JP2005079181A - Lead frame, resin-sealed semiconductor device using the same, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the separation of die pad from a sealing resin material caused by the application of thermal stress simply by changing the shape of the die pad, and to suppress the progress of a separation region even if the separation occurs. <P>SOLUTION: A resin-sealed semiconductor device comprises the die pad 15, a plurality of suspension leads 16a-16d for retaining the die pad, a plurality of inner leads 12 that are arranged at the periphery of the die pad and are electrically connected to the electrode pad of a semiconductor element mounted onto the die pad, a dam bar 14 formed by connecting the plurality of inner leads laterally, and an outer lead 13 provided for electrical connection with the outside corresponding to the plurality of inner leads. The above elements are supported in a frame. Each periphery of the die pad located between respective suspension leads has a curved shape recessed at the center. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lead frame for configuring a semiconductor device on which a semiconductor element is mounted and resin-sealed, a resin-encapsulated semiconductor device using the lead frame, and a manufacturing method thereof.

  As a conventional resin-encapsulated semiconductor device, one having a structure in which a semiconductor element is mounted on a lead frame and resin-encapsulated is known (see, for example, Patent Document 1). FIG. 11A shows a planar shape of a lead frame 1 for a conventional semiconductor device. The lead frame 1 includes an inner lead 2, an outer lead 3, a dam bar 4, a die pad 5 on which a semiconductor element is mounted, and suspension leads 6a, 6b, 6c, and 6d that support the die pad 5. The die pad 5 is formed in a quadrangular shape, and its four corners are respectively coupled to the suspension leads 6a to 6d.

  FIG. 11B shows a state in which a semiconductor element is mounted on the lead frame 1. FIG. 11B shows a cross section corresponding to the line A-A ′ of FIG. 11A. An adhesive 8 is applied to the upper surface of the die pad 5 and the semiconductor element 7 is bonded. The area of the die pad 5 is smaller than the area of the semiconductor element 7.

  FIG. 11C shows a state where the structure of FIG. 11B is resin-sealed with the sealing resin 10. Here, the suspension leads 6a to 6 are formed so that the resin thickness a from the surface of the semiconductor element 7 mounted on the die pad 5 to the surface of the package is substantially the same as the resin thickness b from the back surface of the die pad 5 to the back surface of the package. Depressing is performed on 6d to form the depressed portion 9, and the die pad 5 is lowered below the inner lead 2.

Next, a method for manufacturing a resin-encapsulated semiconductor device using a conventional lead frame will be described with reference to FIGS. First, the semiconductor element 7 is bonded onto the die pad 5 of the lead frame 1 with an adhesive 8 such as silver (Ag) paste, and is thermally cured and fixed. Next, the electrode pad (not shown) of the mounted semiconductor element 7 and the inner lead 2 of the lead frame 1 are electrically connected by a thin metal wire (not shown). Thereafter, the outer periphery of the semiconductor element 7, the fine metal wires, the die pad 5, and the inner lead 2 are sealed with a sealing resin 10 to form a body portion of the resin-encapsulated semiconductor device. Thereafter, by cutting the dam bar 4 of the lead frame 1 that has served as a resin stopper, the outer leads 3 are electrically separated and independent to complete a resin-encapsulated semiconductor device.
Japanese Patent Laid-Open No. 10-4173

  In the resin-encapsulated semiconductor device having the above-described configuration, package cracks due to thermal stress when mounted on a substrate and repeated thermal stress in an actual operation state are serious problems. As a cause of this problem, separation between the corner portion of the die pad 5 and the sealing resin 10 is caused by a difference in expansion coefficient between the material of the lead frame 1 and the material of the sealing resin 10. This delamination proceeds by the application of thermal stress, and when the delaminations at adjacent corners are close to each other or connected, the remaining residual stress tends to escape to the outside of the package, causing package cracks. To do.

