TWI536524B - Semiconductor device for restraining creep-age phenomenon and fabricating method thereof - Google Patents

Description

Semiconductor device for suppressing creepage phenomenon and preparation method thereof

The present invention generally relates to a semiconductor device, and more particularly to a power semiconductor device for optimizing electrical clearance and increasing creep creepage distance and a method of fabricating the same for use in a semiconductor device A better electrical safety distance is obtained between the terminals.

In a conventional power semiconductor device, a large current or a high voltage is usually applied between the respective pins, and with the development of mainstream technology, it is often necessary to sufficiently reduce the size of the device to meet the requirements of lightness, and the corresponding negative effects. Yes, the insulating material around the pins that are very close to each other is easily polarized, causing the insulating material to be charged, affecting the normal operation of the device, and serious conditions may cause safety hazards, especially in wet or dusty In harsh environments, the phenomenon of creepage is becoming more and more serious. In North American electrical product safety standards, ANSI/UL standards are commonly used for evaluation. Electrical safety distance is an important structural review link for electrical product safety standards. Based on the consideration of the suppression of creepage, the control of parameters such as clearance or creepage distance is particularly important.

Figure 1A shows a conventional TO-220 device in which the metal mounting base of the power device for supporting the power MOSFET wafer is completely sealed within the molding body 10, Pins 11~13 and heat sink 14 are exposed outside the package body 10. The pins 11, 13 are generally independent and disconnected from the metal mounting base as the gate first and source contact terminals, respectively. Pin 12 is usually connected to the pedestal as a drain terminal, and pins 11 to 13 are arranged in parallel at equal distances. The problem is that the pins 11~13 are too close to each other, causing the creepage distance between them to be different and the requirements under high voltage conditions, such as the symmetrical centerline of the pin 12 along the length direction and the pin 11 or 13 The distance between the symmetrical centerlines along the length direction is substantially 2.54 mm, and the narrowest distance between the portion of the lead 12 closest to the molded body and the portion of the lead 11 (or 13) closest to the molded body is only About 1.27mm, such a pin distance is easy to induce creepage. In order to overcome this problem, U.S. Patent No. 6,255,722 B1 proposes a scheme in which, as shown in Fig. 1B, a thin portion is formed on the side of the molding body 60 between the intermediate pin 24 and the two pins 23, 25 on both sides thereof. In the slots 70 and 71, although the physical spacing between any two of the pins 23 to 25 does not change significantly, the slot 70 is equivalent to pulling the creepage distance between the pins 23 and 24, and the slot 71 is equivalent to pulling. The creepage distance between pins 24, 25 is turned on. In other documents which increase the creepage distance, for example, U.S. Patent Application No. 6,921,262 B1, not only is the molded body 50 formed in the side wall between the two pins 38 (as in the top view of FIG. 1C-1), but also in the middle. One pin 44 and the two side pins 38 are respectively disposed on different planes (such as the side view of FIG. 1C-2), and the creepage distance can also be adjusted.

The methods referred to in the above literature have very limited effects on changing the creepage distance, especially when a high voltage is applied to the drain or source pin, and the creepage phenomenon in a harsh environment cannot be suppressed at all. The present invention is based on this point, and more effectively raises the creepage distance to suppress this negative effect.

In a power semiconductor device provided by the present invention, a wafer mounting unit having a pedestal and a plurality of pins is disposed, and a plurality of pins arranged side by side are located near one side edge of the pedestal, among the plurality of pins The first pin is connected to the base and the second and third pins are disconnected from the base, and the second and third pins each have a bonding area near one end of the base, and the second pin is adjacent to the first and a third pin and the first, second and third pins are arranged in a non-equidistant arrangement; a wafer attached to the susceptor, the first electrode disposed on the back surface of the wafer is electrically connected to the pedestal via a conductive material The second and third electrodes disposed on the front surface of the wafer opposite to the back surface are respectively electrically connected to the respective bonding regions of the second and third pins through the conductive structure; the susceptor, the wafer, the conductive structure, and The sealing portion of the second and third pins is covered by a molding body, and the molding body includes a plastic extending portion extending along a length direction of one of the first, second and third pins.

In the above power semiconductor device, the distance between the third pin and the second pin may be set closer than between the first pin and the second pin.

