JPS63126714A - Mold press device - Google Patents

Abstract

PURPOSE:To shorten the mold press process time and carry out package molding of high reliability by providing a heating means and cooling means inside a mold, and controlling its working. CONSTITUTION:In a injection process, the temperature of a mold 8 is sensed by a temperature sensor 18, and by operating a heater 12, a subheater 12a or a cooling tube 14 properly by a temperature control section 17, the mold 8 is controlled in such a manner as to be at a fixed temperature lower than curing temperature of the resin. By said arrangement, the resin is applied uniformly all over a cavity 13, therefore voids and the like will hardly occur. In the curing process, the temperature of the mold 8 is set higher than that of the curing temperature of the resin. By said arrangement, rapid heating is effected. When the curing process is completed, a temperature control section 17 cools down the mold 8 rapidly close to the normal temperature. Then, by opening a top force 8a and a bottom force 8b, a molded package is removed out. The molded package is in a state of heat shrinkage, so it can be removed out of the mold 8 easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique that is effective when applied to a mold press apparatus, particularly a mold press apparatus used for forming a package of a semiconductor device.

[Conventional technology]

The mold press apparatus is described in, for example, the Stock % Type % Apparatus Guidebook JP175 to P179.

Here, an overview of various packaging devices is introduced.

The present inventor studied a mold press apparatus which is a packaging apparatus for manufacturing resin mold type semiconductor devices.

Although the following is not a publicly known technique, it is a technique studied by the present inventor, and its outline is as follows.

In other words, in puff caging technology using a mold press machine, a cavity of a predetermined shape is formed in a mold consisting of an upper mold and a lower mold, and a thermosetting resin such as an epoxy resin is poured into this cavity at high temperature. The resin is injected under high pressure to harden into a predetermined block shape, and after curing, the mold is opened and the molded package block is taken out.

[Problem that the invention seeks to solve]

However, the inventors have discovered that the above-mentioned mold press technique causes the following problems.

That is, firstly, the heating temperature of the mold is maintained at a constant temperature near the thermosetting temperature of the resin. For this reason, after resin injection starts, before the resin is completely filled into the cavity, the resin has already started to harden near the gate, which is the injection port of the cavity, and this causes voids etc. in the molded package. This may cause mold defects.

Secondly, in the above mold press technology, when taking out the molded package block from the mold, cooling of the mold relies only on the curing and shrinkage of the package, so the resin that makes up the package expands due to ripening. Because of this, there is a problem of poor mold releasability. Another problem is that it takes a long time to remove the molded package from the mold.

Thirdly, as mentioned above, when the molded package is taken out from the mold, the resin constituting the package is in an expanded state due to heat, so there is a problem that the mold releasability is poor.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a technique that can efficiently carry out a highly reliable mold press process.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

That is, a mold in which a cavity is formed is provided with heating means and cooling means whose operation is controlled by a temperature control mechanism.

[Effect]

According to the above means, by controlling the temperature control mechanism, it is possible to achieve optimal temperature conditions in each part of the process, from the start of injection of the thermosetting resin into the cavity, through curing and taking out the package from the mold. Not only can the mold press process time be shortened, but also highly reliable package molding can be performed.

〔Example〕

Fig. 1 is a sectional view showing a mold of a mold press device which is an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the entire mold press device, and Fig. 3 is a temperature control state of this mold press device. FIG.

In this embodiment, this mold press device 1 includes an upper platen 2 fixedly attached to the upper platen 2,
It has a lower platen 3 facing toward and movable toward and away from each other, and both of these platens 2,
3 is supported by a plurality of vertical support columns 4 surrounding both platens 2.3.

The upper platen 2 is provided with an injection cylinder 6 whose reciprocating motion is controlled by the injection control section 5, and the lower platen 3 is provided with a mold opening/closing cylinder 7 whose reciprocating motion is controlled by the mold opening/closing control section 6. .

