JP3699966B2 - Lead frame, resin-encapsulated semiconductor device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a resin-encapsulated semiconductor device in which a surface on which a semiconductor chip is mounted on a lead frame is encapsulated with an encapsulating resin, and a land electrode serving as an external electrode is exposed on the bottom surface, and the resin-encapsulated semiconductor The present invention relates to a lead frame used in the apparatus.

  In recent years, in order to cope with the downsizing of electronic devices, high-density mounting of semiconductor components has been increasingly demanded, and along with this, downsizing and thinning of semiconductor devices are progressing. Furthermore, various devices have been made to improve production cost and productivity. Hereinafter, a lead frame used in a conventional resin-encapsulated semiconductor device and a processing method thereof will be described.

  FIG. 12 is a diagram showing the structure of a lead frame used in the conventional resin-encapsulated semiconductor device disclosed in Patent Document 1. In FIG. As shown in the figure, this conventional lead frame includes a die pad 1001 on which a semiconductor chip is mounted, a suspension frame 1002 connected to a frame frame 1002 at the end and supporting the four corners of the die pad 1001 at the tip, and a tip thereof. It has a linear land lead 1004 and a lead 1005 whose part faces the die pad 1001 and whose end part is connected to the frame frame 1002. Each bottom surface portion of the land lead 1004 and the lead 1005 constitutes an external terminal (land portion), and the lead 1005 can be connected to the mounting substrate as an external terminal on the outer side surface portion in addition to the bottom surface. It is configured. Further, the tip portion of the land lead 1004 extends beyond the tip portion of the lead 1005 to a portion close to the die pad 1001.

  The die pad 1001 is provided with a circular protrusion 1006 that protrudes upward at a substantially central portion of the surface. The protrusion 1006 presses the flat plate constituting the die pad 1001 in a half-cut state by pressing. It is formed by applying and projecting upward. The protrusion 1006 substantially becomes a part that supports the semiconductor chip, and when the semiconductor chip is mounted, a gap is formed between the surface of the die pad 1001 excluding the protrusion 1006 and the back surface of the semiconductor chip. A groove portion 1007 is provided in a region surrounding the protruding portion 1006 on the surface of the die pad 1001, and the sealing resin is provided so as to enter the groove portion 1007 when the semiconductor chip is mounted and resin-sealed.

When a semiconductor chip is mounted with a lead frame having such a configuration, the semiconductor chip and each lead are connected with a thin metal wire, and the resin-sealed semiconductor device is configured by resin sealing, the resin-sealed semiconductor On the bottom surface of the device, that is, on the bottom surface of the package, the bottom surface of the land portion 1008 having a curved tip portion is disposed, and the bottom surface portion having the curved tip portion of the lead 1005 is disposed outside the land portion 1008. Thus, staggered two-row external terminals are configured. Thereby, an LGA (land grid array) type package can be configured.
JP 2001-77274 A

  However, the conventional lead frame has the following problems.

  Although an LGA having land portions arranged in a plurality of rows can be obtained by a conventional lead frame, the land portions cannot be disposed at a portion where the suspension lead 1003 fixing the die pad 1001 exists. Therefore, there is a restriction when increasing the number of land portions (terminal electrodes).

  In addition, since there are suspension leads, when a semiconductor device using this lead frame is produced, the semiconductor device is warped due to the difference in thermal shrinkage between the die pad and the resin portion during resin sealing. It was.

  Furthermore, another problem is that the number of processing steps before sheet attachment increases, resulting in an increase in cost.

  An object of the present invention is to use a lead frame suitable for manufacturing a resin-encapsulated semiconductor device having high productivity, low cost, and high quality, corresponding to the further increase in variety and terminals of semiconductor devices. A resin-encapsulated semiconductor device and a method for manufacturing the same are provided.

A first lead frame of the present invention includes a lead having an island portion whose upper surface is a bonding pad and the lowermost portion is an external terminal, and a connecting portion connecting the outer frame-island portion-island portion-die pad, and the outer frame And a land that is connected to the outer frame through the connecting portion and has a larger area than the island portion, and eliminates a lead that functions as a suspension lead during resin sealing.

Thereby, since the external terminals can be arranged instead of the suspension leads normally arranged at the corner portions, a resin-encapsulated semiconductor device in which the external terminals are arranged at a high density can be obtained. In addition, deformation and movement of the die pad, which are likely to occur due to the presence of the suspension leads, can be suppressed. In addition, since a land having a larger area than the island portion is provided in the corner portion, when the resin-encapsulated semiconductor device formed using the first lead frame is mounted on the motherboard (secondary mounting), It is possible to improve the bonding strength between the resin-encapsulated semiconductor device and the mother board by solder or the like.

  The lowermost part of each island part has substantially the same planar shape and is arranged in a lattice shape, so that higher-density mounting is possible.

  It is preferable that the lowermost part of each island is arranged in a plurality of rows of three or more along each side of the outer frame.

  The second lead frame of the present invention is provided with a thin film portion lacking a lower portion on the outer peripheral portion of the die pad and a heat radiating terminal protruding downward from the lower surface of the thin film portion, and the upper surface serves as a bonding pad and the lowermost portion serves as an external terminal. A lead having an island part and a connecting part for connecting the outer frame-island part-island part-heat dissipating terminal is provided.

Thus, after the resin-encapsulated semiconductor device using the lead frame is formed, when the resin-encapsulated semiconductor device is mounted on the motherboard, the external terminals and the heat radiating terminals are collectively reflowed by solder reflow. Etc., so that the mounting can be stabilized and facilitated. In addition, by providing the heat dissipation terminal on the die pad, the island portion can be smoothly suppressed while suppressing the deformation of the lead in the lead cutting process when the resin-encapsulated semiconductor device is formed using the second lead frame. And the die pad can be separated from the outer frame.