  Further, when the size of the die pad 5 is considerably smaller than that of the semiconductor element 7, the following problem occurs. FIG. 12 is a cross-sectional view showing a problem in a conventional method for manufacturing a resin-encapsulated semiconductor device. Thus, when the size of the die pad 5 is considerably smaller than the semiconductor element 7, it is difficult to obtain sufficient strength for holding the semiconductor element 7 by the die pad 5. Therefore, when the metal thin wire 30 is wire-bonded to the electrode pad 7a on the semiconductor element 7 by the capillary 31, the semiconductor element 7 bends due to the capillary 31 pressing the electrode pad 7a. As a result, in the worst case, the connection failure of the fine metal wire 30 occurs, and the microcrack 43 may occur in the semiconductor element 7.

  On the other hand, conventionally, in order to make it difficult for the lead frame material and the sealing resin material to be peeled off, the die pad is subjected to slit processing or dimple processing to increase the bonding area between the die pad and the sealing resin, or to seal the die pad and the sealing resin material. In order to increase the bonding strength of the resin, special processing such as applying an adhesion reinforcing material to the surface of the lead frame has been performed.

  The present invention suppresses the peeling of the die pad from the sealing resin material due to the application of thermal stress only by changing the shape of the die pad without performing special processing on the die pad or the lead frame. It is an object of the present invention to provide a lead frame that can suppress the progress of the peeled region even if the occurrence of the occurrence of the occurrence of the occurrence of the peeling region, and a resin-encapsulated semiconductor device using the lead frame.

  Another object of the present invention is to obtain sufficient strength for holding a semiconductor element by a die pad.

  A lead frame having a first configuration according to the present invention is mounted on a die pad, arranged on a peripheral portion of the die pad, a die pad for mounting a semiconductor element, a plurality of suspension leads for holding the die pad, and the die pad. A plurality of inner leads electrically connected to the electrode pads of the semiconductor element, a dam bar formed by connecting the plurality of inner leads in a lateral direction, and the plurality of inner leads, respectively. It has an outer lead provided for electrical connection with the outside, and has a basic structure in which the above elements are supported in a frame. Each of the peripheral edges of the die pad positioned between the suspension leads has a curved shape that is recessed at the center.

  The lead frame of the second configuration of the present invention has the same basic structure as described above, and four suspension leads are provided, and each peripheral edge of the four sides of the die pad located between the suspension leads is a center. It has an obtuse V-shape that is recessed at the portion, and the vertex of the V-shape is substantially located at the center of each peripheral edge.

  The lead frame of the third configuration of the present invention has the same basic structure as described above, and four suspension leads are provided, and each peripheral edge of the die pad located between the suspension leads is connected to the suspension leads. It has a straight line part corresponding to each side of the quadrangle in the adjacent part, and has a depressed shape between the straight line parts.

  The resin-encapsulated semiconductor device of the present invention is arranged on a die pad, a plurality of suspended leads that hold the die pad, a semiconductor element that is larger than the die pad mounted on the die pad, and a peripheral portion of the die pad. A plurality of inner leads electrically connected to the electrode pads of the semiconductor element, outer leads provided for electrical connection to the outside corresponding to the plurality of inner leads, and the outer leads And a sealing resin that seals other elements. The die pad has the same configuration as the die pad in the lead frame having any one of the first to third configurations.

  A method for manufacturing a resin-encapsulated semiconductor device according to the present invention uses a lead frame having any one of the above-described structures, and a semiconductor element is fixed on the die pad of the lead frame with an adhesive, and the electrode pad of the semiconductor element and the inner In this manufacturing method, the lead is electrically connected, the outer lead is exposed, and other elements are sealed with a sealing resin. Then, when the semiconductor element is fixed to the die pad with an adhesive, the application amount of the adhesive is adjusted so that the adhesive slightly protrudes around the die pad from between the semiconductor element and the die pad. And

  In the resin-encapsulated semiconductor device configured using the lead frame configured as described above, the die pad has a shape that can relieve stress caused by expansion and contraction due to thermal stress after resin encapsulation. Therefore, the die pad or lead frame can be prevented from being peeled off due to thermal stress without special processing, and the progress of the peeled area can be suppressed even if peeling occurs.

  Further, according to the method of manufacturing the resin-encapsulated semiconductor device having the above-described configuration, the semiconductor element is fixed by combining the lead frame having the above-described configuration and adjustment of the amount of adhesive applied to fix the semiconductor element. Thus, the spread and strength of the adhesive necessary for the process can be secured, and the occurrence of package cracks can be suppressed.

