JPH03173445A - Manufacture and manufacturing equipment for semiconductor plastic package - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for manufacturing a semiconductor plastic package.

[Conventional technology]

Conventional equipment uses a transfer molding machine to mold a semiconductor plastic package, for example, a semiconductor chip mounted on a lead frame, into a resin mold in a heated mold, then opens the mold, and releases the molded product from inside the mold. The molded parts are taken out and left to cool naturally, and then unnecessary cull and runners that become scrap are separated, and after a large number of molded products have accumulated, they are heated again in a heating tank (hot air oven) through batch processing for secondary curing (approximately (at 180°C for about 6 hours).

Incidentally, related to this type of device is discussed, for example, in Oki Electric Research & Development No. 133, ``Development of automatic molded IC through-hole assembly system ``Izanagi,'' published in January 1988.

[Problem to be solved by the invention]

The above conventional technology does not take into consideration issues such as thermal stress caused by temperature changes during the process of taking out the molded semiconductor plastic package from the mold, resulting in large residual stress within the package. .

This has caused problems such as package cracks and lead/resin interface delamination and deformation.6 In addition, many molded products that have been cooled to room temperature are batch-processed (hot air oven, etc.) to perform high-temperature processing (completely complete the molded products). Because of the secondary curing (secondary curing for hardening), the processing time is long and inefficient, and there are also problems such as the inability to fully automate post-processes such as high-temperature processing after molding.

The purpose of the present invention is to solve the above-mentioned conventional problems.The first purpose is to provide a method for manufacturing a semiconductor plastic package that has low residual stress and is less likely to cause resin cracks, and the second purpose is to provide a manufacturing apparatus for the same. The aim is to provide each of these.

The points to be solved by the method and manufacturing apparatus of the present invention are listed below.

(1) After molding is completed, when opening the mold and transferring the molded product into the heating tank, ■ the molded product is not cooled, ■ the transfer can be done in a short time, and ■ the transfer mechanism allows radiant heat in the heating tank. ■The device must be miniaturized.

(2) When performing heat treatment in a heating tank, ■ the necessary heating time can be secured, ■ heating efficiency can be increased to complete heating in a short time, ■ heating can be performed uniformly, and ■ transport can be performed reliably. .

(3) When performing cooling processing using a cooling device, ■ the necessary cooling time must be secured; and ■ transport can be performed reliably.

(4) After taking out the molded product from the cooling device, (1) transport can be performed reliably, and (2) gate break can be performed reliably to separate scraps such as culls and runners from the molded product.

etc. can be mentioned.

[Means to solve the problem]

The first object of the present invention is as follows: (1) A semiconductor element mounted on a lead frame in advance is resin-molded by primary curing using a mold, and after opening the mold, secondary curing is performed by heat treatment. Preferably, the method for manufacturing a semiconductor plastic package includes the step of cooling the semiconductor plastic package after opening the mold, and performing secondary curing in a heated state without cooling. 2) After the mold is opened, the semiconductor plastic package is made by heating with far infrared rays while transporting the resin molded product through primary curing, as a heating method for the secondary curing process while being heated and held without cooling. This is achieved by the manufacturing method. In addition, as said far-infrared rays, wavelength 2-20uTn is preferable.