  Each island part and each heat radiating terminal have substantially the same planar shape and are arranged in a lattice shape, thereby enabling higher density mounting.

  Each island part and each heat radiation terminal are preferably arranged at a substantially constant pitch in at least one direction, and each island part is arranged in a plurality of rows of 3 or more along each side of the outer frame. It is preferable that they are arranged.

The first resin-encapsulated semiconductor device of the present invention is formed using a first lead frame, the upper surface is a bonding pad for connecting a thin metal wire, and the lowermost portion is an external terminal. An island portion, and a sealing resin that seals the semiconductor chip, the island portion, the die pad, and the like with the island portion, the bottom of the land portion and the land , and at least a part of the bottom surface of the die pad exposed, and extending from the die pad The member whose tip is exposed on the surface of the sealing resin is not provided.

  Thereby, since the external terminals can be arranged instead of the suspension leads normally arranged at the corner portions, a resin-encapsulated semiconductor device in which the external terminals are arranged at a high density can be obtained.

  Each external terminal has substantially the same planar shape and is arranged in a grid pattern on the back surface of the sealing resin, so that higher density mounting is possible.

  Each external terminal is preferably arranged in a plurality of rows of three or more on the back surface of the sealing resin along the outer periphery.

  The second resin-encapsulated semiconductor device of the present invention is formed using the second lead frame, and is provided along the outer peripheral part of the main body part and the thin film part lacking the lower part, and the thin film part A die pad having a plurality of heat dissipating terminals provided so as to protrude downward from the lower surface of the metal, an island where the upper surface is a bonding pad for connecting a fine metal wire and the lowermost portion is an external terminal, A sealing resin for sealing the semiconductor chip, the island, the lead, the die pad, and the like is provided with the lower portion and the lowermost portion of the heat radiating terminal exposed.

  As a result, when the resin-encapsulated semiconductor device is mounted on the motherboard, the external terminals and the heat radiating terminals can be connected to the electrodes of the motherboard by batch reflow of solder, so that the mounting can be stabilized and facilitated. it can.

  Each external terminal and each heat radiating terminal have substantially the same planar shape and are arranged in a grid pattern on the back surface of the sealing resin, thereby realizing easy mounting and high-density mounting. be able to.

  Each external terminal and each heat radiating terminal are preferably arranged at a substantially constant pitch in at least one direction, and each external terminal has a plurality of rows of three or more rows on the back surface of the sealing resin along the outer periphery. It is preferable to arrange | position.

  In the first method for manufacturing a resin-encapsulated semiconductor device according to the present invention, after preparing the first lead frame, a die-bonding step and a step of dividing the connecting portion of the lead frame on the sealing sheet are performed. Therefore, electrical connection and resin sealing with the sealing sheet attached to the lead frame are performed.

  By this method, even if there is no suspension lead, the position of the die pad and the island portion can be stabilized, electrical connection and resin sealing can be performed, and the resin-encapsulated semiconductor device in which external terminals are arranged at high density Is obtained.

  According to the second method for manufacturing a resin-encapsulated semiconductor device of the present invention, after preparing the second lead frame, a die-bonding step and a step of dividing the connecting portion of the lead frame on the sealing sheet are performed. Therefore, electrical connection and resin sealing with the sealing sheet attached to the lead frame are performed.

  By this method, the position of the die pad and island can be stabilized, electrical connection and resin sealing can be performed, and the heat radiation terminals can be juxtaposed with the external terminals and protruded from the back surface of the sealing resin to the motherboard. A resin-encapsulated semiconductor device that can be easily mounted is obtained.

  According to the first lead frame of the present invention, the resin-encapsulated semiconductor device using the same, and the method for manufacturing the same, a resin-encapsulated semiconductor device having external terminals provided at a high density as much as there are no suspended leads is obtained. Is possible.

  According to the second lead frame of the present invention, the resin-encapsulated semiconductor device using the same, and the method of manufacturing the same, the heat dissipation terminals arranged along with the external terminals are provided on the die pad, so that the mounting can be facilitated. .

(First embodiment)
-Lead frame structure-
1A and 1B are a plan view of a lead frame according to the first embodiment of the present invention and a cross-sectional view taken along line IB-IB in FIG. 1A, respectively. FIG. 1A shows a part of a lead frame LF1 in which a plurality of semiconductor chip mounting regions are continuously provided in a grid pattern, that is, only a region for mounting one semiconductor chip. Yes. The lead frame LF1 is obtained by processing a copper alloy plate by etching, punching press or the like.

  As shown in FIGS. 1A and 1B, the lead frame LF1 of the present embodiment includes a rectangular outer frame 100 having four sides surrounding the chip mounting area Rtp, and a central portion of the chip mounting area Rtp. A die pad 101 for mounting a semiconductor chip, a lead 102 extending from the outer frame 100 and connected to the die pad 101, and a reinforcing land 103.

  The lead 102 according to this embodiment includes an island 104 having a wide width (for example, 20 μm to 120 μm) and a thick wall (for example, 20 μm to 120 μm), and a connecting portion 105 having a thin width (for example, 15 μm to 100 μm) and a thin wall (for example, 15 μm to 100 μm). Are arranged alternately. The upper surface of the island part 104 functions as a bonding pad 104a to which a thin metal wire is connected. Further, in the process of mounting the semiconductor chip on the lead frame LF1, resin sealing is performed with the lower surface of the island portion 104 fixed to a sealing sheet having an adhesive layer. It functions as a land electrode 104b (external terminal) protruding downward from the back surface of the sealing resin. The connecting part 105 connects between the outer frame 100 and the island part 104, between the island parts 104, and between the island part 104 and the die pad 101. The connection part 105 lacks the lower part by press working or etching with a metal mold, and is a part embedded in the sealing resin in the process of mounting the semiconductor chip on the lead frame LF1. The connecting portion 105 is continuous with the upper portion of the island portion 104, and the upper surface of the connecting portion 105 forms a common plane with the upper surface of the island portion 104.