  In the lead frame of the first configuration of the present invention, preferably, the periphery of the die pad forms a parabolic curve and is smoothly connected to the side edge of the adjacent suspension lead.

  In the lead frame of the second configuration of the present invention, preferably, the apex portion in the V shape of each peripheral edge of the die pad is formed in a smooth curved shape.

  In the lead frame of the third configuration of the present invention, preferably, each peripheral edge of the die pad has a V shape between the straight portions. Preferably, each peripheral edge of the die pad is formed in an arc shape between the linear portions, and the arc-shaped central portion and the linear portion are connected by a smooth curve. Further preferably, the length of the straight line portion is set within a range of 20% to 40% of the length of the peripheral edge portion of one side of the die pad.

  In the method for manufacturing a resin-encapsulated semiconductor device of the present invention, preferably, the adhesive has a thickness of 10 μm to 30 μm, and is solidified so as to blow up from the top surface of the die pad to the back surface of the semiconductor element in a cross-sectional shape.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view showing a lead frame 11 according to Embodiment 1 of the present invention. In the lead frame 11, a plurality of unit structures for constituting one semiconductor device having an inner lead 12 surrounding the die pad 15 and an outer lead 13 are arranged vertically and horizontally. A round hole 11a around the semiconductor device in the figure is a part for dropping a runner portion that becomes a resin passage when resin-sealing after resin sealing, and round holes 11b and oblong holes existing above and below the lead frame 11. 11c is used for conveyance and positioning of the lead frame 11. The unit structure in the lead frame 11 is shown in an enlarged manner in FIG. 2A.

  FIG. 2A is a plan view showing a unit structure of the lead frame 11. This unit structure includes an inner lead 12, an outer lead 13, a dam bar 14, a die pad 15, and suspension leads 16a, 16b, 16c, and 16d that support the die pad 15. The die pad 15 is the same as or smaller than the size of the semiconductor element to be mounted. The periphery of the die pad 15 has a parabolic curved shape that is recessed at the center, and is smoothly connected to the side edges of the adjacent suspension leads 16a to 16d. The peripheral shape of the die pad 15 is not limited to a parabolic shape, and other curved shapes may be adopted.

  A state in which a semiconductor element is mounted on the lead frame 11 is shown in FIG. 2B. 2B is a cross-sectional view at a position corresponding to the line B-B ′ of FIG. 2A. As shown in the figure, the semiconductor element 17 is fixed on the die pad 15 with an adhesive 18 such as silver (Ag) paste. An electrode pad (not shown) of the mounted semiconductor element 17 and the inner lead 12 (see FIG. 2A) are electrically connected by a thin metal wire.

  FIG. 2C shows a state where the structure of FIG. 2B is resin-sealed with the sealing resin 20. At the time of resin sealing, the dam bar 14 (see FIG. 2A) is limited to the area of the outer periphery of the semiconductor element 17, the fine metal wire, the die pad 15, and the inner lead 12 disposed inside the dam bar 14. It serves as a resin stopper for forming the body portion of the semiconductor device.

  A depressed portion 19 is formed on the suspension leads 16a, 16b, 16c, and 16d by a depression process. The depressed portion 19 is positioned lower than the inner lead 12 on the die pad 15, and the resin thickness (amount) from the surface of the semiconductor element 17 mounted on the die pad 15 to the surface of the package, and the back surface of the die pad 15 to the back surface of the package. The resin thickness (amount) up to approximately the same.

  The displacement amount by the depressed portion 19, that is, the depressed amount is just a good calculation when the amount is half the thickness of the semiconductor element 17. However, in practice, it is necessary to take into consideration that the fluidity of the sealing resin 20 changes depending on the number of thin metal wires connected and the size of the semiconductor element 17 mounted on the die pad 15. If the setting of the depression amount is not appropriate, the chip position varies depending on the resin flow, and as a result, exposure of fine metal wires and resin voids (nests, unfilled portions) occur. From the experimental results, it has been found that when the lead frame 11 of the present embodiment is used, a TQFP (Thin Qaud Flat Package) having a body thickness of 1.00 mm requires a pressing amount equivalent to the thickness of the semiconductor element 17. doing.

