JPH04293243A - Metal mold equipment for resin seal and cutting method of gate - Google Patents

Abstract

PURPOSE:To prevent the damage of a molded object like the package of a semiconductor device, in the case of gate breaking. CONSTITUTION:A metal mold equipment is constituted as follows. A punch 1 is equipped with an upper cavity 1a and an upper gate 1b linked with the cavity 1a. The upper gate 1b has a constricted part 3 adjacent to the upper cavity 12a. A lower die 2 is equipped with a lower cavity 2a and a lower gate 2b linked with the cavity 2a. The lower gate 2b has a first constricted part 4 adjacent to the lower cavity 2a, and a second constricted part 5 facing an opposite side 1c of the upper gate 1b. The cutting method of a gate constituted as follows. When a molded object 6 resin-sealed by said metal mold equipment is subjected to gate breaking, firstly cutting is performed at the position where the opposite side 1c of the upper gate 1b faces the second constricted part 5, and secondly, the cutting is performed at the position where the constricted part 3 faces the first constricted part 4.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a mold device for resin encapsulation and a method for cutting a gate, and in particular, the present invention relates to a mold device for resin encapsulation and a method for cutting a gate, and in particular, the gate is broken in two steps by providing two constrictions in the gate, and is used to package semiconductor devices. This invention relates to a mold device for resin sealing that prevents molded products from being damaged, and a gate cutting method.

[0002] In recent years, the development of semiconductor devices has been remarkable, and the fields in which semiconductor devices are used are expanding rapidly, and their production quantities are also increasing dramatically. The mass production of semiconductor devices is largely dependent on manufacturing technology for a series of manufacturing processes from the wafer stage to the finished product as a semiconductor device.

[0003] The IC manufacturing process can be broadly divided into a pre-process and a post-process. The pre-process is from the wafer stage to the formation of a large number of fine elements, and the post-process is the cutting of the wafer into chips. From the beginning to the finished product.

On the other hand, the post-process can be subdivided into an assembly process and an inspection process, and the assembly process includes cutting the wafer into chips, mounting, bonding, sealing, and marking. Among these, the chip sealing process involves packaging the chip to protect the element and take out the lead-out terminals, and various forms and methods are employed. However, because of its high manufacturing efficiency and low cost, resin packages using resin sealing using molding technology are often used.

However, as semiconductor devices are becoming increasingly large in capacity and highly functional, the patterns of elements formed on the chip are becoming finer, while the number of leads led out from the chip is increasing. , the shape of the package is also getting larger. Therefore, how to efficiently and reliably encapsulate chips with resin has become an important issue from the standpoint of determining the manufacturing cost of semiconductor devices.

[0006]

[Prior Art] Generally, semiconductor devices sealed with resin are
First, a chip is mounted on a stage of a frame-shaped support member called a lead frame, and wire bonding is performed between the chip and terminal portions called inner leads using gold wire or the like. The lead frame on which this chip is mounted and wire-bonded is set in a sealing mold, and then a sealing resin is poured into it, and resin sealing is performed using a type of insert molding.

FIG. 3 is a perspective view of a main part of an example of a conventional mold apparatus for resin sealing, and FIG. 4 is an enlarged view of the Y section in FIG. 3, where (A) is an enlarged perspective view and (B) is a Z- It is an enlarged sectional view of Z. In the figure, 1b is an upper gate, 2 is a lower mold, 2a is a lower cavity, 2b is a lower gate, 6 is a molded product, 7 is a runner, 8 is a lead frame, and 9 is a resin.

The case of resin sealing of a semiconductor device will be explained below as an example. Semiconductor devices, like other electronic components,
It is necessary to mold with precision and low molding pressure. Therefore, for example, transfer molding using a thermosetting resin such as epoxy resin is used. Among these, low-pressure encapsulation molding, which allows low-pressure molding, is generally used especially for electronic parts.

Therefore, the mold apparatus shown here is a type of mold for transfer molding, and has a split mold structure in which a lower mold 2 and an upper mold (not shown) abut against each other. 3 and 4, the lower mold 2 is provided with a plurality of lower cavities 2a so that a plurality of molded products 6 called packages can be obtained at the same time.
The resin 9 flows through the lower gate 2b from the runner 7, which is a runner through which the resin 9 flows.

[0010] Furthermore, an upper mold (not shown) is also provided with an upper cavity opposite to the lower cavity 2a of the lower mold 2, and when both molds are fitted, the molded product 6 is formed by the combined upper and lower cavities. The shape of is now determined.

In the case of a semiconductor device, the lead frame 8 on which the chip is mounted is connected to a loading frame 10.
It is carried while being held in a holder called a holder, and placed on the lower mold 2. Then, the resin 9 is sandwiched between the upper mold and the resin 9.
is poured from the lower gate 2b of the lower mold 2 to perform molding.