In the above power semiconductor device, a side edge of the second pin adjacent to the third pin extends in parallel with a side edge of the third pin adjacent to the second pin, and the side edge of the second pin is along the second side The length of the pin extends from the inside of the molded body to the outside of the molded body.

In the above power semiconductor device, the plastic package extension extends along the length direction of the second and third leads.

In the above power semiconductor device, the side edge of the second pin adjacent to the first pin includes a corner portion adjacent to the first pin and the pedestal.

In the above power semiconductor device, the distance between the first pin and the second pin is set closer than the third pin to the second pin.

The above power semiconductor device, a side of the second pin adjacent to the first pin The edge extends parallel to a side edge of the first pin adjacent to the second pin, and the side edge of the second pin extends from the inside of the molding body to the outside of the molding body along the length of the second pin.

In the above power semiconductor device, the plastic package extension extends along the longitudinal direction of the first and second leads.

In the above power semiconductor device, a side edge of the second pin adjacent to the third pin includes a corner portion toward the third pin and toward the pedestal.

In the above power semiconductor device, the wafer is a MOSFET or an IGBT, the first electrode is a drain, and the second and third electrodes on the front side of the wafer include a source and a gate.

In a packaging method of a power semiconductor device provided by the present invention, the method includes the steps of: providing a lead frame having a plurality of wafer mounting units, the wafer mounting unit having a base and a plurality of pins, and a plurality of pins arranged side by side Located near one side edge of the pedestal, the first pin of the plurality of pins is connected to the pedestal and the second and third pins are disconnected from the pedestal, and the second and third pins are respectively adjacent to the pedestal end. a bonding area is provided, wherein the second pin is adjacent to the first and third pins, and the first, second and third pins are arranged in a non-equidistant manner; the wafer is adhered to the base, so that The first electrode disposed on the back surface of the wafer is electrically connected to the pedestal through the conductive material; the conductive structure is used to electrically connect the plurality of electrodes on the front side of the wafer one to one to the respective bases of the plurality of pins disconnected from the pedestal a bonding body; forming a molding body, covering a pedestal, a wafer, a conductive structure, and a bonding region of each pin disconnected from the pedestal, the molding body including at least one along the first, Long-length plastic extension of one of the second and third pins Extension portion; cutting the lead frame, each of the wafer mounting unit detached.

In the above method, the third pin is set closer to the second pin than the first pin.

In the above method, a second pin is adjacent to the third pin of the side edge and the third pin A side edge adjacent to the second pin extends in parallel and extends from the inside of the molding body to the outside of the molding body along the length of the second pin.

In the above method, the plastic extension extends along the length of the second and third pins.

In the above method, the side edge of the second pin adjacent to the first pin includes a corner portion toward the first pin and toward the pedestal.

In the above method, the first pin is closer to the second pin than the third pin.

In the above method, a side edge of the second pin adjacent to the first pin extends parallel to a side edge of the first pin adjacent to the second pin, and extends from the inside of the molding body along the length of the second pin to The outside of the plastic body.

In the above method, the plastic extension extends along the length of the first and second leads.

The above method, wherein the second pin is adjacent to a side edge of the third pin and includes a corner portion toward the third pin and toward the base.

In the above method, the wafer is a MOSFET or an IGBT, the first electrode is a drain, and the second and third electrodes disposed on the front surface of the wafer include a source and a gate.

These and other advantages of the present invention will no doubt become apparent to those skilled in the <RTIgt;

10‧‧‧Plastic body, package

11, 12, 13, 23, 24, 25, 38, 44, 113, 114, 115‧‧‧ pins

14, 112, 112'‧‧ ‧ heat sink

50, 60, 140‧‧ ‧ plastic enclosure

70, 71‧‧‧ fine grooves

100‧‧‧ lead frame

110‧‧‧ wafer mounting unit

111‧‧‧Base

111a‧‧‧ edge

120‧‧‧ wafer

120a, 120b‧‧‧ reinforced

121‧‧‧Gate

122‧‧‧ source

130‧‧‧Leader

135‧‧‧Electrical materials

141, 141', 142‧‧ ‧ plastic extension

1130, 1140‧‧‧ bonding area

1131, 1141, 1151‧‧‧ shoulder

1131a, 1141a‧‧ corner

1132, 1142, 1152‧‧‧ pin end

L‧‧‧ length value

W‧‧‧ distance value

Embodiments of the present invention are described more fully with reference to the accompanying drawings. However, the attached drawings are for illustration and illustration only and are not intended to limit the scope of the invention.

