JPS6258546B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a package forming assembly device for sealing semiconductor elements such as diodes and transistors, and integrated circuits of these semiconductors (hereinafter referred to as semiconductors). Two pre-formed thermoplastic resin plate-shaped molded products (hereinafter referred to as plate-shaped molded products), at least one of which has a recess for accommodating semiconductors, are heated while being supplied to a mold section for combination. The present invention relates to a combination device for molding packages such as thermoplastic resin flat packages and dual-in-line packages, which is characterized in that the lead frames on which semiconductors are mounted are then sandwiched and integrated under pressure.

Conventional resins for sealing semiconductors include:
Thermosetting resins such as epoxy and silicone are mainly used, and the molding methods using these resins include so-called transfer, casting, dipping, potting, etc. They are used differently depending on the situation. Among them, transfer molding using epoxy resin is a typical method.

Compared to packages called hermetic seals that use ceramics or metals, plastic packages that use plastics such as epoxy resin are cheaper because they seal and mold multiple lead frames with semiconductors attached at once. On the other hand, it had a fatal drawback in terms of the process because the resin used was a thermosetting resin.

In other words, packages using these thermosetting resins require a heat aging process lasting several hours, called a post-cure process, in order to more completely cure the resin after sealing and molding, and for this reason, it is difficult to incorporate semiconductor elements into the package. From the process of dividing the wafer into chips, to the die bonding process of fixing the chips to the mounting part of the lead frame, the wire bonding process of making the chip electrodes conductive to the leads,
This method has a very large drawback in that it is difficult to seamlessly connect and automate the assembly process, including the resin sealing process, the lead post-processing process, and the marking process.

The present invention has been made in view of these drawbacks, and the details thereof will be explained below with reference to FIGS. 1 to 13 showing one embodiment of the present invention. In Figures 1-a, 1-b, and 1-c showing the outline of the apparatus, 1 and 1' are combining mold parts having rotating shafts 6 and 6' at their centers, respectively. An equilateral rectangular prism with cavities 2, 2', cavities 3, 3', cavities 4, 4', and cavities 5, 5' for supplying a plate-shaped molded product on the side surface. It has a shape.

It should be noted that the term "equal-sided rectangular prism" as used herein means that in FIG. 11, the virtual surface 35 shown by the dotted line and the clamping surface 34 shown by the solid line forms an equilateral rectangular prism. That is, the two merging mold parts of the present device may be of any type as long as the virtual surface including the clamping surface with the cavity forms the side surface of an equilateral polygonal prism.

The meaning of each cavity in the positional process in the above drawings is that the cavity is a clamping and joining process, the cavity is a heating process, the cavity is a preheating process, and the cavity is a feeding process of a plate-shaped molded product.

The number of cavities provided on each side of the equilateral rectangular prism is 1.
It is not limited to 1, but any number can be selected. That is, when there are at least two cavities, the cavities can be arbitrarily arranged in the axial direction and rotational direction of the rotating shaft, and when there are at least four cavities, the cavities can be arranged uniformly in the axial direction and rotational direction of the rotating shaft, respectively. The number may be evenly arranged at the same position on each side.

The two joining mold parts 1 and 1' are the lead frame 7
8 and 8' are in opposing positions with the two mold parts 1 and 1' being pressed together, and of the two mold parts 1 and 1', the mold part 1 for combination above the lead frame 7 is lowered, while the mold part 1 for combination is lowered. The lower joining mold part 1' is a lead frame holding press device for lifting up and holding the lead frames 7 facing each other at the same time. The lead frame holding press devices are integrated with the combining mold parts 1 and 1' via rotating shafts 6 and 6', respectively, and are reciprocated by air cylinders 9 and 9'.

