WO2013079011A1

WO2013079011A1 - Lead frame for encapsulating integrated circuit and corresponding encapsulation device

Info

Publication number: WO2013079011A1
Application number: PCT/CN2012/085609
Authority: WO
Inventors: 郑志荣; 孙宏伟; 卫安琪; 王伦波
Original assignee: 无锡华润安盛科技有限公司
Priority date: 2011-12-02
Filing date: 2012-11-30
Publication date: 2013-06-06
Also published as: CN103137593A

Abstract

A lead frame (3) for encapsulating an integrated circuit, including an island (30), several pins (300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 3010, 3011, 3012, 3013, 3014, 3015) around the island (30), and a connection rib (32) extending from the island (30). It is characterized in that two pins (307, 308) out of the several pins (300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 3010, 3011, 3012, 3013, 3014, 3015) are provided thereon with a widening portion (3071, 3081), and the end portion of the connection rib (32) forms a fork structure. The lead frame can be applied to encapsulate a chip and a crystal oscillator into a capsule.

Description

Description Leadframe for integrated circuit package and corresponding packaged device

The present invention relates to chip packaging technology, and more particularly to a technique for packaging a chip and a crystal oscillator in a package.

Background technique

The pursuit of light and small electronic devices has led to higher demands on the modularity or integration of devices. In addition to continuously improving the chip packaging process to make the packaged device thinner and smaller, it is one of the means to achieve the above purpose by packaging more devices in a plastic package according to the circuit function, and packaging the chip and the crystal oscillator. It is an example in a plastic body.

In a conventional integrated circuit, only one or more chips are packaged in a plastic package, and the chip and the crystal oscillator are rarely packaged together. This is mainly because the crystal oscillator occupies a large volume in the package, and the conventional lead frame cannot meet the demand. Figure 1 is a schematic illustration of a conventional small outline package (S O P ) lead frame with 8 pins. As shown, the leadframe includes islands 120, eight inner leads 111-118 disposed about the islands, wherein the islands 120 are formed by a recessing process. If the volume of the crystal oscillator is not taken into consideration, it is still problematic to package the chip and the crystal oscillator together with the lead frame shown in Fig. 1, which will now be described in conjunction with Fig. 2. Fig. 2 is a schematic cross-sectional view showing the state in which a crystal frame and a chip are simultaneously packaged by using the lead frame shown in Fig. 1. As shown, the semiconductor chip 40 is placed below the island 120, and the crystal 50 is placed above the island 120. Lead wire 60 is formed by bonding wire between chip 40 and pin 110. In this configuration, the middle portion of the lead 60 is easily contacted with the edge 1201 of the island 120, resulting in a short circuit failure or other reliability problems. Due to the large difference in height between the pin 110 and the chip 40, the problem of the middle of the lead contacting the edge of the island is more likely to occur when the lateral width of the island 120 is wider.

Chinese patent CN200920286409.9 discloses a lead frame which can encapsulate the chip 40 and the crystal oscillator 50 in a plastic body and can avoid the above problems. Summary of the invention

In view of the above, the present invention provides a lead frame for an integrated circuit package, comprising: an island, a plurality of leads surrounding the island, and a connecting rib extending from the island, wherein On two of the plurality of pins, a widening portion is provided, and the ends of the connecting ribs form a bifurcated structure.

Preferably, the lead frame is used for simultaneously packaging a chip and a crystal oscillator, a first surface of the island is used for setting a chip, and a second surface opposite to the first surface is used for setting a crystal oscillator, the chip and the All or a portion of the pins are bonded, and the crystal is bonded to two pins provided with the widened portion.

The present invention also provides an array of leadframes for an integrated circuit package, the array being comprised of a plurality of leadframes including islands, a plurality of leads surrounding the island, and from the island An extended connecting rib, wherein a widened portion is disposed on two of the plurality of pins, and an end of the connecting rib forms a bifurcated structure.

Preferably, a plurality of circular grooves are formed on the cutting line of the connecting rib.

The present invention also provides a package device comprising a lead frame, a chip, a crystal oscillator, and a package matched with the lead frame, wherein the lead frame includes an island, a plurality of surrounding around the island a pin, and a connecting rib extending from the island, on two of the plurality of pins, a widening portion is provided, and an end of the connecting rib forms a bifurcated structure, the chip Located on a first surface of the island, the crystal is disposed on a second surface opposite the first surface of the island. Preferably, the chip is bonded to all or part of the plurality of pins, and the crystal oscillator is bonded to two pins provided with the widened portion.

