Semiconductor device manufacturing method

Abstract

To provide a semiconductor device manufacturing method that can suppress the occurrence of resin burrs on an inner lead portion exposed from a sealing resin portion and / or can suppress peeling of the inner lead portion from the sealing resin portion.SOLUTION: A semiconductor device manufacturing method in which a lead frame 2 on which a semiconductor element 1 is mounted is sandwiched between a first mold 4A and a second mold 4B, and pressing forces including a first pressing force applied from a mold clamping portion 6A of the first mold 4A to a clamped portion 2c of the lead frame 2 in a direction following the shape of a side wall portion 5a of a cavity 5 and a second pressing force applied in a direction inclined opposite to the cavity 5 are applied, generating stress in a direction that causes an inner lead portion 2b of the lead frame 2 to move toward the second mold 4B, thereby clamping the mold, and resin is injected into the cavity 5 to form a sealing resin portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a semiconductor device in which a part of an inner lead portion is exposed from a sealing resin portion. [Background technology]

[0002] As electronic devices incorporating semiconductor devices become smaller and lighter, there is a demand for smaller and lighter semiconductor devices. In semiconductor devices using lead frames, the upper surface of the lead frame on which the semiconductor element is mounted is sealed with resin, and a single-sided sealing structure is used in which the lower surface of the lead frame is exposed through the sealing resin portion, thereby achieving smaller and lighter semiconductor devices.

[0003] 8 is a diagram illustrating a typical method for manufacturing a semiconductor device, and is a cross-sectional view showing a state in which a lead frame is clamped. As shown in Fig. 8, to form a sealing resin portion, a semiconductor element 1 is mounted on a die pad portion 2a, and a lead frame 2 having electrodes of the semiconductor element 1 and inner lead portions 2b connected by metal wires 3 is placed in contact with a mold 4b, and the lead frame 2 is clamped between a pair of molds 4a and 4b. Thereafter, a resin is injected into a cavity 5 to form the sealing resin portion (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-96688 Summary of the Invention [Problem to be solved by the invention]

[0005] When the lead frame 2 is clamped in this manner, the lead frame 2 in the cavity 5 may be deformed so as to lift up from the mold 4b. FIG. 9 is a cross-sectional schematic diagram illustrating deformation of the clamped lead frame shown in FIG. 8. When the lead frame 2 is clamped between the mold 4a having the cavity 5 and the flat mold 4b, a pressing force is applied from the clamping portion 6 of the mold 4a to the clamped portion 2c of the lead frame 2. This pressing force includes a pressing force applied to the clamped portion 2c in a direction perpendicular to the upper surface of the clamped portion 2c, as indicated by arrow A, and a pressing force applied to the clamped portion 2c in a direction following the shape of the side wall portion 5a of the cavity 5, as indicated by arrow B. When these pressing forces are applied to the clamped portion 2c from the clamping portion 6, stress is generated in the lead frame 2, causing the inner lead portion 2b of the lead frame 2 extending from the clamped portion 2c into the cavity 5 to deform in a direction away from the mold 4b.

[0006] Fig. 10 is a cross-sectional view showing a semiconductor device in which the lead frame shown in Fig. 9 is resin-sealed. As explained in Fig. 9, if the inner lead portion 2b of the lead frame 2, which is arranged to abut against the mold 4b, is deformed and the tip of the inner lead portion 2b is separated from the mold 4b when resin is injected into the cavity 5, a sealing resin portion 7 is formed and a thin resin burr 8 occurs on the underside of the inner lead portion 2b, as shown in Fig. 10.

[0007] Furthermore, because the deformation caused by mold clamping is elastic, when the lead frame 2 is released from the mold, the lead frame 2 tries to return to its original shape. This means that the inner lead portion 2b deforms in a direction away from the sealing resin portion 7, or the stress that tries to deform it remains, and if the shear stress between the inner lead portion 2b and the sealing resin portion 7 becomes greater than the adhesive force, the inner lead portion 2b will peel off from the sealing resin portion 7.

[0008] 9, deformation of the lead frame 2 occurs not only in the inner lead portion 2b but also in the inner lead portion connected to the die pad portion 2a. When the inner lead portion 2b arranged to abut against the mold 4b and the inner lead portion connected to the die pad portion 2a are deformed in this way, the resin is injected with the inner lead portion 2b etc. separated from the mold 4b, resulting in the problem of resin burrs 8 occurring on the undersides of the inner lead portion 2b etc. Furthermore, when the lead frame 2 is released from the mold, the inner lead portion 2b etc. peels off from the sealing resin portion 7.

