavity to the outside from an air vent communicated with the cavity, and then,
The present invention is characterized in that a mold opening step is performed in which the terminal end of the transfer path is closed to open the molten resin material transfer path, and both molds are opened to take out the semiconductor resin molded product to the outside. .

(Function) Therefore, in the method of the present invention, since the air remaining in the transfer path and the cavity is efficiently and reliably removed, in addition to the cavity condition 1, the molten resin material being transferred is This prevents the above-mentioned Q accumulated air from being mixed in.

In addition, due to the 8 closing process on the route end side of the transfer route,
Since the flow of the molten resin material to the outside is prevented, the pressurized injection of the bath @resin material into the cavity through the gate part of the path is performed under equal conditions. It is what it is.

(Example) Next, the method of the present invention will be explained based on examples.

FIGS. 1 and 2 show the main parts of a transfer mold mold used when using the method of the present invention,
The mold consists of a fixed upper mold 1, a movable lower mold 2 arranged opposite to the upper mold 1, a nozzle 4 for supplying resin material 3 arranged on the upper mold 1 side, and a mold fitted into the bot 4. The grunger 5 for pressurizing the combined resin material, the molding cavities 6...6 provided oppositely between the upper and lower molds 1 and 2, and the parting line P- of the lower mold 2.
A cull portion 71 that communicates the cavities 6...6 disposed on the L surface with the bot 4, a runner portion 7□, and a gate portion 7. a transfer path 7 for the molten resin material, a heater for heating the resin material in the bot 4, a cavity 6...6, an ejector mechanism (not shown) for the resin molded body molded in the transfer path 7, etc. It is configured.

Further, a vacuum source (
Intake (for Bakeem) route 8 connected to the (not shown) side
is opened for communication, and the end portion 7 of the intake path is located closer to the bot 4 than the communication opening 8 of the intake path. (Runner section 7)
is provided with a nutonba uniform structure 9 that communicates or closes the intake passage communication opening 81 slowly.
and the stopper at the end of the path 7. (a hydraulic (pneumatic) device 92 that moves the engine forward and backward relative to the engine).

Furthermore, as shown in FIG. 2, an air vent (intake path) lo connecting the cavity 6 and a vacuum source (not shown) is opened in the cavity 6... air vent) 10 communication opening 10. Also, at a position on the vacuum source side, there is provided a nutoper mechanism 11 for communicating or closing the cavity 6 and the vacuum source side. and a hydraulic (pneumatic) device (not shown) that moves the stopper forward and backward with respect to the air vent 10.

Note that the reference numerals in the drawings indicate sealing members disposed on the parting line P-L of both dies 1 and 2.

When performing resin molding of a semiconductor element using the above-mentioned mold, first, a lead frame with a semiconductor element attached thereto is set in a predetermined position in the cavity 6...6, and the mold is clamped. A resin material 3 is supplied into the bot 4, and then the material 3 is heated to a required temperature with a heater and melted by applying pressure with a plunger 5 as shown in FIG. , 1 langeer 5 is further lowered and molten resin material 3□ is poured into cavity 6...6g! Transfer to I under pressure. In addition, at the same time as pressurized transfer of the material 31,
, activate the vacuum source to remove the transfer path 7 and the cavity 6...
- The remaining air in the transfer path 7 and the cavities 6 . . . 6 are forcibly sucked and removed to the outside through the intake path 8 and the air vent 10, respectively, to create a vacuum state in the transfer path 7 and the cavities 6...6.

Next, the stopper uniform Li4 hydraulic (pneumatic) device aff (9
g) Ti move, its stopper 9.・t l, the above-mentioned intake path 8 and air vent) 10's continuous opening 81
・10□ is closed off from the bot 4 side and the cavity 6 side, and in this state, as shown in FIG. ... 6 under pressure, and after the required time has elapsed, stoppers 9+ and 11. All that is required is to move the mold back to the original position, open the mold, and take out the semiconductor resin molded product and the cold puffer fish molded in the transfer path 7 and the like between the molds 1 and 2 using the ejector mechanism.