The lead frame of the present invention can simultaneously solder a crystal oscillator and a chip. In addition, since at least the portion where the crystal oscillator is bonded to the pin bonded to the crystal is widened, the reliability of the crystal welding is ensured. DRAWINGS

Figure 1 shows the structure of a conventional small outline package (SOP) leadframe with 8 pins.

Fig. 2 is a schematic cross-sectional view showing a state in which a crystal frame and a chip are simultaneously packaged by using the lead frame shown in Fig. 1.

3 is a schematic diagram of a lead frame of an integrated circuit package structure in accordance with an exemplary embodiment of the present invention.

4 is a partial schematic view of the lead frame shown in FIG. 3 including inner pins 307 and 308 and a portion A of the second end portion 321 of the connecting rib.

Fig. 5 is a schematic view showing the arrangement of a crystal oscillator and a chip on the lead frame shown in Fig. 3, in which the chip is not shown.

Figure 6 is a schematic illustration of an array of leadframes formed from leadframes in accordance with the present invention.

detailed description

The invention will be further elucidated below in conjunction with the drawings. The drawings are merely schematic and are not intended to limit the specific shapes and sizes of the various components.

First, although the following description will be made by taking a lead frame of a planar frame structure as an example, it is not limited thereto. In practical applications, the invention is also applicable to non-planar frame structures. Here, the term "planar frame structure" refers to a small island, an inner lead, and a lead frame structure in which the connecting ribs are in the same plane.

3 is a schematic diagram of a leadframe for an integrated circuit package in accordance with an exemplary embodiment of the present invention. The lead frame 3 includes an island 30, a plurality of inner leads disposed around the island 30, and a connecting rib 32. In this example, leadframe 3 includes 16 internal pins, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 3010, 3011, 3012, 3013, 3014, and 3015, respectively. In actual applications, the number of internal pins is not limited to this, and it can be 8 or 24, etc. The portions of the connecting ribs 32 on both sides of the island 30 are a first end 320 and a second end 321 respectively. According to this embodiment, the first end 320 and the second end 321 are respectively extended from the small island 30 and form a bifurcated structure at a distance from the small island 30, and the bifurcated structure may be, for example, a herringbone structure.

According to the present invention, the inner lead for bonding the crystal oscillator is disposed at least wide to the portion for bonding the chip to ensure a more unnecessary amount for subsequent crystal welding. In this embodiment, exemplarily, the crystal oscillator is bonded with pins 307 and 308, and the extension portion 3071 extends from the pin 307, and the extension portion 3081 extends from the pin 308, so that the pins 307 and 308 are bonded to the crystal oscillator. Partially widened.

As shown in FIG. 3, when the chip and the crystal oscillator are mounted to different surfaces of the island and then subjected to a molding process, the molding compound may be removed from the first opening 320a and the second opening of the herringbone structure of the first end portion 320 of the connecting rib. 320b is poured into and/or poured from the first opening 321a and the second opening 321b of the chevron structure of the second end portion 321 of the connecting rib.

After the molding process, the packaged chips can be cut along the rib line 34. In an exemplary embodiment, a plurality of small circular grooves 400 may be provided along the plastic body cut line 34 (ie, the torn portion when the connecting rib is cut on the outer portion of the plastic seal) to weaken or avoid subsequent disconnection Damage to the resin body (i.e., the molded body) formed by the plastic when the rib is formed. In this example, a small circular groove can be formed in the connecting rib 32 along the rib line 34, and a small circular groove can be formed on the inner pins 307 and 308 along the rib line 34 at the same time, thus forming a plurality of small circular grooves 400.

4 is a partial schematic view of the lead frame shown in FIG. 3 including inner pins 307 and 308 and a portion A of the second end portion 321 of the connecting rib. As can be seen from Fig. 4, in this example, small circular grooves 4001, 4002, 4003, and 4004 are provided on the connecting ribs 32 along the rib line 34, and at the same time, the small ribs 34 are provided along the rib line 34 on the inner pins 307 and 308. Round grooves 4005 and 4006.

Fig. 5 is a schematic view showing the arrangement of a crystal oscillator and a chip on the lead frame shown in Fig. 3, in which the chip is not shown. A chip is disposed on the first surface (not shown) of the lead frame 3, and the second surface 36 is provided with a crystal. In this example, the first surface of the island refers to the face opposite to the second surface. In the present embodiment, the chip is placed in close contact with the first surface of the island 30 and bonded to the inner lead of the lead frame by a key alloy wire (not shown). It should be noted that the number of internal pins bonded to the chip depends on the chip. Although the lead frame 3 has 16 internal pins, not all of the 16 internal pins need to be bonded to the chip. In this example, the chip is bonded to the inner leads 301, 302, 303, 304, 307, 308, 309, 310, 313, and 314 by a key alloy wire.