  On the surface of the lead frame 11, for example, a three-layer plating layer including a nickel (Ni) plating layer, a palladium (Pd) plating layer, and a gold (Au) plating layer is formed, or tin-silver (Sn) is formed. -Ag), tin-bismuth (Sn-Bi) or the like is partially subjected to solder plating. The plating thickness is 1 μm or less for Au plating and Pd plating, and several μm or less for Ag plating.

  Next, a method for manufacturing a resin-encapsulated semiconductor device using the lead frame 11 having the above configuration will be described with reference to FIGS. FIGS. 3-1 (a) and (b) are plan views showing steps of a method for manufacturing a resin-encapsulated semiconductor device, and FIGS. 3-1 (c) and FIGS. 3-2 (d) to (f) are diagrams. It is sectional drawing in the position corresponding to CC 'line in 3-1 (b).

  First, although not shown, as a pre-process, in a dicing process in which a semiconductor wafer on which a plurality of semiconductor elements 17 are formed is divided into individual semiconductor elements 17, the semiconductor wafer is attached to an adhesive sheet and diced. The adhesive of the adhesive sheet remaining on the back surface of each separated semiconductor element 17 is cleaned with ultraviolet rays (UV) to keep the back surface of the semiconductor element 17 clean. Ultraviolet (UV) cleaning is performed by irradiating the back surface of the semiconductor element 17 with ultraviolet rays, and is effective when an ultraviolet curable adhesive is used for the adhesive sheet during dicing. When other pressure-sensitive adhesives are used, appropriate cleaning is performed as appropriate.

  Further, as shown in FIG. 3A, a lead frame 11 similar to that shown in FIGS. 1 and 2A is prepared. Then, as shown in FIGS. 3-1 (b) and (c), the semiconductor element 17 whose back surface is cleaned by the previous process is formed on the die pad 15 of the lead frame 11 by a die bonding process, such as a silver (Ag) paste. Temporary joining is performed with the adhesive 18, and the resin is thermally cured at 100 to 250 ° C. and completely fixed. The amount of the adhesive 18 applied to the die pad 15 is adjusted so that the adhesive slightly protrudes from the periphery of the die pad 15 from between the semiconductor element 17 and the die pad 15. The thickness of the adhesive 18 is 10 μm to 30 μm, and the cross-sectional shape is solidified so as to be blown up from the upper surface of the die pad 15 to the back surface of the semiconductor element 17.

  Next, the electrode pads of the mounted semiconductor element 17 and the inner leads 12 of the lead frame 11 are electrically connected (wire bonding) with the fine metal wires 30. As the metal thin wire 30, for example, a wire having a diameter of 15 to 30 μm made of gold (Au) having a purity of 99.99% or more is used and bonded by an ultrasonic / thermocompression method using a wire bonder. Although not shown in the ultrasonic / thermocompression bonding process, the metal wire 30 is passed through the capillary tool while heating the lead frame 11 on a heater plate at 150 ° C. to 250 ° C. Ultrasonic vibration and a load are applied, and a metal ball formed in advance is pressed and joined to the electrode pad side of the semiconductor element 17, then moved to the inner lead 12 side, and the fine metal wire is pressed and broken with a capillary tool. At this time, the movement of the capillary tool is controlled on the wire bonder side so that the thin metal wire 30 has an arbitrary loop shape (loop height).

  Thereafter, as shown in FIGS. 3-2 (d) and (e), the outer periphery of the semiconductor element 17, the metal thin wires 30, and the regions of the inner leads 12 are sealed with the sealing resin 20, and FIG. As shown in FIG. 2, the body portion of the resin-encapsulated semiconductor device is formed. That is, first, as shown in FIG. 3D, an upper sealing die 37 and a lower sealing die 38 for forming the body of the resin-encapsulated semiconductor device are prepared. Then, a lead frame on which the semiconductor element 17 is mounted is loaded and sandwiched in a cavity 39 formed by the upper sealing mold 37 and the lower sealing mold 38. Further, a tablet-shaped thermosetting sealing resin 20 (epoxy resin) is put into a pot 33 adjacent to the upper sealing mold 37 and the lower sealing mold 38 and pushed in by the plunger 32. The pressed sealing resin 20 (epoxy resin) is melted into liquid by the heat of the pot 33, the plunger 32, and the upper and lower sealing molds 37 and 38 that have been heated to 150 to 200 ° C., and passes through the runner 34. Then, it is injected from the gate 35 into the cavity 39 (see FIG. 3-2 (e)). On the opposite side of the gate 35, an air bend 36 is provided for exhausting the injection of the sealing resin 20.