[0009] Therefore, the present invention aims to provide a method for manufacturing a semiconductor device that can suppress the occurrence of resin burrs on the inner lead portion exposed from the sealing resin portion and / or suppress peeling of the inner lead portion from the sealing resin portion. [Means for solving the problem]

[0010] The method for manufacturing a semiconductor device of the present invention is a method for manufacturing a semiconductor device in which a lead frame mounted with a semiconductor element is clamped between a pair of molds and clamped, and resin is injected into the cavity to form a sealing resin portion, and includes a mold clamping process in which a clamped portion of one of the pair of molds applies a pressing force including a first pressing force applied in a direction following the shape of the side wall portion of the cavity and a second pressing force applied in a direction inclined opposite to the cavity to cause stress in the inner lead portion of the lead frame extending from the clamped portion into the cavity toward the other of the pair of molds, and a resin sealing process in which resin is injected into the cavity to form the sealing resin portion. [Effects of the Invention]

[0011] According to the present invention, when the lead frame is clamped, stress is generated in the lead frame in a direction that causes the inner lead portion to move toward the mold, making it difficult for a gap to form between the inner lead portion and the mold through which the encapsulating resin can get in, thereby suppressing the occurrence of resin burrs in the manufacturing of a semiconductor device. Also, it becomes possible to manufacture a semiconductor device in which the inner lead portion is difficult to peel off from the encapsulating resin portion. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an explanatory view of one embodiment (embodiment 1) of the method for manufacturing a semiconductor device of the present invention, and is a cross-sectional schematic view of a state in which a lead frame is clamped. [Figure 2] 2 is a cross-sectional view illustrating deformation of the clamped lead frame shown in FIG. 1. FIG. [Figure 3] 2 is a diagram showing the results of a simulation of stress generated in an inner lead portion of the lead frame shown in FIG. 1. FIG. [Figure 4] 3 is a cross-sectional view showing a semiconductor device in which the lead frame shown in FIG. 2 is sealed with resin. [Figure 5] 2 is a diagram showing the results of a simulation of elastic energy generated at the tip of an inner lead portion of the lead frame shown in FIG. 1. FIG. [Figure 6] 1 is a cross-sectional view showing a state in which a lead frame is clamped in a mold having multiple cavities in embodiment 1. FIG. [Figure 7] FIG. 2 is an explanatory view of another embodiment (embodiment 2) of the method for manufacturing a semiconductor device of the present invention, and is a cross-sectional schematic view of a state in which a lead frame is clamped. [Figure 8] FIG. 1 is a diagram for explaining a general method for manufacturing a semiconductor device, and is a schematic cross-sectional view showing a state in which a lead frame is clamped. [Figure 9] 9 is a cross-sectional view illustrating deformation of the clamped lead frame shown in FIG. 8. FIG. [Figure 10] 10 is a cross-sectional view showing a semiconductor device in which the lead frame shown in FIG. 9 is sealed with resin. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the method for manufacturing a semiconductor device according to the present invention, when a lead frame carrying a semiconductor element is clamped between a pair of molds, a pressing force is applied to the lead frame to generate stress in the direction of the inner lead portion toward the mold, and resin is injected into the cavity to form an encapsulating resin portion. As a result, the occurrence of resin burrs on the surface of the inner lead portion exposed from the encapsulating resin portion is suppressed, and a semiconductor device is manufactured in which the lead frame is less likely to peel from the encapsulating resin portion. In this invention, the term "inner lead portion" refers to at least either an inner lead portion having one free end or an inner lead portion connected to a die pad portion having one free end.

[0014] Next, embodiments of the method for manufacturing a semiconductor device of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments, and the members, materials, etc. described below can be variously modified within the scope of the spirit of the present invention. Furthermore, in the drawings, the same reference numerals indicate equivalent or identical items, and the size and positional relationship between each component is for convenience's sake.

[0015] (Embodiment 1) 1 is an explanatory diagram of one embodiment (embodiment 1) of the method for manufacturing a semiconductor device of the present invention, and is a schematic cross-sectional view of a lead frame in a clamped state. In the method for manufacturing a semiconductor device of this embodiment, as shown in FIG. 1, a semiconductor element 1 is mounted on a die pad portion 2a, and a lead frame 2 having electrodes of the semiconductor element 1 and inner lead portions 2b connected by metal wires 3 is clamped between a pair of molds 4A and 4B and clamped. The clamped lead frame has inner lead portions 2b extending from a clamped portion 2c into a cavity 5.

[0016] In the method for manufacturing a semiconductor device of this embodiment, the lead frame 2 is clamped using a pair of molds consisting of a first mold 4A having a cavity 5 and a recess 9, and a flat second mold 4B. The first mold 4A differs from the mold 4a described in FIGS. 8 and 9 in that it has the recess 9, while the second mold 4B has the same structure as the mold 4b described in FIGS. 8 and 9. The recess 9 has a wall 9a that slopes away from the cavity 5. The space between this wall 9a and a sidewall 5a of the cavity 5 that slopes in the opposite direction to the slope of the wall 9a forms the clamping portion 6A of the first mold 4A.