[0012] As described above, in the past, mold apparatuses in which the resin 9 was formed only from the lower gate 2b provided on the lower mold 2 were often used. Then, the lower cavity 2a and the lower gate 2
Between b is a so-called chocolate break with a narrow shape (
(hereinafter abbreviated as chocolate break), Runner 7
The molded products 6, which are arranged side by side and molded with resin, can be bent manually, for example, to easily separate the gate, a so-called gate break.

However, recently, as semiconductor elements formed on chips have become larger in capacity and more sophisticated, the number of leads led out from the chip has been increasing, and the shape of the leads has become thinner and the spacing between them has become narrower. There is a tendency to Moreover, the shape of the package is becoming larger.

[0014] For this reason, it has become difficult to evenly fill a large cavity with resin using the previous mold apparatus which was configured to pour resin only through a gate provided in the lower mold. As a result, the stage of the lead frame and the bonding wires are deformed, causing short circuits and disconnections from time to time.

[0015] Therefore, molds in which the upper mold is also provided with gates have come to be used, and resin is now poured into the cavity through the upper and lower gates.

[0016]

[Problem to be solved by the invention] Therefore, FIG. 4(B)
If gates are provided in the upper and lower molds as shown in
Since the lower gate 2b and the upper gate 1b overlap, the cross-sectional area of the chocolate break becomes thick. As a result, gatebreaking by hand, which has traditionally been done, has become troublesome.

FIG. 5 is an explanatory diagram of damage to a molded product due to gate break. In the figure, when both the upper gate 1b and the lower gate 2b are provided, when attempting to break the gate near the wall of the molded product 6, the molded product 6 may be chipped as shown in FIG. 5(A). , cracks may occur in the molded product 6 as shown in FIG. 5(B). In addition, in severe cases, there is a problem that a serious failure occurs, such as the internal leads of the lead frame 8 being exposed as shown in FIG. 5(C).

[0018] Therefore, the present invention provides a resin sealing metal which is formed by providing two constrictions in the gate and performing gate breaking in two steps to prevent damage to molded products such as semiconductor device packages. The purpose is to provide a mold device and a gate cutting method.

[0019]

[Means for Solving the Problem] The problem described above has an upper mold and a lower mold, the upper mold has an upper cavity and an upper gate connected to the upper cavity, and the upper gate has an upper mold. ,
It has a constricted portion close to the upper cavity,
The lower mold includes a lower cavity and a lower gate connected to the lower cavity, and the lower gate has a first constricted portion adjacent to the lower cavity and a second constricted portion opposite to the opposite side of the upper gate. When gate breaking a molded product resin-sealed by the mold device, first, the opposite side of the upper gate and the second constricted portion are are cut at opposite positions,
Next, the problem is solved by a gate cutting method configured to cut the gate at a position where the constricted portion and the first constricted portion face each other.

[0020]

[Function] In conventional mold equipment for resin encapsulation that molds semiconductor devices, etc., when the molded product becomes large and the cavity capacity increases, gates are provided not only on the lower mold but also on the upper mold. While the molded product has occasionally been chipped or cracked during gate breaking after molding, the present invention prevents such damage from occurring to the molded product.

That is, a constricted portion close to the upper cavity is formed in the upper gate of the upper mold. Further, a first constriction portion and a second constriction portion are formed at the lower gate of the lower mold. At a position where the constricted portion of the upper gate and the first constricted portion of the lower gate face each other, a so-called chocolate break is formed in which both constricted portions are respectively covered with resin. On the other hand, the second constriction is
A chocolate break is formed at one constriction covered with resin.

[0022] In this way, since the second constriction does not cover the opposite side of the upper gate with resin, the chocolate break of the second constriction is better than the constriction of the upper gate and the first side of the lower gate. It can be made easier to break than the chocolate break formed by the constricted part. This point is the gist of the technical matters of the present invention.

[0023] When gate-breaking the molded product, the molded product is first cut using the chocolate break at the second constriction. This cutting operation can be easily performed manually. Next, in the case of a semiconductor device, when a lead frame or the like is cut by machining, the cut is simultaneously made at a position where the constricted portion of the upper gate and the first constricted portion of the lower gate face each other.

[0024] In this way, during the first stage gate break, the cutting position is far from the wall of the molded product, and it is easy to break, so even if the molded product is cut somewhat roughly by hand, the molded product will not be damaged. It never happens.

[0025] Next, during the second stage of gate breaking for finishing the molded product, the cutting work can be performed carefully by machining or the like. Therefore, the molded product will not be damaged.

Thus, according to the resin sealing mold device and gate cutting method of the present invention, the shape of the molded product becomes large, and even if the mold device has a structure in which gates are provided in the upper and lower molds, , gate breaking can be performed without damaging the molded product.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram of an embodiment of the present invention, in which (A) is a plan view, (B) is a sectional view taken along line XX, and FIG. 2 is a perspective view of an example of a molded product. In the figure, 1 is the upper mold, 1a is the upper cavity, 1b is the upper gate, 1c is the opposite side, 2 is the lower mold,
2a is the lower cavity, 2b is the lower gate, 3 is the narrow part, 4
5 is a first constricted portion, 5 is a second constricted portion, 6 is a molded product, and 7 is a runner 8 is a lead frame.