Note that the downward movement of the plunger 5 described above temporarily stops the downward movement when the molten resin material 3I is filled into the force p part 71 (the state shown in FIG. 3), and the transfer path 7 and the cavity are The above-described pachyme steps in steps 6...6 may be performed more reliably. Further, the vacuum step is continued until the plunger 5 is completely lowered (the fourth step).
Figure) It is preferable to continue.

In the embodiment described above, the transfer path 7 and the cavity 6
... Since the inside of the cavity 6 can be maintained in a vacuum state, it is possible to efficiently and reliably prevent residual air from entering the molten resin material, and the molding inside the cavity 6 ... 6 can be carried out. It is possible to reliably prevent the formation of voids, pinholes, or defects caused by the above-mentioned Gf4 air on the inner or outer surface of the semiconductor resin molded body.

In addition to the above-mentioned actions and effects, m-fusion resin material 3□
To achieve uniformity and high quality of the resin molded product by equalizing the pressurized injection conditions of 3° of the material injected into the cavities 6...6 through the gate 7 and through the gate 7 by preventing the material from flowing out to the outside. At the same time, it is possible to reduce the amount of resin material used and improve the effective utilization rate.
(3,) The pressing force of the plunger 5 against Ic can be maintained constant, and the durability of the molding die can be improved.

(Effects of the Invention) According to the method of the present invention, residual air in the mold is not mixed into the ml1Ata fat material transferred under pressure, so that no voids or pinholes are formed inside or on the outer surface of the semiconductor resin molded product. Otherwise, no defects are formed, and therefore, the water resistance (humidity) and reliability of semiconductor molded products can be significantly improved, and semiconductor molded products with excellent appearance can be molded. It is something to play. In addition, it is possible to equalize the pressurized injection conditions of the molten resin material into the cavity, to improve the quality of semiconductor molded products and to improve the effective utilization rate of the resin material by applying pressure to the material, and to improve the effective utilization rate of the resin material. Since the durability of the mold can be improved, the above-mentioned problems of the conventional method can be reliably solved, which is an excellent effect.

[Brief explanation of drawings]

The figures show an embodiment of the method of the present invention, in which Fig. 1 is a partially cutaway longitudinal cross-sectional view showing the main parts of a transfer mold mold for a semiconductor element, and Fig. 2 is a partially cutaway plan view of the cavity part thereof. , FIG. 3, and FIG. 4 are all explanatory diagrams of the operation of the uninvented method. 1... Upper mold, 2-... Lower mold, 3... Resin material,
31... Molten resin material, 4... Pot, 5
... Plunger, 6... Cavity, 7...
・Transfer route, 7I...Cull part, 7□...Runner part, 7□-...Gate part, 74-...Route end part, 8...Intake route, 9...Stock tube 94 structures, 10-... air vent, 11... Nutnover mechanism. Patent Applicant Long 1) Michio [-] Representative Patent Attorney Iwaki Kata -2''・, -Tori Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A lead frame with a semiconductor element attached is set in the cavities of both molds arranged facing each other, and a mold clamping process of the transfer mold mold is performed to match the two molds. Next, resin is poured into the mold pot. A material supply process is performed, and then a resin material melting process is performed in which the resin material in the pot is melted by heating and pressure. A pressurized transfer process is carried out to inject the molten resin material under pressure into the molding cavity through a transfer path consisting of a runner section and a gate section. A vacuum process is performed in the transfer path to suck and remove air to the outside, and a vacuum process is performed in the cavity to suck and remove residual air in the cavity to the outside from an air vent communicated with the cavity, and then the transfer path is vacuumed. The transfer path is closed by closing the end of the path to prevent the molten resin material from flowing out. Furthermore, after the required resin molding time has elapsed, the transfer path is opened and both molds are opened to form the semiconductor. A transfer resin molding method for a semiconductor element, characterized by performing a mold opening process to take out a resin molded product to the outside.