By having a lead frame holding press device that simultaneously holds such lead frames facing each other using two joining mold parts, the plate-shaped molded product can be uniformly pressed against the lead frame surface from above and below. This is extremely effective in preventing deformation of the lead frame and damage to semiconductor connections. In addition, as long as the two mold parts 1 and 1' are rotatable around the rotating shafts 6 and 6', the press device for holding the lead frame can be integrated with the two mold parts 1 and 1'. It may be either a structure or a removable structure. As a synchronizing means for simultaneously holding the lead frames facing each other, as shown in FIG.
Two racks 17, 17' connected to each other are arranged in contact with a rotatably mounted pinion 18. However, the synchronizing means for simultaneously holding the parts facing each other is not limited to this, and a link mechanism, a cam device, etc. may be used instead. In the case of using a link mechanism, two elements 19 and 19' each connected to a press device for holding two lead frames as shown in FIG. A link mechanism connected by a rotating rotating element 20 is conceivable. In addition, in the case of a device using a cam device, for example, as shown in FIG. A cam device rotating around an axis 24 and in contact with a symmetrical cam 23 having a cam profile symmetrical with respect to the cam axis, and a press device for holding two lead frames as shown in FIG. A cam device is conceivable in which two connected followers 22, 22' are reciprocated in a direction parallel to the clamping surface and brought into contact with a symmetric end face cam 25 having a cam profile symmetrical with respect to the clamping surface.

Note that "at the same time" here refers to the time when the clamping surface 34 of the joining mold part 1 contacts the lead frame 7 and the time when the joining mold part 1' comes into contact with the lead frame 7 in FIGS. 1-b and 1-c.
This means that the times when the clamping surfaces 34' of the lead frame 7 contact the lead frame 7 substantially coincide with each other.

In addition, the clamping surfaces 34 of the two joining mold parts 1, 1',
The means for 34' to hold the lead frame 7 facing each other is not limited to devices that hold the lead frame 7 at the same time, and as described above, measures are taken to prevent deformation of the lead frame, damage to the wiring of semiconductors, etc. To the extent possible, it may be a device that clamps the lead frames one after the other.

That is, it is a device in which either one of the two merging mold parts 1, 1' first comes into contact with the lead frame without damaging it, and then the remaining merging mold parts clamp the lead frame one after the other. Also good. In this case as well, the clamping surface of one of the merging mold parts is in contact with the lead frame just before the clamping is completed, so the lead frame is fixed more reliably, and the clamping surface of one of the merging mold parts is then fixed by contact with the other merging mold part. This reduces the chance of deformation of the lead frame upon completion, and has the effect of preventing damage to the connections of semiconductors. Furthermore, as a device for holding the lead frame in succession, followers 22 and 22' connected to two press devices for holding the lead frame as shown in FIG.
Two asymmetrical cams 26, 26' having the same cam profile that are asymmetrical with respect to 4, 24' are fixed at different positions or coaxially (not shown) with the two cam shafts 24, 24' respectively. and two asymmetric cams 26, 26' rotating around the camshaft.
There is a cam device in contact with each.

Further, as shown in FIG. 7, followers 2 each connected to a press device for holding two lead frames
2, 22' are two asymmetrical cams 26 having different cam profiles asymmetrical to the camshafts 24, 24';
26', two asymmetric cams 26 whose camshafts 24, 24' are fixed at different positions or coaxially (not shown) and rotate around the camshafts;
It may also be a cam device in contact with 26'. Further, in the case where a cam device is used, two followers 22, 22' are connected to two lead frame clamping press devices as shown in FIG.
A cam device that reciprocates in a direction parallel to the clamping surface and is brought into contact with an asymmetric cam 27 having an asymmetric cam profile with respect to the clamping surface, or a cam device for clamping two lead frames as shown in FIG. Two followers 22, 22', each connected to a press device, are fixed to a camshaft 24, swing around the camshaft, and come into contact with a swinging cam 28 having an asymmetric cam profile with respect to the camshaft. It may also be a cam device with a

The two lead frame holding press devices are
Regardless of whether the lead frame is clamped by the separate joining mold parts at the same time or one after the other, even if the structure is such that each unit is driven by its own press drive source, or if the two press devices are driven by a single press drive source, It may also be a structure that drives.

FIG. 10 shows a lead frame clamped by a lead frame clamping press device, and each cavity provided in the "merging mold parts 1, 1'"
(2, 2'; 3, 3'; 4, 4'; 5, 5') A push rod 30 is integrated with a stripper 31 by a fixture 32, and a spring 33 interposed between the push rod and the stopper provides a press recovery function.