  Here, the features of the lead frame LF1 of the present embodiment will be described. In the lead frame LF1 of the present embodiment, there is no member that only functions as a suspension lead, which is present in a normal lead frame. That is, there is no lead where the island 104 is not provided. Therefore, the die pad of the lead frame LF1 of the present embodiment is not connected to the outer frame during the resin sealing process, and no leads that function as suspension leads during the resin sealing process are provided. That is, in the resin-encapsulated semiconductor device, there is no lead extending from the die pad 101 and exposed on the surface of the encapsulating resin.

  In the lead frame LF1 of this embodiment, the island portion 104 (that is, the bonding pad 104a and the land electrode 104b) is also disposed on the line connecting the corner portion of the die pad 101 and the corner portion of the outer frame 100. . In addition, in the lead frame LF1 of the present embodiment, a lead 102x (or 102x) connected to a lead 102y (or 102x) extending from another side adjacent to one side of the outer frame 100 to which the lead is connected in the vicinity of the corner portion. Or 102y). That is, there is a lead 102x (or 102y) connected to the die pad 101 via another lead 102y (or 102x). Furthermore, the lead frame LF1 of the present embodiment is provided with a reinforcing land 103 having a much larger area (for example, a diameter of 300 μm to 1500 μm) than the island portion 104, which is directly connected to the outer frame 100 at the corner portion. ing.

  And each land electrode (external terminal) 104b which is the lowest part of each island part 104 has the substantially same planar shape, and is arranged in the grid | lattice form. Here, “substantially the same” means the same when not taking into account variations during manufacturing.

  According to the lead frame LF1 of the present embodiment, the lead extending from two adjacent sides of the outer frame 100 is connected to each other at the corner portion without providing the suspension lead, thereby including the land electrode 104b ( It is possible to form a resin-encapsulated semiconductor device in which external terminals are arranged in a plurality of rows along each side of the outer frame 100. That is, when there is a suspension lead at the corner as in the conventional lead frame, the land electrode can be provided in the middle of the suspension lead, but the suspension lead is connected to the die pad, so These land electrodes are only used for reinforcement or for terminals having the same potential as the die pad (for example, a ground terminal). On the other hand, in the lead frame LF1 of the present embodiment, land electrodes that function as signal terminals can be disposed up to the corner portion, and land electrodes can be disposed at high density. In other words, restrictions on the location and number of land electrodes can be relaxed.

  Further, as will be described later, in the step of resin sealing using the lead frame LF1 of the present embodiment, each land electrode 104 (island portion 102) and the die pad 101 are separated from each other without being connected to each other. Since each is supported by the sealing sheet, the warpage generated due to the difference in thermal shrinkage between the lead frame main body and the sealing resin is individually divided, and the amount of warpage of the entire semiconductor device can be reduced.

  Further, since the lead frame LF1 of the present embodiment is provided with the reinforcing land 103 having a large circular pattern at the corner portion, when the resin-encapsulated semiconductor device is mounted on the motherboard (secondary mounting). Further, it is possible to improve the bonding strength between the resin-encapsulated semiconductor device and the mother board by solder or the like.

  However, the reinforcing land 103 in the lead frame LF1 of the present embodiment is not necessarily provided. When the reinforcing land 103 does not exist, land electrodes (island portions) can be arranged in the space, so that the land electrodes can be arranged at a higher density.

-Manufacturing process of resin-encapsulated semiconductor devices-
Next, an example of a manufacturing process of a resin-encapsulated semiconductor device using the lead frame LF1 of the present embodiment will be described. 2A and 2B are a plan view and a cross-sectional view taken along the line IIB-IIB showing a process of upsetting the central portion of the die pad in the manufacturing process of the resin-encapsulated semiconductor device of the first embodiment. is there. 3A and 3B are a plan view and a IIIB-IIIB line showing a process of placing the lead frame on the sealing sheet in the manufacturing process of the resin-encapsulated semiconductor device of the first embodiment. FIG. 4A and 4B are a plan view and a cross-sectional view taken along the line IVB-IVB, showing a process of dividing the leads in the manufacturing process of the resin-encapsulated semiconductor device of the first embodiment. FIG. 5 is a partial cross-sectional view showing the resin sealing step in the manufacturing steps of the resin-encapsulated semiconductor device of the first embodiment. 6A and 6B are a cross-sectional view and a rear view taken along line VIA-VIA showing the structure after the resin sealing step of the resin-encapsulated semiconductor device of the first embodiment.

  First, in a process shown in FIGS. 2A and 2B, a metal plate made of an alloy mainly composed of copper (Cu) or an alloy of iron (Fe) and nickel (Ni) is integrally formed by stamping or etching. Thus, a lead frame LF1 having the structure shown in FIGS. 1A and 1B is prepared. Next, a circular protrusion 101a is formed on the die pad 101 by pressing the lead frame LF1 using an upper half-cutting die and a lower pressing die (both not shown). This process is intended to upset the semiconductor chip and support it on the die pad 101, but the protrusion 101a is not necessarily provided. In addition, the lead frame LF1 is partially or entirely plated for bonding and mounting with the semiconductor chip. As the type of plating, Ag plating, Au plating, Ni—Pd—Au plating, or the like can be used.