The second object is to provide a means for taking out a semiconductor plastic package that has been primarily cured in a mold and resin-molded from the mold, and a means for continuously removing the semiconductor plastic package without cooling it. It comprises a means for secondarily curing the semiconductor plastic package while being transported in a heating tank, and a means for cooling the secondarily hardened semiconductor plastic package in a cooling tank, and each of the means is connected by a continuous transporting means. (4) means for taking out from the mold a molded semiconductor plastic package that has been primarily cured and resin-molded in a mold;
A distribution means for distributing and placing the molded products under heating on a conveyance path provided in a single row or in parallel in a plurality of rows that continuously opens and moves in the heating tank and the cooling tank; heating means for secondarily curing the molded products distributed and placed on the transport path by heating during transport; a cooling means for cooling the inside of the tank during transportation; a gate break mechanism for taking the molded product out of the tank from the transport path and separating and cutting off unnecessary parts connected to the molded product; and a storage device for loading molded products into a loading rack.
3) The semiconductor plastic package manufacturing apparatus described in (3) or (4) above further comprises:
), and (6) as a means for taking out from the mold a semiconductor plastic package molded product that has been primarily cured and resin-molded in the mold; (3) and (4) above, which consists of a mechanism in which a take-out bar is buried in a groove in the mold or the take-out bar is taken out by tilting the bar after the mold is opened.
) or by the semiconductor plastic package manufacturing apparatus described in (5), or (7) by configuring the conveyance path with a plurality of wire ropes spaced apart at a predetermined interval and providing a tension adjustment mechanism for each rope. By the semiconductor plastic package manufacturing apparatus described in (3), (4), (5) or (6) above, which is equipped with a function to prevent misalignment of the product, and (8) on the conveyance path running in the heating tank. By the semiconductor plastic package manufacturing apparatus according to (3) or (4) above, in which a thin bar is provided at an angle so as not to block the radiant heat in the heating tank as a distributing means for distributing and placing the molded products, and the delivery is possible. (9) The semiconductor plastic package manufacturing apparatus according to (8) above, in which the molded product can be transferred by arranging thin bars in a pitchfork shape and by sliding on an inclined plane,
achieved.

Furthermore, one means of the present invention will be explained below based on a specific example.

After opening the mold, in order to quickly take out all the primary cured molded products in the mold, a molded product ejection bar is embedded in the mold, and after the mold is opened, the molded product released from the mold is removed from the mold by an in-mold ejector. Take it out by tilting it upward.

The molded products that have been slid on an incline are received by a distribution cart and transported to each conveyance path within a plurality of rows of heating tanks. Next, the molded product on the trolley is fed into the heating tank using a lid provided at the entrance of each conveyance path. Here, the molded product loading section of both the cart and the lifter is composed of a thin inclined bar. The bars are arranged in a rake shape,
They are placed in positions that do not interfere with each other during transfer between the trolley and the lid, and between the lifter and the heating tank conveyor.

A stopper was provided at the tip of the lifter bar to ensure that the molded products placed on the conveyor inside the heating tank were always in the same position.

In order to effectively heat the molded products, heaters were installed on both sides of the running conveyor, and the conveyor used two wire ropes so as not to block the radiant heat applied to the resin molds. That is, the lead frame portion of the molded product was supported by a wire rope so that no shadow was cast on the resin mold portion. Furthermore, the resin mold part acts as a guide and prevents the molded product from shifting in the lateral direction.

The wire rope was moved by a motor or an indexing machine so that it was fed one pitch per tact (one forming operation). In addition, a tension adjustment mechanism was provided for each wire rope to prevent the molded product from shifting due to slack in the rope.

The heating time depends on the number of molded products loaded in the heating tank.
Secondary curing is usually completed in 20 to 30 minutes. If the number of loading positions (number of pitches) becomes too large in the case of one conveyance path,
Since the device would be large, multiple conveyance paths were installed to make the device smaller and to increase heating efficiency. Also, in order to heat evenly,
Multiple heaters were installed to equalize the temperature distribution depending on the loading position of the molded products and to complete heating effectively.

The cooling device also served as a conveyor for heating and conveyance to ensure cooling of the molded products coming out of the heating tank, and the products were cooled by a fan or natural cooling while being loaded on the conveyor.

In addition, to prevent rapid cooling, an intermediate cooling zone may be provided between the heating tank and slow cooling.

To take out the molded product from the heating and cooling conveyance path, a lifter consisting of an inclined bar is raised, the molded product is slid, and transferred onto a storage cart. The storage cart moves to the take-out conveyance path position and receives the molded product.

The storage cart was equipped with a guide around the periphery to position the molded products, and was also equipped with a rotating mechanism to transport the molded products to the gate breaker.

By the above method, the molded product is cooled and accurately positioned, so that the gate breaker can perform reliable gate breaking.

[For production]

According to the present invention, cooling of the molded product can be prevented by shortening the time required to take out the primarily cured molded product from the mold and inserting it into a heating device, and by adding a cooling prevention mechanism. or,
In the heating device for secondary curing, there is no molded article transfer mechanism that blocks radiant heat, so the resin mold part can be heated continuously and uniformly after the mold is opened. or,
By securing the necessary heating time by multiplying the number of conveyor path rows by the number of pitches, it is possible to downsize the device.