Figure 1A shows the typical TO-220 series package.

FIG. 1B is a scheme for increasing the creepage distance disclosed in US Pat. No. 6,255,722 B1.

Figures 1C-1 through 1C-2 illustrate a scheme for increasing creepage distance as disclosed in U.S. Patent Application No. 6,921,262 B1.

Fig. 2 is a plan view of the lead frame of the present invention.

3A to 3B are views showing the structure of a wafer mounting unit included in the lead frame.

Figures 4A through 4C-3 are process flows for preparing the apparatus of the present invention.

5A to 5B are an embodiment proposed based on the flow of Figs. 4A to 4C-3.

6A to 6B are another embodiment proposed based on the flow of Figs. 4A to 4C-3.

7A to 7B are schematic views of adjusting the effective creepage distance.

8A to 8B are schematic views showing the structure in which the bottom surface of the susceptor is exposed from the molded body.

9A to 9D are schematic views showing the flow of the bottom surface of the base and the entire heat sink from the molded body.

10A through 10D are embodiments in which a pin that is not connected to the susceptor is moved to a pin that is connected to the susceptor.

Figure 2 shows a portion of a lead frame 100 of a metal material. We will now follow the industry standard TO single in-line package series as an example. The lead frame 100 typically includes a plurality of wafer mounting units 110. , as shown in the enlarged view of Figure 3A. Each of the wafer mounting units 110 includes at least one substantially square metal mounting base 111 for carrying and adhering the wafer, or a base island, and one edge 111a of the opposite pair of side edges of the base 111. Nearby, set multiple parallel arranged pins 113, 114, 115 or some A greater number of unillustrated pins, wherein pins 113, 114 are disconnected from pedestal 110, and pin 115 is coupled to pedestal 110, which is disposed intermediate pins 113 and 115. In a pair of side edges of the base 111, a fork-shaped fin 112 is connected to the other edge opposite to the edge 111a, and a slit is provided between the fingers of the fin 112, the opening direction of which faces away from the base In the manner of 111, the inner portion of the slit relative to the portion at the opening thereof is arcuate, or close to a semicircle, which can be used for positioning of the lead frame 100. Note that the heat sink 112 described herein is only in a plurality of selection modes. One should not be used as a limitation.

In the embodiment of FIG. 3A, each of the plurality of pins 113, 114, 115 respectively has a shoulder 1131, 1141, 1151 having a strip-like flat structure. The outer end of the shoulder 1131 of the pin 113 integrally extends a pin end portion 1132 which is also in the form of a strip-like flat plate. The bonding region 1130 of the pin 113 is disposed at the opposite inner end of the base portion 113. Similarly, the outer end of the shoulder 1141 of the pin 1141 integrally extends out of a pin end portion 1142 having a strip-like flat structure, and the bonding portion 1140 of the pin 113 is disposed at the other inner end of the base portion 1141. The outer end of the shoulder 1151 of the pin 115 integrally extends a pin end portion 1152 of a strip-like flat structure, and the other inner end of the shoulder 1151 is connected to an edge 111a of the base 111 and is connected to the edge. 111a is adjacent to either end of the two sides (or both corners), and substantially the pedestal 111 and the fins 112 and the leads 115 are integrally formed integral structures. The lengths of the shoulders 1131 to 1151 and the lead ends 1132 to 1152 extend in a direction perpendicular to the length of the edge 111a. Wherein, the respective bonding regions 1130 and 1140 of the mutually adjacent pins 113, 114 which are disconnected from the susceptor 111 are respectively used for receiving the bonding of a lead, a metal piece, a metal strip or other conductive structure for connecting the wafer. Electrode terminals, and the elongated bonding regions 1130, 1140 are all extended along the length direction of the edge 111a so as to increase the area of the bonding region to a certain extent, so that it can be placed thereon Bonding connects a larger number of leads. In an optional embodiment of the present invention, the pin 115 connected to the susceptor 111 is not interposed between the pins 113 and 114 disconnected from the susceptor 111, and the pins 113 and 114 are disposed around the pin 115. Either of the two sides, that is, on the same side of the pin 115.