  Next, in the steps shown in FIGS. 3A and 3B, the sealing sheet is attached so as to be in close contact with the back surface of the lead frame LF1, that is, the lower surface of the main body portion of the die pad 101, the reinforcing land 103, and the island portion 104. 150 is pasted. An adhesive layer is provided on the upper surface of the sealing sheet 150, and the die pad 101, the reinforcing land 103, and the island portion 104 of the lead 102 are fixed on the sealing sheet 150 in an isolated state. Yes.

  Next, in the process shown in FIGS. 4A and 4B, the lead 102 is cut into the cut portions Ct1, Ct2, C.sub.t2, Ct2, by pressing using a mold with the lead frame LF1 fixed on the sealing sheet 150. Divide at Ct3. That is, the connecting portion 105 between the island portion 104 of the lead 102 and the die pad 101, the connecting portion 105 between the island portions 104, and the connecting portion 105 between the island portion 104 and the outer frame 100 are cut. The die pad 101 and each island 104 are isolated.

  Next, although illustration of the process is omitted, the semiconductor chip 160 is mounted on the die pad 101 in each chip mounting region Rtp of the lead frame LF1 in a state where the lead frame LF1 is mounted on the sealing sheet 150 (die bonding process). ), The pad electrode of the semiconductor chip 160 and the bonding pad 104a of the island portion 104 are connected by a thin metal wire 170 as a connecting member (wire bonding step).

  Then, as shown in FIG. 5, the lead frame LF1 is set in a sealing mold including an upper mold 180a and a lower mold 180b having a die cavity. That is, the lead frame LF1 is set in a sealing mold so that the semiconductor chip 150, the fine metal wire 170, etc. enter the die cavity, and the space between the upper mold 180a and the lower mold 180b is pressed into the die cavity. Fill with sealing resin.

  After the resin sealing step, the sealing sheet 150 is peeled off from the lead frame LF1 and the sealing resin, and then a large number of resin-encapsulated semiconductor devices formed on the lead frame LF1 are cut out individually. As a result, a resin-encapsulated semiconductor device having the structure shown in FIGS. 6A and 6B is obtained. However, in the cross-sectional view shown in FIG. 6A, the horizontal dimension of the right half is reduced to the same dimension as the horizontal dimension of the left half.

  6A and 6B, the land electrode 104b, which is the lowermost part of the island part 104 of the lead frame LF1, the lowermost part of the die pad 101, and the lowermost part of the reinforcing land 103 are formed from the sealing resin 190. It protrudes downward. In particular, it can be seen that the land electrodes 104b are arranged in a plurality of rows at a constant pitch (interval) P1 in the vertical and horizontal directions in FIG. In the resin-encapsulated semiconductor device, there is no lead extending from the die pad 101 and exposed on the surface of the encapsulating resin.

  The spacing between the land electrodes 104b is not necessarily constant, and even when they are arranged at a constant pitch, the pitch may be different between the vertical direction and the horizontal direction in FIG. By arranging the land electrodes 104b at a constant pitch in this way, a resin-encapsulated semiconductor device that conforms to the standard of an actual semiconductor device can be obtained.

  According to the resin-encapsulated semiconductor device of the present embodiment, the existing suspension leads are eliminated, the islands 104 of the leads 102 and the islands 104 of the leads 102, the islands 104 in the leads 102, the islands, Since the connecting portion 105 having a narrower width and thinner than the island portion 104 is interposed between the portion 104 and the outer frame 100, a semiconductor is connected to the lead frame LF1 in the steps shown in FIGS. 4 (a) and 4 (b). A member that easily cuts between the island portions 104 in the leads 102 and between the island portions 104 and the outer frame 100 in a state where the chip 160 is mounted, and connects between the die pad 101 and the outer frame 100. The wire bonding process or the resin sealing process can be performed in a state in which no exists.

  Therefore, it is possible to save the troubles such as etching and die cutting for forming the suspension leads, and as shown in FIGS. 6A and 6B, the resin-encapsulated semiconductor device in which the land electrodes 104b are arranged at a high density. Will be obtained.

(Second Embodiment)
7A and 7B are a plan view and a cross-sectional view taken along the line VIIB-VIIB, respectively, of a lead frame according to the second embodiment of the present invention. FIG. 7A shows a part of the lead frame LF2 in which a plurality of semiconductor chip mounting regions are continuously provided in a grid pattern, that is, only a region for mounting one semiconductor chip. Yes. The lead frame LF2 is obtained by processing a copper alloy plate by etching, punching press or the like.

  As shown in FIGS. 7A and 7B, the lead frame LF2 of the present embodiment includes a rectangular outer frame 200 having four sides surrounding the chip mounting area Rtp, and a central portion of the chip mounting area Rtp. A die pad 201 for mounting a semiconductor chip, a lead 202 extending from the outer frame 200 and connected to the die pad 201, a reinforcing land 203, and a heat dissipation terminal 201b provided on the outer periphery of the die pad 201 and connected to the lead 202. I have.

  The lead 202 of this embodiment includes a wide (for example, 20 μm to 120 μm) and thick (for example, 20 μm to 120 μm) island part 204 and a thin (for example, 15 μm to 100 μm) and thin (for example, 15 μm to 100 μm) connection part 205. Are arranged alternately. The upper surface of the island part 204 functions as a bonding pad 204a to which a thin metal wire is connected. Further, in the process of mounting the semiconductor chip on the lead frame LF2, the bottom surface of the island part 204 is resin-sealed in a state of being fixed to a sealing sheet having an adhesive layer, and the lowermost part of the island part 204 is sealed with the resin. It functions as a land electrode 204b protruding downward from the back surface of the sealing resin. The connecting portion 205 connects between the outer frame 200 and the island portion 204, between the island portions 204, and between the island portion 204 and the heat radiating terminal 201 b of the die pad 201. The lower part of the connecting part 205 is lacking due to press working or etching with a metal mold, and is embedded in the sealing resin in the process of mounting the semiconductor chip on the lead frame LF2. The connecting portion 205 is continuous with the upper portion of the island portion 204, and the upper surface of the connecting portion 205 forms a common plane with the upper surface of the island portion 204.