The molded product delivery and conveyance mechanism is shaped like a rake and has an inclined sliding mechanism, which allows the device to be made smaller and cheaper.

After the cooling process, a gate break is performed to remove unnecessary scraps such as culls and runners, so the gate break can be performed reliably.

At least, it is possible to automate the whole process from molding to the secondary curing process, and it is possible to automate the pre-molding process to the post-molding process.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the device of the present invention, viewed from the lateral direction. FIG. 2 is a cross-sectional view of the above embodiment viewed from above. FIG. 3 is a plan view showing a state in which molded products are loaded on the conveyor.

The device of the present invention falls into the following zones ■ to ■ when classified by process.
It can be roughly divided into four blocks. below,
Each zone will be explained in turn.

Zone I includes a transfer molding machine 1 for molding a resin molded semiconductor through primary curing, a conveyance device for conveying the molded product 4 to zone H, and a heater for heating the molded product 4 so that it does not cool down during transportation. 32.33.

After molding, the molded product 4 is placed on the lower mold 2 which has been separated from the upper mold 3 (hereinafter this operation will be referred to as mold opening). This molded product is released from the mold by an ejector turbine (shown clearly in FIG. 5, which will be described later) provided in the lower mold at the same time as the mold is opened. In order to take out the molded product 4 placed on this lower mold 2 from inside the mold 5
A molded product take-out bar 5 and a cylinder or motor 6 for driving the take-out bar are provided. The take-out bar 5 is arranged such that a groove is provided in the lower mold 2, embedded therein, and the molded product 4 is placed thereon. Hereinafter, the operating mechanism until the molded product 4 is transported to zone (2) by the transport device will be described in detail. After opening the mold, the cylinder (or motor) 6 removes the ejection bar 5.
When tilted upward, the molded product 4 slides on the take-out bar 5,
It is transferred onto the sorting cart 7.

The sorting cart 7 is moved by a cylinder or a motor 8 for moving the cart into each transport path (four transport paths 16-1 to 16-4 in the illustrated example of FIGS. 2 and 3) provided in the heating tank 11 of zone path) position.

If there is one line of conveyance path in the heating tank 11, the moving cylinder (or motor) 8 of the cart 7 is unnecessary, and in this case, it may be in a fixed position. After the sorting cart 7 moves to the transport path position to be inserted into the heating tank 11, the tank and inner insertion bar 9 provided in each corresponding transport path heating tank 11 is raised by a driving cylinder or motor 1o. The bar 9 is inclined and receives the molded product 4 on the sorting cart 7 and slides toward the heating tank 11. Next, this bar 9 is connected to the cylinder (or motor) 10
When the molded product 4 is lowered by
They are loaded onto a conveyor 16 provided inside.

Zone (2) is an area where the molded product 4 is subjected to heat treatment for secondary curing while continuing to be moved.

The conveyor 16 has a motor or an index (indexing machine) 2
0, the mechanism is such that only the selected conveyance path is moved by one pitch every takt (one molding operation) via the drive pulley 19.

Inside the heating tank 11, there are heating heaters 12.13.14.1.
5 is provided so that the molded product can be heated from both sides. The heating tank 11 is provided with partitions 11a'''cA so that the heating temperature can be changed.

It is divided into chambers B, and the temperature can be controlled in stages. This heater preferably uses far infrared rays (wavelength 2 to 20 nm) such as a ceramic heater, and
Secondary curing can be completed by processing at 50 to 230°C for 20 to 30 minutes.

The heated molded product 4 is transferred by the conveyor 16 to the cooling device 17 in zone (2). Here, it is cooled by natural cooling or by the fan 23.

The molded product 4 that has been completely cooled is further transferred by the conveyor 16 to the out-of-tank removal position of the next zone (2).