In some circuits, the drain of the N-channel MOSFET needs to be connected to a high voltage, where the high voltage is relative to the low potential on the source or gate, such as the bottom drain of the vertical N-MOSFET. Connecting to the pedestal 111 corresponds to the high potential of the pin 115 connected to the drain. Maximizing the proximity of the adjacent pins 113, 114 to each other to shorten the distance between them, thereby forming a designated one of the plurality of pins 113-115, such that the set of pins, for example, the pin 113, The spacing between 114 is less than the spacing between any one of the set of pins 113 or 114 to the remaining one of the pins 115, such that the pins 113-115 appear as non-equidistant arrangements. One of the pin groups 113, 114 is connected to the source, and increasing the distance between the pin group 113, 114 and the pin 115 can pull the distance between the open source and the drain, which is to improve the creepage distance. Useful, will be described in detail in the follow-up content.

In FIG. 3A, the inner pin 114 is adjacent to the outer pin 113 that is disconnected from the susceptor 111, away from the pin 115 connected to the susceptor 111, and it is assumed that the pin 114 can be placed closest to the pin 113. The extreme limit, which is dependent on the process accuracy of the die cutting equipment or etching equipment used to make the lead frame. In Fig. 3A, a flange or a corner 1131a is provided on a side edge of the shoulder 1131 facing away from the pin 114, and a corner 1141a is provided on a side edge of the shoulder 1141 facing away from the pin 113. The corner 1141a can be Move closer to pin 115 and close to pedestal 111. Further, a corner portion may be provided on both side edges of the base portion 1151 or a corner portion (not shown) may be provided on any one of the side edges. The role of the corners is to strengthen the mechanical strength of the pins, especially the shoulders, from deformation.

However, the corners are not necessary. For example, when the corners are removed, the widths of the shoulders 1131, 1141, and 1151 are equal to the widths of the lead ends 1132, 1142, and 1152, respectively. In this embodiment, an end face adjacent to the pin 114 is flush with the side edge of the shoulder 1131 near the pin 114 while being flush with the pin end 1132 near a side edge of the pin 114. And an end face of the bonding region 1140 near the pin 113 is flush with the side edge of the shoulder 1141 near the pin 113 while being flush with the pin end 1142 near a side edge of the pin 113. One result is that one edge of the adjacent pin 113 of the pin 114 is substantially parallel to one edge of the adjacent pin 114 of the pin 113 and extends from the interior of the subsequently formed molding body along the length of the pin 114 to The exterior of the molded body. The illustrated structure minimizes the distance between pin 113 and pin 114, that is, the distance between pin 114 and pin 115 is maximized. In addition, although not shown in the drawings, it should be understood that a corner portion may be provided on each of the side edges of the shoulder portions 1131 to 1151, or a corner portion may be provided on any one of the side edges, and the bonding region 1130 The extent of the extension of 1140 along the edge 111a is not limited by the illustration. The end faces of the two ends of the bonding region 1130 may be correspondingly protruded from the side edges of the shoulders 1131, and the end faces of the bonding regions 1140 may be The side edges protruding from both sides of the shoulder 1141 can also be flush with it. 3B is a vertical cross-sectional view of the susceptor 110 along the dashed line AA of FIG. 2, the leads 113, 114, 115 are coplanar, the pedestal 111 and the heat sink 112 are coplanar, but the leads 113-115 and the pedestal 111 are located in two staggered planes. 4A to 4C-3 illustrate a method of preparing a semiconductor device capable of suppressing creepage. In order to hold the wafer mounting units 110 in the lead frame 100, they are prevented from undergoing a large deformation in the transportation or process steps, and some of the ribs are provided to provide physical support. The free ends of the pin ends 1132 to 1152 of the respective pins 113 to 115 of each of the wafer mounting units 110 are connected to one of the ribs 120b of the lead frame 100, and the pin ends 1132 to 1152 are on the lead frame. After cutting it, It can be inserted into the receiving hole of the socket mounted on the PCB, which can also be called the plug portion of the pin. The other rib 120a of the lead frame 100 is also connected to the pin end 1132 (or 1142, 1152) of each pin 113 (or 114, 115), and the rib 120a is connected to the pin end 1132 (or 1142). , 1152) near the other end of the shoulder 1131 (or 1141, 1151) of its associated pin, where the other end is relative to the free end of the pin end 1132 ~ 1152. The spaced apart ribs 120a, 120b are arranged in parallel.