  Here, features of the lead frame LF2 of the present embodiment will be described. In the lead frame LF2 of the present embodiment, there is no suspension lead having only a function of supporting a die pad, which is present in a normal lead frame. In addition, since the die pad of the lead frame LF2 of the present embodiment is connected to the outer frame only by the divided leads 202 during the resin sealing process, it functions as a suspension lead during the resin sealing process. No lead is provided. In the lead frame LF2 of the present embodiment, the island portion 204 (that is, the bonding pad 204a and the land electrode 204b) is also disposed on the line connecting the corner portion of the die pad 201 and the corner portion of the outer frame 200. . Further, the lead frame LF2 of the present embodiment extends from another side adjacent to one side of the outer frame 200 to which the lead 202x (or 202y) is connected without being directly connected to the die pad 201 in the vicinity of the corner portion. There is a lead 202x (or 202y) connected to the lead 202y (or 202x). That is, there is a lead 202x (or 202y) connected to the die pad 201 via a lead 202y (or 202x) extending from another side adjacent to one side of the outer frame 200 to which the lead 202x (or 202y) is connected. ing. Further, in the lead frame LF2 of the present embodiment, a reinforcing land 203 having a much larger area (for example, a diameter of 300 μm to 1500 μm) than the island portion 204 is provided at a corner portion close to the outer frame 200.

  In addition to the same features as the lead frame LF1 of the first embodiment, the lead frame LF2 of the present embodiment has the following features. That is, the outer peripheral portion of the die pad 201 is a thin film portion 201c lacking a lower portion, and a heat dissipation terminal 201b protruding downward from the lower surface of the thin film portion 201c is provided. Such a shape is formed by removing the lower part of the outer periphery of the die pad 201 while leaving the part that becomes the heat radiating terminal 201b by half etching or pressing.

  In the present embodiment, each land electrode (external terminal) 204b, which is the lowermost part of each island part 204, and the lowermost part of the heat radiating terminal 201b have substantially the same planar shape, and are arranged in a grid pattern. Has been. Here, “substantially the same” means the same when not taking into account variations during manufacturing. However, even if each land electrode (external terminal) 204b, which is the lowermost part of each island part 204, and the lowermost part of the heat radiating terminal 201b do not have substantially the same planar shape, they will be described later. It is possible to exert an effect.

  By providing the heat dissipating terminal 201b, the lead frame of this embodiment can exhibit the following special effects in addition to the same effects as those of the first embodiment.

  In the manufacturing process of a resin-encapsulated semiconductor device having an LGA (land grid array) structure using the lead frame LF1 of the first embodiment, the island portion 104 of the lead 102 and the die pad 101 are cut by punching. There is a possibility that a defect such as deformation of the lead may occur after cutting. Therefore, in order to avoid this, as shown in FIGS. 1A and 1B, the connecting portion 105 between the island portion 104 and the die pad 101 is made more than the connecting portion 105 between the island portions 104. There was a need to lengthen. However, as the number of land electrodes increases in the future, it is likely to be further deformed due to the complexity of the punched shape, and the productivity may be deteriorated.

  However, as in the present embodiment, by providing the heat dissipating terminals 201b on the die pad 201, the island portion 204 and the die pad 201 can be smoothly connected to the outer frame 200 while suppressing deformation of the lead 202 in the lead 202 cutting step described later. It becomes possible to separate from. As a result, since the connecting portion 205 that connects the most distal island portion 204 of the lead 202 and the heat radiating terminal 201b can be shortened, the island portions 204 (land electrodes 204b) can be arranged with higher density.

  Also, due to the presence of the heat dissipation terminal 201b, when mounting a resin-encapsulated semiconductor device, which will be described later, on the mother board, the main body portion of the die pad 201, which is likely to cause poor bonding, is not joined to the mother board, but by reflow soldering, Only the heat dissipating terminal 201b can be joined to the electrode of the mother board together with the land electrode 204b. And, without joining the main body of the die pad 201 and the mother board, the heat radiation terminal 201b can quickly release the heat generated from the semiconductor chip to the mother board. In the present embodiment, considering that the heat dissipation function is saturated when the heat dissipation area exceeds a certain area, the total area of the lower surfaces of the plurality of heat dissipation terminals 201b allows the heat generation of the semiconductor chip to escape to the motherboard side quickly and the semiconductor chip. The function of the semiconductor element is set so as not to be impaired. Therefore, the heat dissipation function of the resin-encapsulated semiconductor device using the lead frame of this embodiment can be maintained equivalent to that of the first embodiment.

-Manufacturing process of resin-encapsulated semiconductor devices-
Next, an example of a manufacturing process of a resin-encapsulated semiconductor device using the lead frame LF2 of this embodiment will be described. 8A and 8B show a process of upsetting the central portion of the die pad and placing the lead frame on the sealing sheet in the manufacturing process of the resin-encapsulated semiconductor device of the second embodiment. It is sectional drawing in the top view and VIIIB-VIIIB line | wire which show. FIGS. 9A and 9B are a plan view and a cross-sectional view taken along the line IXB-IXB showing a step of dividing the leads in the manufacturing process of the resin-encapsulated semiconductor device of the second embodiment. 10A and 10B are a cross-sectional view and a rear view taken along line XA-XA showing the structure after the resin sealing step of the resin-encapsulated semiconductor device of the second embodiment.