In FIG. 1, the upper mold 1 has an upper cavity 1.
a, and an upper gate 1b connected to the upper cavity 1a. Further, the lower mold 2 is provided with a lower cavity 2a facing the upper cavity 1a, and a lower gate 2b continuous with the lower cavity 2a and facing the upper gate 1b. The lower gate 2b is connected to the runner 7.

On the other hand, the upper gate 1b is provided with a constricted portion 3 adjacent to the upper cavity 1a. On the other hand, the lower gate 2b is provided with a first constricted portion 4 close to the lower cavity 2a and a second constricted portion 5 facing the opposite side 1c of the upper gate 1b.

Taking an example of a semiconductor device, the molded product 6 molded by the mold apparatus of the present invention constructed in this way has a plurality of lower gates 2b lined up on the runner 7, as shown in FIG. The molded product 6 is taken out from the mold in a state where it is connected to each lower gate 2b and lead frame 8.

[0031]The upper gate 1b has an opposite side 1c,
A constricted portion 3 is formed close to the side wall of the molded product 6, and the lower gate 2b includes a first constricted portion 4 that is adjacent to the side wall of the molded product 6 and faces the constricted portion 3, and an opposite side 1c of the upper gate 1b. A second constricted portion 5 is formed opposite to.

By the way, the position where the constricted portion 3 and the first constricted portion 4 face each other is a chocolate break in which both the constricted portions 3 and 4 are covered with resin. On the other hand, at the position where the opposite side 1c and the second constricted portion 5 face each other, there is no resin on the opposite side 1c side of the upper gate 1b, and only the second constricted portion 5 forms a chocolate break.

In other words, the chocolate break at the second constriction 5 is more likely to break than the chocolate breaks at both constrictions 3 and 4. Therefore, by manually bending the molded product 6 connected to the runner 7 as shown in FIG. 4(B), the gate break can be easily made at the chocolate break position of the second constricted portion 5. .

Next, in the case of resin sealing of a semiconductor device, since each molded product 6 is connected by a lead frame 8, when cutting the lead frame 8 by machining or the like, both ends are cut at the same time. Cut parts 3 and 4.

[0035] Then, when breaking the gate, the gate can be cut without damaging the molded product 6 such as the package.

[0036]

[Effect of the invention] The mold equipment used in the process of resin-sealing molded products such as semiconductor device packages has an upper gate on the upper mold in order to improve the circulation of the resin when the shape of the molded product becomes large. Since the gate is difficult to break, the molded product is often damaged when the gate is broken. In contrast, according to the present invention, two chocolate breaks are provided at the two constricted portions provided on the lower gate. Then, when separating the runners, etc., cut with a chocolate break that is easy to break and does not affect the molded product, and when shaping the molded product by machining, etc., cut the chocolate break near the wall of the molded product.

[0037] In this way, no damage such as chipping or cracking is caused to the molded product during gate breaking, and the present invention greatly contributes particularly to streamlining the manufacturing process of resin-sealed semiconductor devices.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, in which (A) is a plan view and (B) is a XX sectional view.

FIG. 2 is a perspective view of an example of a molded product.

FIG. 3 is a perspective view of essential parts of an example of a conventional mold device for resin sealing.

4 is an enlarged view of the Y section in FIG. 3, (A) is an enlarged perspective view, and (B) is an enlarged sectional view taken along Z-Z.

FIG. 5 is an explanatory diagram of damage to a molded product due to gate break.

[Explanation of symbols]

1 Upper mold 1a
Upper cavity 1b Upper gate 1c Opposite side 2 Lower mold 2a
Lower cavity 2b Lower gate 3 Constriction 4 First constriction 5 Second constriction 6 Molded product 7 Runner 8 Lead frame

Claims (2)

[Claims] Claim 1: The upper mold (1) has an upper mold (1) and a lower mold (2), and the upper mold (1) has an upper cavity (1a) and an upper gate (1b) connected to the upper cavity (1a). Ingredients,
The upper gate (1b) has a constricted portion (3) close to the upper cavity (1a), and the lower mold (1b) has a constricted portion (3) close to the upper cavity (1a).
2) consists of a lower cavity (2a) and a lower cavity (2a);
2a), and the lower gate (2b) has a first constriction (4) adjacent to the lower cavity (2a) and an opposite side (1) of the upper gate (1b).
A mold device for resin sealing, characterized in that it has a second constricted portion (5) opposite to c). 2. When gate breaking a molded product (6) resin-sealed by the mold apparatus according to claim 1, first, the opposite side (1c) of the upper gate (1b) and the second constricted portion ( 5) A method for cutting a gate, characterized in that the gates are cut at positions where the constricted portions (3) and the first constricted portion (4) face each other.