In Fig. 4A, the step of performing a patch is performed by using a conductive adhesive material to adhere a plurality of power MOSFET wafers 120 one by one to a plurality of susceptors 111, and the bottom drain of the bottom surface of the wafer 120 is bonded. The material is electrically connected to the base 111. Then, the wire bonding process is performed to electrically connect the gate electrode 121 on the front surface of the wafer 120 to the bonding region 1130 of the pin 113 through the wire 130, and electrically connect the source electrode 122 on the front surface of the wafer 120 to the lead wire 130 through the plurality of leads 130. On the bonding area 1140 of the foot 114, the lead 130 herein may be replaced by a similar conductive structure such as a metal piece or a strip-shaped metal conduction band. Note that the electrode positions on the front side of the wafer 120 can be interchanged. In other words, the gate electrode 121 can also be electrically connected to the bonding region 1140, and the source electrode 122 can also be electrically connected to the bonding region 1130. As shown in FIG. 4B, a molding process is performed, and a molding material 140 is formed by using a molding material such as an epoxy resin to mold the wafer mounting unit 110, the wafer 120, and the leads 130, and the molding body 140 is wafer-to-wafer. The mounting unit 110 is coated in such a manner that at least the susceptor 111 and the bonding regions 1130 and 1140 are covered. At the same time as the molding body 140 is formed, a plastic molding extension portion 141 is formed integrally formed with the molding body 140, and the plastic molding extension portion 141 is used to mold a part or all of the shoulder portion 1151. The shoulders 1141~1151 are not covered by any plastic extensions. In the 4C-1 diagram, the cutting step of the lead frame is performed, mainly by punching the continuous ribs 120a, 120b to cut and separate the respective pins (113 or 114, 115) from the ribs. Each of the wafer mounting units 110 is separated from the lead frame 100. Generally, after the plastic molding is completed, it is often necessary to plate a metal layer for protecting or enhancing electrical contact on the surface of the portion of the lead 113-115 extending to the outside of the molding body 140, and finally the pin end portions 1132 to 1152 are The ribs are cut and opened, and the semiconductor device shown in Fig. 4C-3 is separated. Note that some of the detailed standard packaging processes that are well known in the industry are not described in the present invention.

4C-2 is still a cross-sectional view of the broken line AA in Fig. 2, except that the plastic sealing has been completed at this time, in which the wafer 120 is adhered to the top of the susceptor 111 by a conductive material 135 such as solder paste or conductive silver paste. On the surface, the molding body 140 completely encapsulates the susceptor 111 and the heat sink 112 and the wafer 120 without being exposed, and the respective bonding regions 1130 and 1140 of the leads 113 and 114 are also sealed in the molding body 140. . The illustrated plastic extension 141 is generally tapered, thinner than the molded body 140, extending outwardly from a side wall of the molded body 140 and adjacent to the pins. We set the length value of the plastic extension portion 141 to extend outward in the longitudinal direction of the base portion 1151. Referring to the top view of FIG. 3A and the perspective view of FIG. 4C-3, if the narrowest portion between the base portion 1141 and the base portion 1151 is set The distance value is about W, and the effective creepage distance at this time in the present invention is roughly the sum of both L and W. In a non-limiting example, if the semiconductor device of FIG. 4C-3 is the same as the overall size of the device of FIG. 1A, generally L can be 2 to 4 mm, and W can be 2 to 4 mm, so 4C- The creepage distance of Fig. 3 is about 4 mm, but the creepage distance in Fig. 1A is only about 1.27 mm. It can be seen that the contribution of the present invention to increasing the creepage distance is appreciated by those skilled in the art. See what it is.