The mold 8 consists of an upper mold 8a and a lower mold 8b, and the upper mold 8a is fixedly suspended from the upper platen 2 via a support 10a. On the other hand, a lower mold 8b is attached to the lower platen 3 while being supported by a support 1Qab. On both opposing surfaces of these upper mold 8a and lower mold 8b,
When the upper mold 8a and the lower mold 8b are in contact with each other, cavities 13 are respectively formed which become package molding parts.

Further, the lower mold 8b is formed with a cull 14 as a resin receiver, and a runner 15 that communicates the cull 14 with the cavity 13. Note that the runner 15 has a gate 16 formed in an inversely tapered shape near the cavity 13, and has a structure that increases the injection pressure of resin (not shown) into the cavity 13.

The mold 8 is divided into a plurality of blocks 11a and 11b as shown in FIG. 2, taking the lower mold 8a as an example, and a heater 12 is arranged in each block 118, 11b and on the side. The structure is such that each block 11a, 11b is heated from the side. Further, inside each of the blocks 11a and 11b, a sub-heater 12a and a cooling chinive 14 in which a cooling medium' is circulated are installed in the vicinity of the cavity 13, respectively. These heater 12, sub-heater 12a and cooling tube 14
are temperature control units 17 provided outside the mold 8, respectively.
The structure is such that the heating or cooling operation is controlled by the In addition to the sub-heater 12a and the cooling tube 14, a temperature sensor 18 such as a thermocouple is embedded inside the mold 8, and a detection signal from this temperature sensor 18 is sent to the temperature control section 17. ing.

A pot 20 is provided at approximately the center of the upper mold 8a, and a plunger 21 is mounted inside the pot 20 so as to be slidable in the axial direction.

Next, the operation of this embodiment will be explained.

In the state where the upper mold 8a and the lower mold 8b are opened, the lower mold 8
A lead frame (not shown), which is a member to be molded, is placed on the upper surface of the cavity 13 of b.

Next, the mold opening/closing cylinder 7 is operated under the control of the mold opening/closing control if'B6, and the upper mold 8a and the lower mold 8b are closed.

Next, the injection cylinder 6 is operated under the control of the injection control unit 5, and a tablet-shaped and softened resin (not shown) is press-fitted into the pot 20 by the plunger 2, whereby the resin is poured into the runner. 15 and gate 16, and is injected into each cavity 13.

As the resin is injected into the cavity 13, temperature control by the temperature control unit 17 is started, and the heater 12, sub-heater 12a, or cooling tube 14 is activated.

Here, the temperature control of the mold 8 according to this embodiment is performed as shown in FIG. Below, the mold 8 is based on Fig. 3.
temperature control will be explained.

First, in the step of injecting resin into the mold 8, that is, the cavity 13, the temperature of the mold 8 is detected by the temperature sensor 18, and when this detection signal is sent to the temperature control section 17, the temperature of the mold 8 is detected by the temperature sensor 18. Heater 17. The sub-heater 12a or the cooling tube 14 is operated at any time,
The mold 8 is controlled to be at a constant temperature lower than the curing temperature of the resin. In this way, since the mold 8 is controlled to be lower than the curing temperature Q during resin injection A, the injected resin does not harden near the gate 16. The entire area of the cavity 13 is filled with the resin uniformly. Therefore, voids etc. are less likely to occur in the resin.

As described above, when the injection of the resin into the cavity 13 is completed, the process moves to the resin curing step.

In this curing step B, the temperature of the mold 8 is set to a temperature higher than the curing temperature Q of the resin. This does not necessarily have to be higher than the curing temperature Q, but by setting the temperature higher than the curing temperature Q, rapid heating can be achieved by the heater 12 or sub-heater 12a.

In this manner, the resin begins to harden during the process in which the temperature of the mold 8 is raised to the set temperature, and a package corresponding to the shape of the cavity 13 is molded.

When the resin curing process B for a certain period of time is completed, the temperature of the mold 8 is rapidly cooled down to below the curing temperature and close to room temperature under the control of the temperature control section 17, and the process proceeds to the ejection process C.