[0017] 2 is a cross-sectional view illustrating deformation of the clamped lead frame shown in FIG. 1. When the lead frame 2, which is disposed so as to abut against the second mold 4B, is clamped between a first mold 4A having a cavity 5 and a recess 9 and a flat second mold 4B, a pressing force is applied from the clamping portion 6A of the first mold 4A to the clamped portion 2c of the lead frame 2. This pressing force includes a pressing force applied to the clamped portion 2c in a direction perpendicular to the upper surface of the clamped portion 2c indicated by arrow A, a pressing force applied to the clamped portion 2c in a direction following the shape of the side wall portion 5a of the cavity 5 indicated by arrow B (hereinafter also referred to as the "first pressing force"), and a pressing force applied to the clamped portion 2c in a direction inclined away from the cavity 5 indicated by arrow C (hereinafter also referred to as the "second pressing force").

[0018] In the example shown in FIGS. 1 and 2, the second pressing force is applied in a direction that follows the shape of the wall 9a of the recess 9, which is inclined in the opposite direction to the inclination of the side wall 5a of the cavity 5.

[0019] When a pressing force including pressing forces applied in the directions indicated by the arrows A to C is applied from the mold clamping portion 6A of the first mold 4A to the clamped portion 2c of the lead frame 2, stress is generated in the lead frame 2.

[0020] FIG. 3 shows the results of a simulation of stresses generated in the inner leads of the lead frame shown in FIG. 1. As an example, FIG. 3 shows, as "Embodiment 1," the results of a simulation of normal stresses in a direction perpendicular to the upper surface of second mold 4B when lead frame 2, made of a predetermined material and having a predetermined thickness, is clamped under a predetermined pressure using first mold 4A and second mold 4B with the cross-sectional shapes shown in FIGS. 1 and 2. Sidewall 5a of cavity 5 in first mold 4A is shaped with a slope that intersects with the upper surface of second mold 4B at an angle of 80 degrees, and wall 9a of recess 9 is shaped with a slope that intersects with the upper surface of second mold 4B at an angle of 45 degrees, resulting in a shape in which the second pressing force is greater than the first pressing force. For comparison, as "Conventional Example," the results of a simulation of a lead frame having the same shape as lead frame 2 described above when clamped under the same conditions using molds 4a (without recess 9) and 4b shown in FIG. 8 are shown.

[0021] The simulation results show the normal stress values ​​at the tip of the inner lead portion 2b, at a position 50 μm from the tip of the inner lead portion 2b, and at a position 150 μm from the tip of the inner lead portion 2b. The "tip" refers to the open end of the inner lead portion 2b. Stress in the direction toward the underside of the inner lead portion 2b (toward the second mold 4B) is shown as a positive relative value, and stress in the opposite direction is shown as a negative relative value. A positive normal stress value indicates that the inner lead portion 2b is under stress that deforms it in a direction toward the second mold 4B, and a negative normal stress value indicates that the inner lead portion 2b is under stress that deforms it in a direction away from the second mold 4B.

[0022] As shown in Fig. 3, it was confirmed that the direction of the vertical stress when clamping is performed by the semiconductor device manufacturing method of this embodiment ("Embodiment 1" in Fig. 3) is opposite to the direction of the vertical stress when compared with the conventional example ("Conventional Example" in Fig. 3). Specifically, in the conventional example, clamping generates a vertical stress that deforms the inner lead portion 2b shown in Fig. 8 in a direction away from the mold 4b, whereas in Embodiment 1, it is found that a vertical stress that deforms the inner lead portion 2b shown in Fig. 1 in a direction approaching (facing) the second mold 4B is generated.

[0023] 1, the inner lead portion 2b is configured to extend parallel to the upper surface of the second mold 4B from the clamped portion 2c into the cavity 5, so if there is a gap between the inner lead portion 2b and the second mold 4B when the lead frame 2 is clamped, the inner lead portion 2b will be deformed in a direction pressing it against the second mold 4B. If there is no gap between the inner lead portion 2b and the second mold 4B, the inner lead portion 2b will not deform, and stress will be generated in a direction pressing it against the second mold 4B.

[0024] Fig. 4 is a cross-sectional view of a semiconductor device in which the lead frame shown in Fig. 2 is resin-encapsulated. When the lead frame 2 is clamped as shown in Fig. 2, the inner lead portion 2b is easily brought into contact with the second mold 4B without any gaps. When resin is injected into the cavity 5 in this state, an encapsulating resin portion 7 is formed as shown in Fig. 4, which suppresses the occurrence of resin burrs on the underside of the inner lead portion 2b, and in some cases, no resin burrs are generated at all.