The embodiment of FIGS. 5A to 5B is based on the flow of FIG. 4A to FIG. 4C-1, similar to FIG. 4B and FIG. 4C-3, the biggest difference is that there is no plastic pin 115 in the molding process. The shoulder 1151 is not prepared with the plastic extension 141, but in the same way, Another different plastic extension 142 of the molded body 140 is formed, the plastic extension 142 extending along the length of the lead 113 (or 114, 115). The plurality of pins 113, 114 disconnected from the pedestal are adjacent to each other and away from the pins 115 connected to the pedestal 111. In this case, the plastic extension 142 is used to cover the respective sets of pins 113, 114. The base portions 1131, 1141 and the plastic seal extension portion 142 are wrapped in such a manner that the base portions 1131, 1141 can be entirely covered or only a part of each of the base portions 1131, 1141 can be covered. Generally, the plastic seal extension portion 142 is only one plastic seal. The plastic extension 141 of the base 115 is slightly wider and occupies a larger volume. Note that the base 1151 is not covered by any plastic extension at this time.

The embodiments of FIGS. 6A to 6B are based on the processes of FIGS. 4A to 4C-1, similar to 4B and 4C-3, and the biggest difference is that not only the sealing portion 141 is molded by the sealing portion 141 in the molding process. The shoulder 1151 of the foot 115, but in the same manner, another different plastic extension 142 of the molding body 140 is additionally prepared, and the shoulders 1131, 1141 of the set of pins 113, 114 are molded together. The plastic extension portions 141, 142 coexist at the same time. If the length of the plastic extension portion 142 extending along the longitudinal direction of the lead 113 is also L, the actual creepage distance in FIG. 6B is increased by about L with respect to the fifth FIG. , about 2L plus W.

7A to 7B are similar to FIG. 4B and FIG. 4C-1, although the plastic extension portion 141' is additionally prepared, but the plastic extension portion 141' covering the shoulder portion 1151 extends along the length direction of the base portion 1151. The length value is smaller than that of FIG. 4B, which is equivalent to only a shorter portion of the shoulder 1151 near the edge 111a being wrapped within the plastic extension 141', and the shoulder 1151 being closer to the longer end of the pin end 1152. A portion is exposed outside of the plastic extension 141'. Or a shorter portion of the shoulders 1131, 1141 near the bonding regions 1130, 1140 is wrapped in another plastic extension, not shown, similar to the plastic extension 141', in the molding process, the shoulders 1131, 1141 The longer other portion adjacent the pin ends 1132, 1142, respectively, is exposed outside of the corresponding plastic extension. The creepage distance can be adjusted in such a manner as to change the length value of the plastic extension portion 141'.

The embodiments of Figs. 8A to 8B are also based on the flow of Figs. 4A to 4C-3, similar to Figs. 4C-2 and 4C-3, the biggest difference being that in the step of forming the molded body 140 Although the susceptor 111 and the heat sink 112, and the wafer 120, the bonding regions 1130, 1140, and the lead 130 are covered by the molding body 140, the coating method is at least the pedestal 111 and the heat sink 112, respectively. The bottom surface is exposed to a bottom surface of the molding body 140 to provide a better heat dissipation path for the wafer 120.

The embodiments of Figs. 9A to 9D are also based on the flow of Figs. 4A to 4C-3, similar to Fig. 4B and Fig. 4C-1, the biggest difference is that the forked fins 112 are conventionally rounded. Instead of the square fin-shaped fin 112' of the hole, as shown in Fig. 9A, a fin 112' is connected to the other side edge of the susceptor 111 opposite to the side edge 111a to which the pin 115 is attached. In the step of forming the molding body 140, as shown in FIGS. 9B to 9C, the susceptor 111, the wafer 120, the leads 130, and the bonding regions 1130, 1140 are covered with the molding body 140, but the entire heat sink 112 is covered. 'It is completely exposed to the molding body 140, and at least the bottom surface of the base 111 is exposed to a bottom surface of the molding body 140, as shown in Fig. 9D.