As shown in FIG. 10, the push rod 30 has such a shape that the projected shape of the end surface of the portion of the plate-shaped molded product 29 in contact with the push rod 30 is included in the projected shape of the end surface in the pressing direction. Because the push rod 30 has such a shape, the local load of the push rod 30 when pressing the plate-like molded product 29 housed in the cavity against the lead frame can be reduced. This is extremely effective in preventing the plate-shaped molded product 29 from being deformed, that is, from being depressed in accordance with the shape of the end of the push rod 30.

Further, as shown in Fig. 1-a to Fig. 1-c, this device is used for combining mold parts 1 and 1' prior to pressurization and integration.
It has hot air heaters 10, 10' and hot air heaters 11, 11' for heating the plate-shaped molded product 29 supplied to cavities (3, 3'; 4, 4') in a non-contact state.

Each of the hot air heaters has an integrated structure with a press device 8, 8' for holding the lead frame, and the distance between the hot air heater and the plate-shaped molded product supplied to the cavities 4, 4' is always kept equal. be.

Cavities 5 and 5' are cavities into which a plate-shaped molded product is fed prior to pressurization and integration, and the plate-shaped molded product is fed by chargers 12 and 12'. Reference numerals 14 and 15 are feeding devices for the lead frame 7. It is synchronized with the rotation of the combining mold parts 1, 1' by pulse motors 13, 13' connected to the rotating shafts 6, 6' of the combining mold parts 1, 1', and is used for pressurized integration. The lead frame 7 is supplied one stroke at a time by a hook 14 which is previously connected to an air cylinder 15. In addition, the rotation drive source is a pulse motor,
The reciprocating drive source is not limited to an air cylinder. Note that "synchronization" here means that the rotation of the joining mold parts 1 and 1' is completed before the next clamping, pressurizing, and integrating.
This also means that the feeding of the lead frame has ended. A heating plate 16 is used to heat a predetermined number of traces of the lead frame 7 in contact with each other prior to pressurization and integration.

A step of heating and melting the joining surface of a plate-shaped molded product using the combining device for semiconductor package molding having the above configuration, and then sandwiching the lead frame and pressurizing and integrating it with two mold parts for combining. Figures 1-a to 1
The following process will be explained based on FIG. 1-c and FIG.

(a) A plate-shaped molded product 29 is supplied to cavities 5 and 5' by chargers 12 and 12'.

(b) The two joining mold parts 1, 1' are moved around the rotating shafts 6, 6' by the pulse motors 13, 13'.
Rotate 90 degrees and hook 14 the lead frame 7.
Sends one recording.

(c) The combined surface of the plate-shaped molded product 29 is heated with a hot air heater,
10 and 10' in a non-contact state.

(d) The two mold parts 1 and 1' for combination are rotated by the pulse motors 13 and 13' about the rotation shafts 6 and 6', and the lead frame 7 is fed by one stroke by the hook 14.

(e) The combined surface of the plate-shaped molded product 29 is heated with a hot air heater,
11, 11' heat and melt in a non-contact state. During this time, one stroke of the lead frame 7 is heated by the heating plate 16.

(f) The two joining mold parts 1, 1' are moved around the rotating shafts 6, 6' by the pulse motors 13, 13'.
The lead frame 7 is rotated by 90 degrees and the hook 14 feeds the lead frame 7 by one stroke.

(g) 1 of lead frame 7 heated in (e)
The sandwiching surface 34 of the two mold parts 1 and 1'
Sandwich at 34'.

(h) The plate-shaped molded product 29 housed in the cavities 2 and 2' is pressed onto the lead frame 7 by the push rod 30 and integrated.

This apparatus is a combination apparatus for molding packages of semiconductors, which is characterized in that it continuously integrates a pair of plate-shaped molded products and a lead frame under pressure by repeating the above-mentioned steps.

As already detailed, the process from heating and melting the merging surfaces of the plate-shaped molded products using this device to sandwiching the lead frame and pressurizing and integrating them with the two merging mold parts can be roughly divided into the following steps: become that way. That is, (1)
These steps are: supplying the plate-shaped molded product to the cavity, (2) heating the joining surface with a hot air heater, and (3) pressurizing and integrating the plate-shaped molded product supplied to the cavity.