  Finally, as shown in FIG. 3-2 (f), the dam bar 14 (see FIG. 3-1 (a)) of the lead frame 11 that has served as a resin stopper is cut with a die like a skewer. To do. As a result, the outer leads 13 of the lead frame 11 which are electrically separated and independent are molded into a gull wing shape. The two-step shape of the outer lead 13 shown in FIG. 3-2 (f) is called a gull wing, and this resin-encapsulated semiconductor device is called a P-QFP (Plastic Qaud Flat Package) or the like.

  Note that, as described above, in order to make the sealing resin thickness on the semiconductor element 17 and the sealing resin thickness below the die pad 15 the same size, depending on the size and shape of the die pad 15, the depressed portion 19. It is necessary to change the height.

  As described above, the periphery of the die pad 15 having the same or smaller outer shape as that of the semiconductor element 17 has a parabolic curved shape, and is smoothly connected to the side edges of the adjacent suspension leads 16a to 16d. Even when stress and shrinkage stress at low temperature are applied, the stress generated in the holding portion of the die pad 15 by the suspension leads 16a to 16d can be dispersed. Thereby, generation | occurrence | production of peeling of the die pad 15 from the sealing resin 20 resulting from thermal stress is suppressed, generation | occurrence | production of the package crack which develops from progress of peeling can be prevented, and reliability can be ensured. This effect was confirmed by a comparative experiment with a resin-encapsulated semiconductor device of a conventional example.

  4 (a) and 4 (b) show the results of conducting a comparative test on the conventional example and the resin-encapsulated semiconductor device which is an example of the present invention and observing the progress of peeling. 4A shows the case where the conventional lead frame 1 shown in FIG. 11A is used, and FIG. 4B shows the case where the lead frame 11 of the embodiment of the present invention shown in FIG. 2A is used. . FIG. 4 shows only the peeled state at the final point of the comparative experiment.

  Each was tested under the same conditions, and a temperature cycle test was adopted as a test method. The condition was -65 ° C (5 minutes) to 150 ° C (5 minutes) as one cycle, and the progress of peeling was confirmed while repeating this cycle. The observation was performed on the peeling state of the bonding with the sealing resin on the back surface of the die pad, and an ultrasonic probe (SAT) was used for the observation.

  In the case of the conventional example, as shown in FIG. 4A, the peeling progressed until the peeling region 40 extended over the entire peripheral portion of the die pad 5, and the adhesion region 41 was only left at the center. In contrast, in one embodiment of the present invention, it was observed that the peeling region 40 was stopped in a partial region of the peripheral edge of the die pad 15 as shown in FIG.

  The important point here is that the defect rate of the resin-encapsulated semiconductor device becomes conspicuous when the peeling region 40 advances to the entire peripheral portion of the die pad 5 as in the conventional example shown in FIG. As an example of the failure mode, when the peeling region 40 absorbs moisture and heat is applied, moisture is vaporized and evaporated, so that package cracks may occur due to escape to the outside of the package. As long as the separation region 40 stops at a part of the peripheral region of the die pad 15 as in the case of the present invention shown in FIG. 4B, the reliability is not greatly affected.

  FIG. 5 shows a mechanism of peeling progress in the test of the resin-encapsulated semiconductor device in one embodiment of the present invention. 5 (a) and 5 (b) show a state in the middle of the comparative experiment and a state at the final time point, respectively. FIG. 5C shows a part where the die pad 15 is peeled from the sealing resin 20 in a cross section taken along the line D-D ′ in FIG. With the progress of the temperature cycle test, as shown in FIG. 5A, a stress due to a temperature difference acts on the resin-encapsulated semiconductor device, and the separation region 40 is formed from the back surfaces of the suspension leads 16a to 16d. However, as shown in FIG. 5B, the progress of peeling stops in the vicinity of the holding portion by the suspension leads 16a to 16d on the peripheral portion of the die pad 15. This is considered that the curved shape of the periphery of the die pad 15 plays a role of stopping the progress of peeling.