  First, in a process shown in FIGS. 8A and 8B, a metal plate made of an alloy mainly composed of copper (Cu) or an alloy of iron (Fe) and nickel (Ni) is integrally formed by stamping or etching. Thus, a lead frame LF2 having the structure shown in FIGS. 7A and 7B is prepared. Next, a circular protrusion 201a is formed on the die pad 201 by pressing the lead frame LF2 using an upper half-cutting die and a lower pressing die (both not shown). This process is intended to upset the semiconductor chip and support it on the die pad 201, but the protrusion 201a is not necessarily provided. . In addition, the lead frame LF2 is partially or entirely plated for bonding with semiconductor chips and mounting. As the type of plating, Ag plating, Au plating, Ni—Pd—Au plating, or the like can be used.

  Next, the sealing sheet 250 is attached so as to be in close contact with the back surface of the lead frame LF2, that is, the lower surfaces of the die pad 201, the reinforcing land 203, and the island portion 204. An adhesive layer is provided on the upper surface of the sealing sheet 250, and the main body portion of the die pad 201, the heat radiation terminal 201 b of the die pad 201, the reinforcing land 203, and the island portion 204 of the lead 202 are isolated by this adhesive layer. It is fixed on the sealing sheet 250.

  Next, in the process shown in FIGS. 9A and 9B, the island 204 of the lead 202 and the die pad 201 are pressed by pressing using a mold in a state where the lead frame LF2 is fixed on the sealing sheet 250. The connecting portion 205 between the heat radiation terminal 201b, the connecting portion 205 between the island portions 204, and the connecting portion 205 between the island portion 204 and the outer frame 200 are cut, respectively, to form the die pad 201 and each island portion. 204 is isolated. At this time, there is no member connecting the die pad 201 and the outer frame 200.

  Next, although illustration of the process is omitted, the semiconductor chip 260 is mounted on the die pad 201 in each chip mounting region Rtp of the lead frame LF2 with the lead frame LF2 placed on the sealing sheet 250 (die bonding process). ), The pad electrode of the semiconductor chip 260 and the bonding pad 204a of the island portion 204 are connected by the metal thin wire 270 as a connecting member (wire bonding step).

  Then, similarly to the process shown in FIG. 5 in the first embodiment, the lead frame LF2 is set in a sealing mold including an upper mold 180a having a die cavity and a lower mold 180b. That is, the lead frame LF2 is set in a sealing mold so that the semiconductor chip 260, the fine metal wire 270 and the like enter the die cavity, and the space between the upper mold 180a and the lower mold 180b is pressed into the die cavity. Fill with sealing resin.

  After the resin sealing step is finished, the sealing sheet 250 is peeled off from the lead frame LF2 and the sealing resin, and then a large number of resin-encapsulated semiconductor devices formed on the lead frame LF2 are cut out individually. As a result, a resin-encapsulated semiconductor device having the structure shown in FIGS. 10A and 10B is obtained. However, in the cross-sectional view shown in FIG. 10A, the horizontal dimension of the right half is reduced to the same dimension as the horizontal dimension of the left half.

  As shown in FIGS. 10A and 10B, the land electrode 204b which is the lowermost part of the island part 204 of the lead frame LF2, the lowermost part of the main body part of the die pad 201, the lowermost part of the heat radiation terminal 201b of the die pad 201, The lowermost portion of the reinforcing land 203 protrudes downward from the sealing resin 290. In particular, the heat dissipating terminals 201b and the land electrodes 204b are arranged in a plurality of rows of 3 or more at a constant pitch (interval) P2 in the vertical and horizontal directions in FIG. I understand that.

  Thereafter, when the resin-encapsulated semiconductor device is mounted on the mother board, the land electrode 204b and the heat radiation terminal 201b may be connected to each electrode of the mother board by solder reflow, and the main body of the die pad 201 needs to be connected to the mother board. There is no.

  According to the resin-encapsulated semiconductor device of the present embodiment, the existing suspension leads are eliminated, the islands 204 of the leads 202 and the islands 204 of the leads 202, the islands 204 in the leads 202, Since the connecting portion 205 having a narrower width and thinner than the island portion 204 is interposed between the portion 204 and the outer frame 200, a semiconductor is connected to the lead frame LF2 in the steps shown in FIGS. 9A and 9B. A member that easily cuts between the islands 204 in the lead 202 and between the islands 204 and the outer frame 200 in a state where the chip 260 is mounted, and connects the die pad 201 and the outer frame 200. The wire bonding process or the resin sealing process can be performed in a state in which no exists.

  Therefore, it is possible to save the trouble of etching, die cutting and the like for forming the suspension lead, and as already described, by providing the heat dissipation terminal 201b, the land electrode 204b can be made more dense than the first embodiment. Can be arranged.

  Further, since the heat dissipating terminal 201b is provided on the die pad 201, the resin-sealed mold can be bonded to the motherboard electrode or the like together with the land electrode 204b by batch reflow of solder in the mounting process. It became possible. That is, when mounting the resin-encapsulated semiconductor device, it is no longer necessary to connect the main body of the die pad 201 to the motherboard for heat dissipation, so that connection failure can be reduced and heat dissipation is maintained high. However, the mounting can be facilitated.

  The distance between the heat radiating terminal 201b and the land electrode 204b and the distance between the land electrodes 204b are not necessarily constant, and even when they are arranged at a constant pitch, the vertical direction and the horizontal direction in FIG. The pitch may differ depending on the direction. However, in particular, the radiating terminal 201b and the island portion 204 have substantially the same planar shape, and the connecting portion 205 between the radiating terminal 201b and the island portion 204 is the same as the connecting portion 205 between the island portions 204. It is preferable that they have substantially the same planar shape. As a result, the heat dissipating terminals 201b and the land electrodes 204b are arranged at a constant pitch, which facilitates batch reflow of solder and facilitates mounting when mounting the resin-encapsulated semiconductor device. is there.