In the embodiment of FIG. 10A, the position of the pin 114 of FIG. 3A is adjusted, and the intermediate pin 114 is no longer adjacent to the outer pin 113, but is remote from the pin 113 but close to the pin 115. Leading the adjacent pins 114, 115 as close as possible to each other to shorten the distance between them to form a specified set of pins in the plurality of pins 113-115, and to require the pins in the set of pins The spacing between 114 and 115 is smaller than the spacing between any one of the set of pins to the remaining one of the pins 113. The remaining pins 113 It refers to the remaining pins of all pins 113~115 except the pin groups 114~115, so the pins 113~115 appear as non-equidistant arrangement. In this embodiment, the previous N-MOSFET wafer 120 is replaced with a P-channel MOSFET wafer 120'. The P-MOSFET is typically a source connected to a high voltage, where the high voltage is relative to the drain or gate. In terms of low potential. The gate 121 ′ of the front surface of the wafer 120 ′ is electrically connected to the bonding region 1140 of the pin 114 through the lead 130 , and the source 122 ′ of the front surface is electrically connected to the bonding region 1130 of the pin 113 through the lead 130 to be a pin. 113 is connected to the high voltage, at which time the bottom drain of the back side of the wafer 120' is connected to the pedestal 111 and the pin 115. Increasing the distance between the pin groups 114, 115 and the pin 113 is equivalent to pulling apart the distance between the source and the drain, which is beneficial for improving the creepage distance. It is assumed that the pin 114 can be placed at the extreme position closest to the pin 115, which is also dependent on the process accuracy of the die-cutting machine or etching apparatus used to make the lead frame. Similarly, the two side edges of the shoulders 1131 to 1151 may be provided with corners or corners (not labeled) on either side edge thereof, or no corners are provided, which is in the foregoing. Has been explained, no longer repeat them. In the embodiment of FIG. 10B, the molding extension 141 encloses at least a portion of the shoulder 1151 of one of the pins 115 connected to the susceptor 111, and the molding extension 141 is simultaneously disconnected from the pedestal 111. At least a portion of the shoulder 1141 of one of the pins 114 near the pin 115 is covered, but the shoulder 1131 of the pin 113 that is disconnected from the pedestal 111 away from the set of pins 114, 115 is not any The plastic extension is covered. In the embodiment of FIG. 10C, the plastic extension 142 covers at least a portion of the shoulder 1131 of the pin 113, but the respective shoulders 1141, 1151 of the lead sets 114, 115 are not covered by any of the plastic extensions. live. In the embodiment of FIG. 10D, at least a portion or all of each of the base portions 1141 to 1151 is integrally covered by the plastic extension portion 141 while at least a part or all of the base portion 1131 is covered by the other plastic seal extension portion 142. Inside.

The wafers 120, 120' can also be replaced by an insulated gate bipolar transistor (IGBT). In this case, the corresponding electrode connection relationship is that the pin 114 can serve as the gate of the IGBT, but the pins 113 and 114 need to be converted into IGBTs. Collector or emitter. In some embodiments, if all the pins are arranged equidistantly, and a high voltage such as a source or a drain electrode is connected to the middle of the plurality of pins arranged side by side, the climb will be reduced. The electrical distance is because the distance between the middle high-potential pin and the low-potential pin on both sides thereof is relatively small, which is contrary to the inventive spirit of the present invention. In some embodiments, if all the pins are arranged equidistantly, in theory, it is not inappropriate to attempt to coat the base of each pin with a separate plastic extension, but in practice, the creepage is improved. The effect of the distance is very limited. For example, when the middle of the multiple pins is connected to a high voltage, the distance from the middle pin to the low potential pins on both sides is still small, and even the outermost pin is connected. The high potential, the distance from the outer pin to the middle low potential pin is still in the category of short creepage distance. In addition, if you want to cover the bases of two adjacent pins with a single plastic extension, you must ensure that a certain space gap is reserved between adjacent pins to fit the insertion of the plastic extension. Arrangement, it is necessary to open the pitch of the pins, only to increase the size of the overall device to meet the requirements of a wider space between the pins, but this costs more cost and sacrifices the performance of the device. Obviously, such a method does not use the plastic extension to simultaneously mold the respective bases of a specified set of pins, or/and to mold the base of the remaining pins of all the pins except the set of pins. The creepage distance obtained by the method is good.

The detailed description and the exemplary embodiments are given by way of illustration Various changes and modifications will no doubt become apparent to those skilled in the <RTIgt; Accordingly, the appended claims are intended to cover all such modifications and modifications Within the scope of patent application Any and all equivalent ranges and contents are considered to be within the scope and spirit of the invention.