  Further, according to the present embodiment, even when the size of the die pad 15 is considerably smaller than the size of the semiconductor element 17, the shape of the die pad 15 having a curved peripheral edge causes the semiconductor element 17 to be formed by the die pad 15. Holding is stable.

(Embodiment 2)
The lead frame in the second embodiment will be described with reference to FIGS. 6 to 9 are plan views showing examples of a lead frame having a die pad having a shape different from that of the die pad 15 of the lead frame 11 shown in FIG. The structure of other parts is the same as that shown in FIG. The shape as shown in FIGS. 6 to 9 is adopted when it is difficult to process into a shape constituted by a curve like the die pad shape 15 of the lead frame shown in FIG. 1 or when a semiconductor element to be mounted is large. . Thereby, an effect close to that of the shape shown in FIG. 1 can be obtained.

  The lead frame 21a shown in FIG. 6 linearly surrounds the periphery of the die pad 22a formed between the suspension leads 16a and 16b, between the suspension leads 16b and 16c, between the suspension leads 16c and 16d, and between the suspension leads 16d and 16a. Formed. That is, the parabolic curved shape shown in FIG. 2A is replaced with a straight line, and a V-shape that is recessed at the center of the die pad 22a is formed. The vertex of the V shape is positioned substantially in the center.

  The lead frame 21b shown in FIG. 7 is also formed by linearly forming the periphery of the die pad 22b formed between the suspension leads 16a to 16d. That is, the four corner portions adjacent to the suspension leads 16a to 16d are formed by straight lines corresponding to the sides of the quadrangle. The portion between the four corners is also linear, and has a V shape that is recessed at the center.

  In the lead frame 21c shown in FIG. 8, the four corners adjacent to the suspension leads 16a to 16d on the periphery of the die pad 22b are formed by straight lines corresponding to the sides of the quadrangle as in the case of FIG. A portion between the four corners is formed in an arc shape, and the straight portions at the four corners are connected by smooth curves.

  The lead frame 21d shown in FIG. 9 is formed by forming the four corner portions adjacent to the suspension leads 16a to 16d on the periphery of the die pad 22b by straight lines corresponding to the sides of the quadrangle as in the case of FIG. The part between the four corners is also straight and recessed in a trapezoidal shape.

  In the above configuration, the length of the straight line portions at the four corners is set within a range of 20% to 40% of the length of the peripheral edge portion of one side of the die pad.

(Embodiment 3)
With reference to FIG. 10, the resin-encapsulated semiconductor device in the third embodiment will be described. The present embodiment is an example in which the present invention is applied to a resin-encapsulated semiconductor device called P-QFN (Plastic Qaud Flat Non-leaded Package).

  FIG. 10A is a plan view showing the lead frame 23 in the present embodiment. The lead frame 23 is different from the structure of the lead frame in the above-described embodiment in that the frame 24 also serves as a dam bar, and the lead 25 also serves as an inner lead and an outer lead. Further, an upset portion 27 is formed on the suspension leads 26a, 26b, 26c, and 26d by press working. Since the other parts are the same, the same reference numerals are given, and repeated description is omitted. The die pad 15 is set smaller than the semiconductor element as in the above-described embodiment.

  As shown in FIG. 10 (c), the lead 25 disposed on the periphery of the die pad 15 is electrically connected to the semiconductor element 17 and the metal thin wire 30 at the inner lead portion 25 a which is the upper surface thereof. The lower surface of the lead 25 is used as an outer lead portion 25b for electrical connection with the outside.

  Next, a manufacturing process of the resin-encapsulated semiconductor device using the lead frame 23 shown in FIG.

  As shown in FIGS. 10B and 10C, in the die bonding step, the semiconductor element 17 is temporarily bonded to the die pad 15 with an adhesive 18 such as a silver (Ag) paste and thermally cured at 100 to 250 ° C. In the wire bonding step, an electrode pad (not shown) of the mounted semiconductor element 17 and the inner lead portion 25a are electrically connected (wire bonding) with the thin metal wire 30.