In this manner, when the mold 8 reaches a temperature close to room temperature, the upper mold 8a and the lower mold 8b are opened, and a molded package (not shown) is taken out. At this time, according to this embodiment, the molded package is in a heat-shrinked state due to rapid cooling, so it can be easily taken out from the mold 8.

As described above, according to this embodiment, the following effects can be obtained.

(1) Heater 12. The sub-heater 12a and the cooling tube 14 are installed internally, and the temperature conditions of the mold 8 can be changed at any time during one cycle of the mold pressing process under the control of the temperature control unit 17, thereby achieving an efficient mold pressing process. can be realized.

(2) Due to (1) above, the temperature condition of the mold 8 can be lower than the curing temperature Q of the resin when injecting the resin.
By suppressing hardening of the resin near the gate 16 during injection, it is possible to prevent package voids from occurring.

[3) Due to (1) above, the temperature of the mold 8 can be rapidly raised during curing, so the curing time of the resin is shorter than when the temperature condition of the mold 8 is kept constant during the mold press process. B can be significantly shortened.

(4) Due to (1) above, after the resin has hardened, the mold 8 can be rapidly cooled to below the curing temperature and to around room temperature, making it easy to remove the molded package from the mold 8 due to thermal contraction of the resin. becomes.

(5) With the above (1) to (4), an efficient and highly reliable mold pressing process can be realized.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, the heating means and the cooling means may be equipped with a heat pipe mechanism.

Further, the temperature control by the temperature control mechanism is not necessarily limited to the temperature control example shown in FIG. 3 of the embodiment.

In the above explanation, the invention made by the present inventor is mainly applied to the field of application, which is a so-called mold press machine for semiconductor devices, but the present invention is not limited to this, and is applicable to other electronic parts, etc. It may also be a mold press device used for package molding.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, a mold that is divided into at least one pair and has a cavity formed in each divided surface into which thermosetting resin is injected, and a heating means and a cooling means that are embedded inside the mold to heat and cool the cavity. and a temperature control mechanism that detects the temperature state inside the cavity and controls the operation of the heating and cooling means over time while injecting the thermosetting resin. From the start of thermosetting resin injection, through the curing of the resin and removal of the package from the mold.
Since optimal temperature conditions can be achieved in each process, the time required for the mold press process can be shortened, and highly reliable package molding can be performed.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a mold of a mold press device according to an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the entire mold press machine of the above embodiment, and Fig. 3 is a mold of the above embodiment. It is an explanatory view showing a temperature control state by a press device. 1...Mold press device, 2...Upper platen,
3... Lower platen, 4... Strut, 5... Injection control section, 6... Mold opening/closing control section, 7... Mold opening/closing cylinder, 8... Mold, 8a... Upper Mold, 8b...Lower mold, 1
0a, 10b...Support, lla, llb...Block, 12...Heater, 12a...Sub heater,
13... Cavity, 14... Cooling tube, 15
... Runner, 17 ... Temperature control section, 18 ... Temperature sensor, A ... Injection process, B ... Curing first
Fig. 2 Fig. 77-Takahashiya 1st grade p16-31L dust Seyu, 47th 3rd FI! J t □

Claims (1)

[Scope of Claims] 1. A mold that is divided into at least one pair, and each divided surface has a cavity in which a thermosetting resin is injected;
A heating means and a cooling means are embedded inside the mold to heat and cool the cavity, and the temperature state inside the cavity is detected and the operation of the heating and cooling means is controlled over time as the thermosetting resin is injected. A mold press device equipped with a temperature control mechanism. 2. The temperature control mechanism controls the operation of the heating/cooling means so that the temperature is at least below the curing temperature when the thermosetting resin is injected into the cavity, the temperature is above the curing temperature after the injection is completed, and the temperature is below the curing temperature after the curing is completed. 2. The mold press apparatus according to claim 1, wherein the mold press apparatus is configured to perform the mold press as described in claim 1.