(Other embodiments)
FIGS. 11A and 11B are a plan view of a lead frame according to a modification of the second embodiment of the present invention and a cross-sectional view taken along line XIB-XIB in FIG. 11A, respectively. FIG. 11A shows a part of the lead frame LF2 in which a plurality of semiconductor chip mounting regions are continuously provided in a grid pattern, that is, only a region for mounting one semiconductor chip. Yes. The lead frame LF3 is obtained by processing a copper alloy plate by etching, punching press or the like.

  As shown in FIGS. 11A and 11B, the lead frame LF3 of the present modification includes a rectangular outer frame 300 having four sides surrounding the chip mounting area Rtp, and a central portion of the chip mounting area Rtp. A die pad 301 for mounting a semiconductor chip, a lead 302 extending from the outer frame 300 and connected to the die pad 301, a reinforcing land 303, and a heat dissipation terminal 301 b provided on the outer periphery of the die pad 301 and connected to the lead 302. I have.

  The lead 302 of this modification has an island 304 having a wide width (for example, 20 μm to 120 μm) and a thick wall (for example, 20 μm to 120 μm), and a thin width (for example, 15 μm to 100 μm) and a thin wall (for example, 15 μm to 100 μm). The connecting portions 305 are alternately arranged. The upper surface of the island part 304 functions as a bonding pad 304a to which a thin metal wire is connected. Further, in the process of mounting the semiconductor chip on the lead frame LF3, resin sealing is performed with the lower surface of the island 304 fixed to a sealing sheet having an adhesive layer, and the lowermost part is sealed with resin after sealing It functions as a land electrode 304b that protrudes downward from the back surface. The connecting part 305 connects between the outer frame 300 and the island part 304, between the island parts 304, and between the island part 304 and the heat dissipation terminal 301 b of the die pad 301. The lower part of the connecting part 305 is lacking due to press working or etching with a metal mold, and is embedded in the sealing resin in the process of mounting the semiconductor chip on the lead frame LF3. The connecting portion 305 is continuous with the upper portion of the island portion 304, and the upper surface of the connecting portion 305 forms a common plane with the upper surface of the island portion 304.

  Here, in the lead frame LF3 of the present modification, there is a lead that functions as a suspension lead during the resin sealing step. In other words, unlike the lead frame LF2 of the second embodiment, the lead frame LF3 of the present modification is provided with a suspension lead 309 that is directly connected to the die pad 301 in the vicinity of the corner portion. Therefore, unlike the second embodiment, there is no lead connected to a lead extending from another adjacent side. The lead 302x (or 302y) arranged at the corner is connected to another lead 302x (or 302y) extending from the same side as one side of the outer frame 300 to which the lead 302x (or 302y) is connected. Yes.

  Also in the lead frame LF3 of this modification, a reinforcing land 303 having a larger area (for example, a diameter of 300 μm to 1500 μm) than the island portion 304 is provided at a corner portion close to the outer frame 300.

  According to this modification, as in the second embodiment, the effect of improving heat dissipation due to the presence of the heat radiating terminal 301b and the effect of arranging the high density of the land electrodes 304b can be exhibited. However, the presence of the suspension leads 309 causes the high density arrangement effect of the land electrodes 304b to be inferior to that of the second embodiment, but the holding stability of the die pad 301 in the cutting process of the leads 302 is higher than that of the second embodiment. Is also excellent.

  In the first embodiment, the second embodiment, and modifications thereof, a connecting portion that connects island portions of adjacent leads may be provided. In this case, since the island portions are connected in a lattice shape in both the vertical and horizontal directions, the function of stably maintaining the shape of the lead frame is improved until the leads are cut.

  The lead frame and the resin-encapsulated semiconductor device of the present invention can be used as electronic components mounted on personal computers, home appliances, communication devices, and the like.

(A), (b) is the top view of the lead frame which concerns on the 1st Embodiment of this invention, respectively, and sectional drawing in the IB-IB line, respectively. (A), (b) is the top view which shows the process of upsetting the center part of a die pad among the manufacturing processes of the resin-encapsulated semiconductor device of 1st Embodiment, and sectional drawing in the IIB-IIB line | wire. (A), (b) is the top view which shows the process of mounting the lead frame on a sealing sheet among the manufacturing processes of the resin-encapsulated semiconductor device of 1st Embodiment, and the cross section in a IIIB-IIIB line | wire FIG. (A), (b) is the top view which shows the process of parting a lead | read | reed among the manufacturing processes of the resin-encapsulated semiconductor device of 1st Embodiment, and sectional drawing in the IVB-IVB line | wire. It is a fragmentary sectional view showing a resin sealing process among manufacturing processes of a resin sealing type semiconductor device of a 1st embodiment. (A), (b) is sectional drawing and the back view in the VIA-VIA line | wire which show the structure after the resin sealing process of the resin sealing type semiconductor device of 1st Embodiment after completion | finish. (A), (b) is a top view of a lead frame concerning a 2nd embodiment of the present invention, and a sectional view in IIB-VIIB line, respectively, in order. (A), (b) is the plane which shows the process of upsetting the center part of a die pad and mounting a lead frame on a sealing sheet among the manufacturing processes of the resin-encapsulated semiconductor device of the second embodiment. It is sectional drawing in a figure and a VIIIB-VIIIB line. (A), (b) is the top view which shows the process of dividing a lead among the manufacturing processes of the resin-encapsulated semiconductor device of 2nd Embodiment, and sectional drawing in the IXB-IXB line | wire. (A), (b) is sectional drawing and the back view in the XA-XA line | wire which show the structure after completion | finish of the resin sealing process of the resin sealing type semiconductor device of 2nd Embodiment. (A), (b) is the top view of the lead frame which concerns on the modification of the 2nd Embodiment of this invention, respectively, and sectional drawing in a XIB-XIB line | wire, respectively. It is a figure which shows the structure of the lead frame used for the conventional resin-encapsulated semiconductor device.