Zone (2) is a recovery area for molded products, and when the molded product 4 comes to the take-out position, the storage cart 24 is moved to the take-out conveyance path position by a cylinder or motor 26, and the lifter 21 for taking out of the tank is moved by the cylinder or motor 22. Increase by Lifter 21
is composed of an inclined bar, and as shown in FIG. 2, only molded products are taken out using rods arranged on both sides of the conveyor 16 and moved onto the storage cart 24 without interfering with the conveyor 16. Next, when the lifter 21 is lowered, the molded product 4 is moved to the storage cart 2.
4 is loaded on top. The storage cart 24 loaded with the molded product 4 is moved by the cylinder or the motor 25 to the unloading position to the gate breaker 27, is rotated to the gate breaker position by the swing motor 25, and after holding the molded product on the gate breaker 27 side, It is returned to the lifter 21 side. gate breaker 2
The molded product 4 held in step 7 is subjected to gate breaking (separation of the cull and runner from the resin mold part of the molded product), and the cull and runner are disposed of outside as scrap, and the resin mold part is stored as the final product. rack 28
They are inserted and loaded one after another. A moving motor 29 for sequentially inserting the products into the storage rack groove, a delivery device 30 for sending the storage rack to the next process, and a driving cylinder or motor 31 are provided to move the storage rack to the next process.

Figures 4 and 5 are the lower mold 2 shown in Figures 1 and 2.
FIG. 4 is an enlarged plan and side view of a mechanism for taking out the molded product 4 inside.

A groove is provided in the lower mold 2, and a thin molded product ejection bar 5 is installed here.
By embedding the bar 5 and lifting the bar 5 after opening the mold, the molded product 4 can be quickly taken out from the mold 2. In addition, a configuration may be adopted in which an ejector turbine 5, which is a dedicated device for ejecting, is embedded in the mold 2, and the ejecting turbine 5 is raised and lowered to facilitate ejection from the mold.

The transport mechanism between each zone will be further explained in detail with reference to FIGS. 6 to 10.

FIGS. 6 and 7 are an enlarged plan view and side view of the conveyance mechanism for inserting the molded product 4 into the heating tank 11 shown in FIGS. 1 and 2. FIG.

The molded product 4 on the sorting cart 7 is raised by an insertion mechanism composed of a thin inclined insertion bar 9, transferred to the heating tank 11 side, and then lowered to the heating tank 11. They can be placed accurately on a conveyor 16 consisting of a wire rope conveyance path provided inside.

Figure 8 shows the conveyance path inside the heating tank using two wire ropes 1.
6 is a diagram showing a state in which the molded product 4 is mounted.

That is, the molded product 4 can be prevented from shifting by being guided by two wire ropes 16.

Figures 9 and 10 show tank 1 shown in Figures 1 and 2.
FIG. 3 is an enlarged plan view and a side view showing a molded product recovery mechanism in zone (2) where molded products 4 are taken out of the tank from heating and cooling conveyance paths Nos. 1 and 17;

The molded product 4 on the conveyor 16 is raised by the lifter 21 for taking it out of the tank, which is made up of a thin inclined bar, and the storage cart 2
4 side and then lowered to ensure that it is mounted on the storage cart 24.

In other words, the combination of rake-shaped bars makes it possible to carry out reliable transportation in a space-saving manner.

FIG. 11 is a diagram showing the processing procedure of the semiconductor plastic package manufacturing apparatus according to the present invention.

The unique feature is that after opening the mold, the molded product is heated while being transported without being cooled, and after heating is complete, a cooling process is performed, followed by a gate break.

〔Effect of the invention〕

According to the present invention, residual stress generated within the package can be reduced and product reliability can be improved. In addition, it is possible to shorten the heat treatment time and automate the integrated process from molding to heat treatment, allowing continuous processing to be carried out to subsequent processes, and greatly improving production efficiency.