  Next, as shown in FIG. 10C, the die pad 15, the semiconductor element 17, the fine metal wire 30, and the lead 25 are sealed with a sealing resin 20. At this time, the outer lead portion 25 b on the lower surface of the lead 25 is exposed on the bottom surface of the sealing resin 20. After sealing, the frame 24 serving as a dam bar is separated by dicing, and the leads 25 are electrically separated and independent.

  Thus, it goes without saying that the same effect as described above can be obtained even when the die pad shape in the embodiment of the present invention is applied to a P-QFN (Plastic Qaud Flat Non-leaded Package) shown in FIG.

  According to the present invention, by changing the shape of the die pad without applying special processing to the die pad or the lead frame, it is possible to suppress the peeling of the die pad that occurs due to the application of thermal stress. Therefore, it can be effectively applied to the manufacture of a resin-encapsulated semiconductor device.

The top view which shows the lead frame in Embodiment 1 of this invention A plan view showing an enlarged part of the lead frame Sectional drawing which shows the state before sealing of the resin sealing type semiconductor device in Embodiment 1 Sectional drawing which shows the state after the sealing The process of the manufacturing method of the resin sealing type semiconductor device in Embodiment 1 is shown, (a) And (b) is a top view, (c) is sectional drawing. Sectional drawing which shows the process following FIGS. Observation view showing test results of resin-encapsulated semiconductor device in conventional example and embodiment 1 The mechanism of the peeling progress in the test of the resin-encapsulated semiconductor device in Embodiment 1 is shown, (a) and (b) are plan views, and (c) is a sectional view. FIG. 5 is a plan view showing an example of a lead frame in the second embodiment Plan view showing a lead frame of another example Plan view showing a lead frame of another example Plan view showing a lead frame of another example 4 shows a resin-encapsulated semiconductor device in Embodiment 3, wherein (a) is a plan view of a lead frame, (b) is a plan view showing a state in which a semiconductor element is mounted on the lead frame, and (c) is a resin-encapsulated state. Sectional view of a type semiconductor device Plan view showing a conventional lead frame Sectional drawing which shows the state before sealing of the resin-sealed semiconductor device of a prior art example Sectional drawing which shows the state after the sealing Sectional drawing which shows the subject in the manufacturing method of the resin-sealed semiconductor device of a prior art example

Explanation of symbols

1, 11, 21a to 21d, 23 Lead frame 2, 12 Inner lead 3, 13 Outer lead 4, 14 Dam bar 5, 15, 22a to 22d Die pads 6a to 6d, 16a to 16d, 26a to 26d Hanging lead 7, 17 Semiconductor Element 7a Electrode pad 8, 18 Adhesive 9, 19 Depressing part 10, 20 Sealing resin 11a, 11b Round hole 11c Long hole 24 Frame 25 Lead 27 Upset part 30 Metal wire 31 Capillary 32 Plunger 33 Pot 34 Runner 35 Gate 36 Air bend 37 Upper sealing die 38 Lower sealing die 39 Cavity 40 Peeling region 41 Adhering region 42 Deflection amount 43 Microcrack

Claims (13)