Explanation of symbols

100, 200 Outer frame 101, 201 Die pad 101a, 201a Protruding part 201b Radiation terminal 201c Thin film part 102, 202 Lead 103, 203 Reinforcing land 104, 204 Island part 104a, 204a Bonding pad 104b, 204b Land electrode (external terminal)
105,205 Connecting portion 150,250 Sealing sheet 160,260 Semiconductor chip 170,270 Metal fine wire (connection member)
180a Upper mold 180b Lower mold 190,290 Sealing resin

Claims (13)

An outer frame that encloses an area for mounting a semiconductor chip by a plurality of sides;
A die pad for mounting the semiconductor chip;
The upper surface is a bonding pad for connecting a thin metal wire and the lowermost portion is an external terminal, and the lower portion is lacking so as to be thinner than the island portion, and between the outer frame and the island portion, A plurality of leads each having a plurality of connecting portions connecting between the island portions and between the island portion and the die pad;
A land formed at a corner of the outer frame, connected to the outer frame via the connecting portion, and having a larger area than the island;
The lead frame, wherein the die pad and the outer frame are connected via the connecting portion and the island portion, avoiding being directly connected by suspension leads. The lead frame according to claim 1, wherein
The lowermost part of each said island part has the substantially same planar shape, and is arrange | positioned at the grid | lattice form. The lead frame according to claim 1 or 2,
The lowermost portion of each island is a lead frame arranged in a plurality of rows of three or more along each side of the outer frame. The lead frame according to any one of claims 1 to 3,
The lead frame includes a lead connected to another lead connected to another side adjacent to one side of the outer frame to which the lead is connected.   The lead frame according to claim 1, wherein
  The die pad has a thin film portion that is provided along the outer peripheral portion of the main body portion and lacks a lower portion, and a plurality of heat dissipation terminals that protrude downward from the lower surface of the thin film portion,
  The lead part, wherein the island part and the die pad are connected by connecting the island part and the heat dissipating terminal by the connecting part. Die pad,
A semiconductor chip mounted on the die pad;
It is separated from the die pad, the upper surface is a bonding pad for connecting a thin metal wire, and the lowermost part is an island that is an external terminal,
A plurality of connecting members for connecting each part of the semiconductor chip and the bonding pads to each other;
A land formed in a corner portion and having a larger area than the island portion,
Sealing resin for sealing the semiconductor chip, the connecting member, the island part, the land, and the die pad in a state where the lowermost part of the island part and the land and at least a part of the bottom surface of the die pad are exposed. And
A resin-encapsulated semiconductor device in which a member extending from the die pad and having a tip exposed on the surface of the encapsulating resin is not provided. The resin-encapsulated semiconductor device according to claim 6 ,
Each of the external terminals has a substantially same planar shape, and is arranged in a grid pattern on the back surface of the sealing resin. The resin-encapsulated semiconductor device according to claim 6 or 7 ,
Each of the external terminals is a resin-encapsulated semiconductor device arranged in a plurality of rows of three or more on the back surface of the sealing resin along the outer periphery.   The resin-encapsulated semiconductor device according to claim 6,
  The die pad is a resin-encapsulated semiconductor device having a thin film portion provided along the outer peripheral portion of the main body portion and lacking a lower portion, and a plurality of heat radiating terminals protruding downward from the lower surface of the thin film portion. An outer frame surrounding a region for mounting a semiconductor chip by a plurality of sides, a die pad for mounting the semiconductor chip, an island portion whose upper surface is a bonding pad for connecting a thin metal wire, and whose lowermost portion is an external terminal; A plurality of portions, each having a lower portion so as to be thinner than the island, and connecting the outer frame and the island, between the islands, and between the island and the die pad. A plurality of leads having a connecting portion; and a land formed at a corner portion of the outer frame, connected to the outer frame through the connecting portion, and having a larger area than the island portion, The step (a) of preparing the lead frame connected to the island portion and the connecting portion by avoiding the die pad and the outer frame being directly connected by the suspension lead;
A step (b) of mounting a semiconductor chip on the die pad of the lead frame;
Before or after the step (b), the step (c) of placing the lead frame on a sealing sheet having an adhesive force;
After the step (c), in a state where the lead frame is placed on the sealing sheet, the step of cutting the connecting portions to separate the island portion and the die pad from the outer frame;
After the step (d), a step (e) of connecting a part of the semiconductor chip and the bonding pad by a connecting member;
After the step (e), a method of manufacturing a resin-encapsulated semiconductor device, including a step (f) of resin-sealing in a state where the lead frame is placed on the sealing sheet. In the manufacturing method of the resin-sealed semiconductor device according to claim 10 ,
After the step (f), there is no member that is connected to the die pad and whose tip is exposed on the surface of the sealing resin. In the manufacturing method of the resin-sealed semiconductor device according to claim 10 or 11 ,
The plurality of leads of the lead frame prepared in the step (a) are connected to other leads connected to other sides adjacent to one side of the outer frame to which the leads are connected. A method for manufacturing a resin-encapsulated semiconductor device including a lead.   In the manufacturing method of the resin-sealed semiconductor device according to claim 10,
  The die pad has a thin film portion that is provided along the outer peripheral portion of the main body portion and lacks a lower portion, and a plurality of heat dissipation terminals that protrude downward from the lower surface of the thin film portion,
  The method of manufacturing a resin-encapsulated semiconductor device, wherein the island part and the die pad are connected by connecting the island part and the heat radiating terminal by the connecting part.

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