Furthermore, the device can be downsized and an economical device for manufacturing semiconductor plastic packages can be provided.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of an embodiment of the manufacturing apparatus of the present invention seen from the front, Fig. 2 is a cross-sectional view of the manufacturing apparatus of Fig. 1 seen from above, and Fig. 3 is a heating diagram of Fig. 2. A plan view showing a state in which formed products are loaded on a conveyor in a tank; FIGS. 4 and 5 are a plan view and a side view showing a molded product ejection mechanism in which a groove is provided in the mold and a thin bar is embedded; Figures 6 and 7 are a plan view and a side view showing a conveyance device in which the conveyance path in the heating tank is a wire rope, and the molded product is inserted into the tank by a thin inclined bar, and Figure 8 is the above-mentioned A cross-sectional view of the wire rope conveyance path, and FIGS. 9 and 10 are a plan view and a side view showing a conveyance device that sequentially transfers the molded products in the tank conveyance path by arranging thin bars tilted in a pitchfork shape. , and FIG. 11 is a diagram showing the processing procedure of this manufacturing apparatus. 1... Transfer molding machine 2... Lower mold 3... Upper mold 4... Molded product 5... Molded product take-out bar 6... Cylinder or motor 7... Sorting truck 8 ... Cylinder or motor 9 ... Bar for insertion into the tank 10 ... Cylinder or motor 11 ... Heating tank 12.13.14.15 ... Heating heater 16 ...
In-tank conveyor 17...Cooling tank 18...Rope tension adjustment mechanism 19...Active pulley 20...Motor or index (indexing machine) 21...
・Lifter for taking out the tank outside 22...Cylinder or motor 23...Fan 24...Storage cart 25・
...Swivel motor or cylinder 26...Cylinder or motor 27...Gate breaker 28...Storage rack 2
9... Rack lifting motor 3o... Feeding device 31... Cylinder or motor

Claims (1)

[Claims] 1. A process of resin molding a semiconductor element mounted and mounted on a lead frame in advance through primary hardening using a mold, and after opening the mold, performing secondary hardening through heat treatment and allowing it to cool. A method for manufacturing a semiconductor plastic package comprising the step of performing secondary curing in a heated state without cooling after opening the mold. 2. After opening the mold, the heating method in the step of performing secondary curing without cooling is performed by heating with far infrared rays while conveying the resin molded product by primary curing. A method of manufacturing the semiconductor plastic package described. 3. Means for taking out the resin-molded semiconductor plastic package from the mold after primary hardening in the mold, and secondary curing while continuously transporting the semiconductor plastic package in the heating tank without cooling it. 1. A semiconductor plastic package manufacturing apparatus comprising means for cooling the secondarily cured semiconductor plastic package in a cooling tank, and a continuous conveyance means connecting the means. 4. A means for taking out the semiconductor plastic package molded product which has been primarily cured in the mold and resin-molded from the mold, and a single row or multiple parallel rows for continuously driving the inside of the heating tank and the cooling tank. a distribution means for distributing and placing the molded articles under heating on a conveyance path provided in a heating tank; a heating means for secondary curing, a cooling means for cooling the molded product which has been secondarily hardened by the heating while being transported through a cooling tank provided adjacent to the heating tank, and a cooling means for cooling the molded product from the transport path. The molded product has a gate break mechanism that takes it out of the tank and separates and cuts off unnecessary parts connected to the molded product, and a storage device that loads the molded product processed by the gate break mechanism into a loading rack. 4. The semiconductor plastic package manufacturing apparatus according to claim 3. 5. The apparatus for manufacturing a semiconductor plastic package according to claim 3 or 4, wherein the heating means comprises a heater that emits far-infrared radiation with a wavelength of 2 to 20 μm. 6. As a means for taking out the molded semiconductor plastic package that has been primarily cured and resin-molded in the mold, a take-out bar is embedded in the mold or by providing a groove in the mold. 6. The semiconductor plastic package manufacturing apparatus according to claim 3, further comprising a mechanism for tilting and taking out the bar after opening the mold. 7. Claims 3, 4, 5, or 6, wherein the conveyance path is constituted by a plurality of wire ropes spaced at a predetermined interval, and a tension adjustment mechanism is provided for each rope to prevent misalignment of the molded product. The semiconductor plastic package manufacturing apparatus described above. 8. Claim 3 or 4, wherein the distributing means for distributing and placing the molded products on the conveyance path running in the heating tank is provided with a thin bar inclined so as not to block the radiant heat in the heating tank so as to enable delivery. The semiconductor plastic package manufacturing apparatus described above. 9. The semiconductor plastic package manufacturing apparatus according to claim 8, wherein the molded product can be transferred by arranging thin bars in a pitchfork shape and by sliding on an inclined plane.