After the chip is placed in close contact with the first surface of the island, the crystal oscillator 46 is placed on the second surface 36 of the island. Specifically, the two pins of the crystal are bonded to the inner leads 307 and 308 through bond alloy wires 467 and 468, respectively. According to this embodiment, the key Alloy wires 468 and 469 respectively bond extensions 3071 and 3081 from which inner pins 307 and 308 extend.

As described above, after the plastic molding is completed, the connecting ribs can be cut along the rib line 34, i.e., along the rib line 34. Since a plurality of small circular grooves 400 are provided at the joint root of the molded body, the resin formed by the plastic seal can be prevented from being damaged when the connecting rib is cut.

After the plastic seal is completed and the rib is cut, it is deformed into a packaged device including a chip and a crystal.

In the above description with reference to the accompanying drawings, a lead frame is taken as an example, but in the packaging process, a plurality of the above lead frames may be arranged to form an array of lead frames, as shown in FIG. 6 according to the present invention. Schematic diagram of an array of leadframes formed by leadframes.

The lead frame of the present invention can be made of A42 iron-nickel alloy and copper plated on the surface of the alloy, so that it is not necessary to plate silver in the portion where the crystal is required to be welded, thereby reducing the cost of the frame.

In summary, the lead frame of the present invention has a bifurcated structure at the end of the connecting rib, so that when the lower molding body is molded, the molding material is respectively connected to the two inlets 320 and 321 at both ends of the rib (ie, the first The first opening 320a and the second opening 320b of the end portion 320 and the first port 321a and the second port 321b of the second end portion 321 enter, thereby alleviating the pressure generated during the injection of the molding compound, and avoiding the pressure. Too large an impact on the bond alloy wire of the chip causes it to break, causing an open circuit or contact with an adjacent gold wire to cause a short circuit. In the lead frame of the present invention, the pin bonded to the crystal oscillator, at least the portion to which the crystal oscillator is bonded, is widened, thereby ensuring the reliability of the crystal welding. In addition, in the manufacturing process of the lead frame of the present invention, a small circular groove is selectively provided on the plastic-cutting rib line (sometimes referred to as a molding outline) of the cutting rib, thereby cutting off The connecting ribs become easier and do not damage the molded body when cut.

Although the present invention has been described in detail with reference to the preferred embodiments thereof, it will be understood by those of ordinary skill in the art that Within the scope of the program.

Claims

Claim

A lead frame for an integrated circuit package, comprising: an island, a plurality of pins surrounding the island, and a connecting rib extending from the island, wherein in the plurality of pins The two pins are provided with a widening portion, and the ends of the connecting ribs form a bifurcated structure.

2 . The lead frame according to claim 1 , wherein the lead frame is used for simultaneously packaging a chip and a crystal, and the first surface of the island is configured to set a chip, and the first surface is opposite to the first surface The two surfaces are used to set a crystal oscillator, and the chip is bonded to all or a part of the plurality of pins, and the crystal oscillator is bonded to two pins provided with the widened portion.

The lead frame according to claim 1 or 2, wherein a plurality of circular grooves are formed in the cut line of the connecting rib.

4. A lead frame array for an integrated circuit package, wherein the array is comprised of a plurality of lead frames, the lead frame including islands, a plurality of pins surrounding the island, and The connecting rib extending from the island, on two of the plurality of pins, is provided with a widening portion, and the end of the connecting rib forms a bifurcated structure.

The lead frame array according to claim 4, wherein the lead frame is used for simultaneously packaging a chip and a crystal, and the first surface of the island is used for setting a chip, and the first surface is opposite to the first surface The two surfaces are used to set a crystal oscillator, and the chip is bonded to all or a part of the plurality of pins, and the crystal oscillator is bonded to two pins provided with the widened portion.

The lead frame array according to claim 4 or 5, wherein a plurality of circular grooves are formed in the cut line of the connecting rib.

A package device, comprising: a lead frame, a chip, a crystal oscillator, and a package matching the lead frame, wherein the lead frame includes an island and surrounds the island a plurality of pins, and a connecting rib extending from the island, on two of the plurality of pins, a widening portion is provided, and an end portion of the connecting rib forms a bifurcation structure The chip is disposed on a first surface of the island, and the crystal is disposed on a second surface opposite the first surface of the island.

The package device according to claim 7, wherein the chip is bonded to all or part of the plurality of pins, and the crystal oscillator is provided with the widened portion. Two pin bonds.