This device has a rotating mechanism for the two merging mold parts, and a cavity for feeding at least three plate-shaped molded products so that at least the three processes described above can proceed simultaneously. Therefore, it has the great advantage that the three steps mentioned above can be performed continuously and simultaneously. Furthermore, since the two merging mold parts have a rotation mechanism, the position of the cavity can be moved smoothly between processes, reducing the time required for pressurization and integration, and melting the merging surfaces of the plate-shaped molded products. This device has a great effect on obtaining good sealing performance that is easy to maintain close to the desired desired joining conditions, and is highly reliable.This device smoothly connects each step of the assembly process and enables consistent automation. It became possible to measure it.

The two merging mold parts used in the present invention must be equilateral polygonal prisms. The shape of the solid line shown in FIG. 11 is naturally included in the equilateral polygonal prism of the present invention, and is the first shape.
The merging mold part shown in the embodiment of the present invention illustrated in FIG.

The cavities for supplying the plate-shaped molded products of the two joining mold parts used in the present invention are arranged on each side of the equilateral polygonal prism. If there are at least four cavities, a certain number of cavities are arranged at the same position on each side in the axial direction and rotational direction of the rotating shaft. Naturally, the same number of rows of cavities as the number of rows of cavities arranged in the rotational direction of the rotary shaft, which is the same direction as the feeding direction of the rotary shaft, is fed at one time.

The heating means for heating the plate-shaped molded product in a non-contact state used in the present invention is not limited to heating with hot air, but can be any means capable of softening and melting the combined surfaces of the plate-shaped molded product in a short period of time. Radiant heating or the like can be preferably used as long as it is available.

The heating means for heating the lead frame used in the present invention is not limited to a heating plate that heats in a contact state, but also preferably a heating means that heats in a non-contact state, such as heating with hot air or radiation heating. can be used.

Various types of thermoplastic resins are used in the present invention depending on the characteristics required for the package of each semiconductor type, but the thermoplastic resins have high heat resistance (heat deformation resistance and heat deterioration resistance), low moisture permeability, and constant In addition to electrical and mechanical properties that exceed standards, it is also necessary to have moldability that exceeds a certain level.

Typical examples are polyphenylene oxide,
A grade with low water absorption among ether resins such as polyether sulfon, polysulfon, phenoxy resin, and polyacetal, ester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyarylate, carbonate ester resins such as polycarbonate, and polyamide resins. Examples include resins such as polyphenylene sulfide, and combinations of some of these resins and fillers, mainly glass fibers.

As detailed above, according to the present invention, the following effects can be obtained.

(1) Since the two merging mold parts have a rotation mechanism, after heating and melting the joining surface of the plate-shaped molded product, the lead frame is sandwiched and the two merging mold parts are pressurized and integrated. The process can be shortened by being able to process several steps continuously and simultaneously.
It has become possible to automate the mass production of semiconductor packages. Furthermore, by linking it with a wire bonder, it has become possible to automatically assemble thermoplastic resin flat packages, dual in-line packages, etc.

(2) Since it has become possible to extremely shorten the time required from the end of heating to pressurization and integration, the drop in temperature of the heated joining surfaces can be suppressed as much as possible, ensuring strong joining, resulting in high reliability. It became possible to manufacture packages for semiconductors.

[Brief explanation of the drawing]