A die pad for mounting a semiconductor element, a plurality of suspension leads for holding the die pad, and arranged around the die pad and electrically connected to an electrode pad of the semiconductor element mounted on the die pad. A plurality of inner leads, a dam bar formed by laterally connecting the plurality of inner leads, and an outer provided for electrical connection to the outside corresponding to the plurality of inner leads, respectively. In a lead frame that includes a lead and the above elements are supported in the frame,
The lead frame according to claim 1, wherein each of the peripheral edges of the die pad located between the suspension leads has a curved shape that is recessed at the center.   The lead frame according to claim 1, wherein a peripheral edge of the die pad forms a parabolic curve and is smoothly connected to a side edge of an adjacent suspension lead. A die pad for mounting a semiconductor element, a plurality of suspension leads for holding the die pad, and arranged around the die pad and electrically connected to an electrode pad of the semiconductor element mounted on the die pad. A plurality of inner leads, a dam bar formed by laterally connecting the plurality of inner leads, and an outer provided for electrical connection to the outside corresponding to the plurality of inner leads, respectively. In a lead frame that includes a lead and the above elements are supported in the frame,
Four suspension leads are provided, and each peripheral edge of the four sides of the die pad located between the suspension leads has an obtuse V-shape recessed at the center, and the vertex of the V-shape is substantially A lead frame characterized by being located at the center of each peripheral edge.   The lead frame according to claim 3, wherein apexes in the V-shape of each peripheral edge of the die pad are formed in a smooth curved shape. A die pad for mounting a semiconductor element, a plurality of suspension leads for holding the die pad, and arranged around the die pad and electrically connected to an electrode pad of the semiconductor element mounted on the die pad. A plurality of inner leads, a dam bar formed by laterally connecting the plurality of inner leads, and an outer provided for electrical connection to the outside corresponding to the plurality of inner leads, respectively. In a lead frame that includes a lead and the above elements are supported in the frame,
Four suspension leads are provided, and each peripheral edge of the die pad located between the suspension leads has a linear portion corresponding to each side of the quadrangle at a portion adjacent to the suspension lead, A lead frame characterized by having a recessed shape between them.   The lead frame according to claim 5, wherein each peripheral edge of the die pad has a V shape between the straight portions.   6. The lead frame according to claim 5, wherein each edge of the die pad is formed in an arc shape between the linear portions, and the arc-shaped central portion and the linear portion are connected by a smooth curve.   6. The lead frame according to claim 5, wherein the length of the straight line portion is set within a range of 20% to 40% of the length of the peripheral edge portion of one side of the die pad. A die pad, a plurality of suspended leads for holding the die pad, a semiconductor element larger than the die pad mounted on the die pad, and arranged in a peripheral portion of the die pad, and electrically connected to the electrode pad of the semiconductor element A plurality of connected inner leads, an outer lead provided for electrical connection to the outside corresponding to each of the plurality of inner leads, and the outer leads exposed to seal other elements In a resin-encapsulated semiconductor device provided with an encapsulating resin,
The resin-encapsulated semiconductor device according to claim 1, wherein each of the peripheral edges of the die pad located between the suspension leads has a curved shape that is recessed at the center. A die pad, a plurality of suspended leads for holding the die pad, a semiconductor element larger than the die pad mounted on the die pad, and arranged in a peripheral portion of the die pad, and electrically connected to the electrode pad of the semiconductor element A plurality of connected inner leads, an outer lead provided for electrical connection to the outside corresponding to each of the plurality of inner leads, and the outer leads exposed to seal other elements In a resin-encapsulated semiconductor device provided with an encapsulating resin,
Four suspension leads are provided, and each peripheral edge of the four sides of the die pad located between the suspension leads has an obtuse V-shape recessed at the center, and the vertex of the V-shape is substantially A lead frame characterized by being located at the center of each peripheral edge. A die pad, a plurality of suspended leads for holding the die pad, a semiconductor element larger than the die pad mounted on the die pad, and arranged in a peripheral portion of the die pad, and electrically connected to the electrode pad of the semiconductor element A plurality of connected inner leads, an outer lead provided for electrical connection to the outside corresponding to each of the plurality of inner leads, and the outer leads exposed to seal other elements In a resin-encapsulated semiconductor device provided with an encapsulating resin,
Four suspension leads are provided, and each peripheral edge of the die pad located between the suspension leads has a linear portion corresponding to each side of the quadrangle at a portion adjacent to the suspension lead, A resin-encapsulated semiconductor device characterized by having a recessed shape between. 9. The lead frame according to claim 1, wherein a semiconductor element is fixed on a die pad of the lead frame with an adhesive, and the electrode pad of the semiconductor element and the inner lead are electrically connected. In the method of manufacturing a resin-encapsulated semiconductor device in which the outer lead is exposed and other elements are encapsulated with an encapsulating resin,
When the semiconductor element is fixed to the die pad with an adhesive, the amount of the adhesive applied is adjusted so that the adhesive slightly protrudes around the die pad from between the semiconductor element and the die pad. Manufacturing method of resin-encapsulated semiconductor device.   12. The method of manufacturing a resin-encapsulated semiconductor device according to claim 11, wherein the adhesive has a thickness of 10 to 30 [mu] m and is solidified so as to blow up from the top surface of the die pad to the back surface of the semiconductor element in a cross-sectional shape.

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