113, 114, 115‧‧‧ pins

140‧‧‧plastic body

141‧‧‧ Plastic extension

L‧‧‧ length value

Claims (20)

A power semiconductor device, comprising: a wafer mounting unit having a pedestal and a plurality of pins, wherein a plurality of pins arranged side by side are located near a side edge of the pedestal, the first of the plurality of pins The pin is connected to the base and the second and third pins are disconnected from the base. The second and third pins respectively have a bonding area near one end of the base, and the second pin is adjacent to the first and third ends. a pin and the first, second and third pins are arranged in a non-equidistant manner; a wafer attached to the pedestal, the first electrode disposed on the back surface of the wafer is electrically connected to the pedestal through the conductive material, The second and third electrodes of the front surface of the wafer opposite to the back surface are respectively electrically connected to the respective bonding regions of the second and third pins through the conductive structure; the pedestal, the wafer, the conductive structure, and the second And a molding body covered by the bonding region of the third pin, the molding body comprising a plastic extending portion extending along a length direction of one of the first, second and third pins. The power semiconductor device according to claim 1, wherein a distance between the third pin and the second pin is set closer than between the first pin and the second pin. The power semiconductor device of claim 2, wherein a side edge of the second pin adjacent to the third pin extends parallel to a side edge of the third pin adjacent to the second pin, the second The side edge of the pin extends from the inside of the molding body to the outside of the molding body along the length of the second pin. The power semiconductor device according to claim 2, wherein the plastic package extension extends along a length direction of the second and third leads. The power semiconductor device of claim 2, wherein the side edge of the second pin adjacent to the first pin includes a corner portion adjacent to the first pin and the pedestal. The power semiconductor device according to claim 1, wherein a distance between the first pin and the second pin is set to be closer to a distance between the third pin and the second pin. The power semiconductor device of claim 6, wherein a side edge of the second pin adjacent to the first pin extends parallel to a side edge of the first pin adjacent to the second pin, the second The side edge of the pin extends from the inside of the molding body to the outside of the molding body along the length of the second pin. The power semiconductor device according to claim 6, wherein the plastic package extension extends along a length direction of the first and second leads. The power semiconductor device of claim 6, wherein a side edge of the second pin adjacent to the third pin includes a corner portion toward the third pin and toward the pedestal. The power semiconductor device according to claim 1, wherein the wafer is a MOSFET or an IGBT, the first electrode is a drain, and the second and third electrodes of the front surface of the wafer include a source and a gate. A method of packaging a power semiconductor device, comprising the steps of: providing a lead frame having a plurality of wafer mounting units, the wafer mounting unit having a base and a plurality of pins, the plurality of pins disposed side by side at the base Near the one side edge of the socket, the first pin of the plurality of pins is connected to the base, and the second and third pins are disconnected from the base, and the second and third pins are respectively disposed at one end of the second and third pins near the base. a bonding region, wherein the second pin is adjacent to the first and third pins, and the first, second, and third pins are disposed in a non-equidistant manner; Adhering the wafer to the pedestal, the first electrode disposed on the back surface of the wafer is electrically connected to the pedestal through the conductive material; and electrically connecting the plurality of electrodes on the front surface of the wafer to the pedestal Opening a plurality of pins on each of the bonding regions of the pedestal; forming a molding body, covering the pedestal, the wafer, the conductive structure, and the bonding area of each pin disconnected from the pedestal, and molding The body includes at least one plastic extension extending along a length of one of the first, second, and third pins; and the lead frame is cut to separate the wafer mounting units. The method of claim 11, wherein the third pin is disposed closer to the second pin than the first pin. The method of claim 12, wherein a side edge of the second pin adjacent to the third pin extends parallel to a side edge of the third pin adjacent to the second pin, along the second The length of the pin extends from the inside of the molded body to the outside of the molded body. The method of claim 12, wherein the plastic extension extends along a length of the second and third pins. The method of claim 12, wherein the side edge of the second pin adjacent to the first pin includes a corner toward the first pin and toward the base. The method of claim 11, wherein the first pin is closer to the second pin than the third pin. The method of claim 16, wherein a side edge of the second pin adjacent to the first pin extends parallel to a side edge of the first pin adjacent to the second pin, along the second The length of the pin extends from the inside of the molded body to the outside of the molded body. The method of claim 16, wherein the plastic extension extends along the length of the first and second pins. The method of claim 16, wherein the second pin comprises a corner adjacent to a side edge of the third pin, toward the third pin and toward the base. The method of claim 11, wherein the wafer is a MOSFET or an IGBT, the first electrode is a drain, and the second and third electrodes disposed on the front surface of the wafer include a source and a gate.