The drawings all show an embodiment of the combining device for molding semiconductor packages according to the present invention, and FIG. 1-a is a perspective view with a part of the device omitted, and FIG. 1-b is a cut-away view of the casing. Figure 1-c is a cross-sectional view of ABCD in Figure 1-b, Figure 2 is a plan view of the rack and pinion mechanism, Figure 3 is a plan view of the link mechanism, and Figure 4 is a symmetrical cam. 5 is a plan view of a cam device using symmetric end cams, FIG. 6 is a plan view of a cam device using two identical asymmetric cams, and FIG. 7 is a plan view of a cam device using two identical asymmetric cams. FIG. 8 is a plan view of a cam device using asymmetric end cams, FIG. 9 is a plan view of a cam device using a swing cam, and FIG. 11 is a plan view of a virtual equilateral polygonal prism, and FIG. 12 is a perspective view showing the state of a pressurized integrated semiconductor package. It is. Explanation of symbols, 1, 1'...Mold part for combination, 2,
2'... Cavity, 3, 3'... Cavity, 4, 4'... Cavity, 5, 5'... Cavity, 6, 6'... Rotating shaft, 7... Lead frame, 8, 8'... ...Press device for holding lead frame, 9,9'...Air cylinder, 10,1
0'... Hot air heater, 11, 11'... Hot air heater, 12, 12'... Charger, 1
3, 13'...Pulse motor, 14...Hook, 15...Air cylinder, 16...Heating plate, 1
7,17'...Rack, 18...Pinion, 1
9, 19'... Element, 20... Rotating element, 21... Central axis, 22, 22'... Follower,
23... Symmetrical cam, 24, 24'... Cam shaft, 2
5... Symmetrical end cam, 26, 26'... Asymmetric cam, 27... Asymmetric end cam, 28... Rocking cam, 29... Plate shaped product, 30... Push rod, 31... Stripper, 32... ...Fixing tool, 3
3... Spring, 34, 34'... Clamping surface, 3
5...Virtual surface.

Claims (1)

[Scope of Claims] 1. Two thermoplastic resin plate-shaped molded products, at least one of which has a recess for accommodating semiconductors,
In a combining device for molding semiconductor packages, which heats the supply to the cavities of two combining molds and then sandwiches and pressurizes the lead frame on which the semiconductors are mounted, (1) One combining mold. When the number of sides of the side surface (pressing surface) of the part is A, the total number of cavities is B, and the number of cavities arranged in the same number on each side surface is C, then A≧3 and an equilateral polygon satisfying A=B/C. (2) a drive for rotating the two merging mold parts in a fixed direction by 360/A degree using an axis passing through the center of the merging mold parts as a rotation axis; (3) a lead frame clamping press device for sandwiching the lead frame between the two merging mold parts, and (4) a thermoplastic resin plate-shaped molded product in the cavity of the two merging mold parts. (5) a press device for pressing a thermoplastic resin plate-shaped molded product for pressing the thermoplastic resin plate-shaped molded product supplied to the cavity onto a lead frame; and (6) a press device for pressing the thermoplastic resin plate-shaped molded product supplied to the cavity; (7) a thermoplastic resin plate-shaped molded product heating device that heats the plastic resin plate-shaped molded products prior to pressurizing and integrating the two; (8) A heating device that heats at least one pass of the lead frame prior to pressurization and integration. Combining equipment for molding packages of semiconductors. 2. The combination for molding a package of semiconductors according to claim 1, wherein at least two cavities are arranged in the axial direction of the rotating shaft on each side of the equilateral polygonal prism of the two mold parts for combination. Device. 3. The combination for molding a package of semiconductors according to claim 1, wherein at least two cavities are arranged in the rotational direction of the rotation axis on each side of the equilateral polygonal prism of the two mold parts for combination. Device. 4 On each side of the equilateral polygonal prism of the two merging mold parts, at least four or more cavities are arranged at the same position on each side in a fixed number in the axial direction of the rotating shaft and in the rotational direction of the rotating shaft. A device for forming packages of semiconductors according to claim 1. 5. A device for forming packages of semiconductors according to claim 1, wherein the lead frame holding press device includes a device for simultaneously holding the lead frame between two combining mold sections. 6. A semiconductor device according to claim 1, wherein the lead frame holding press device for holding the lead frame oppositely between the two merging mold parts includes a device for holding the lead frames one after the other. Combining device for package molding. 7. The pressing part of the press device for pressing a thermoplastic resin plate-shaped molded product has a shape such that the end face projection shape of the portion of the thermoplastic resin plate-shaped molded product in contact with the pressing part is included in the end face projected shape in the pressing direction. A device for forming packages of semiconductors according to claim 1. 8. The device for forming packages of semiconductors according to claim 1, wherein the heating means for heating the thermoplastic resin plate-shaped molded product in a non-contact state is hot air. 9. The device for forming packages of semiconductors according to claim 1, wherein the heating means for heating the thermoplastic resin plate-shaped molded product in a non-contact state is radiation.