[0025] FIG. 5 shows the results of a simulation of elastic energy generated at the tip of the inner lead portion of the lead frame shown in FIG. 1. As an example, FIG. 5 shows, as "Embodiment 1," the results of a simulation of elastic energy generated at the tip of the inner lead portion 2b when a lead frame 2 made of a predetermined material and having a predetermined thickness is clamped using the first mold 4A and second mold 4B having the cross-sectional shapes shown in FIGS. 1 and 2 under various clamping load conditions. The sidewall 5a of the cavity 5 of the first mold 4A is shaped with a slope that intersects with the upper surface of the second mold 4B at an angle of 80 degrees, and the wall 9a of the recess 9 is shaped with a slope that intersects with the upper surface of the second mold 4B at an angle of 45 degrees, so that the second pressing force is greater than the first pressing force. For comparison, the results of a simulation of a lead frame having the same shape as the lead frame 2 described above when clamped using the molds 4a (without the recess 9) and 4b shown in FIG. 8 under various clamping load conditions are shown as relative values ​​and are referred to as a "Conventional Example." The elastic energy at the tip of the inner lead portion 2b is the energy stored inside due to deformation, and if this value is large, the force that tries to return to the original shape when released from the mold clamping will be large.

[0026] As shown in FIG. 5, the elastic energy when clamped by the semiconductor device manufacturing method of this embodiment ("Embodiment 1" in FIG. 5) is smaller than the elastic energy of the conventional example ("Conventional Example" in FIG. 5).

[0027] Furthermore, from the simulation results of the vertical stress generated in the inner lead portion 2b of the lead frame 2 shown in Figure 3 above, when there is a gap between the inner lead portion 2b and the second mold 4B and deformation occurs in the direction of pressing the inner lead portion 2b against the second mold 4B, resin is injected into the cavity 5 to form the semiconductor device shown in Figure 4, and when the lead frame 2 is released from the mold clamping, stress is generated that causes the inner lead portion 2b to deform in a direction approaching the sealing resin portion 7.

[0028] Therefore, since the elastic energy, which is the force that tries to return to the original shape, is small and the direction of deformation is opposite to the direction of peeling, the inner lead portion 2b exposed from the sealing resin portion 7 will not peel off from the sealing resin portion 7.

[0029] Even if there is no gap between the inner lead portion 2b and the second mold 4B, the elastic energy, which is the force that tries to return to its original shape, is small, so the inner lead portion 2b exposed from the sealing resin portion 7 will not peel off from the sealing resin portion 7.

[0030] Next, the setting of the magnitude of the second pressing force will be described. Generally, the shape of the cavity 5 is determined according to the shape of the sealing resin portion 7 formed by injecting resin. Furthermore, in consideration of the releasability of the sealing resin portion 7 from the mold, the side wall portion 5a is formed to have an inclined shape as shown in FIG. 1. In this way, the first pressing force applied in a direction along the shape of the side wall portion 5a of the cavity 5 inclined at an inclination angle θ1 (the angle formed between the side wall portion 5a of the cavity 5 and the upper surface of the second mold 4B) can be offset by the second pressing force applied in a direction along an inclined surface symmetrical to the side wall portion 5a inclined at θ1 (i.e., a surface inclined at an inclination angle θ2 on the opposite side from the cavity 5).

[0031] Furthermore, the magnitude of the second pressing force can also be adjusted by the size of the mold clamping portion 6A of the first mold 4A, that is, the position where the wall portion (wall portion 9a of the recess 9) shaped to slope in the opposite direction to the cavity 5 is disposed.

[0032] For example, to make the second pressing force greater than the first pressing force, a wall 9a is formed that is inclined toward the opposite side of the cavity 5 at an angle θ2 (θ2<θ1) (the angle formed by the wall 9a on the cavity 5 side of the recess 9 and the upper surface of the second mold 4B), and a pressing force is applied in a direction that follows the shape of this wall 9a.

[0033] Furthermore, if the second pressing force and the first pressing force cancel each other out so that the inner lead portion 2b is not deformed in a direction away from the second mold 4B and no gap is created between the inner lead portion 2b and the second mold 4B, the second pressing force and the first pressing force are set equal. In this case, if the relationship between the inclination angle θ1 and the first pressing force and the relationship between the inclination angle θ2 and the second pressing force are expressed by the same function, the inclination angle θ1 of the side wall portion 5a of the cavity 5 and the inclination angle θ2 of the wall portion 9a inclined in the direction opposite to the cavity 5 may be set equal to each other so that the second pressing force and the first pressing force are equal.

[0034] As an example of a wall portion sloping away from the cavity 5, a recess 9 having an isosceles triangular cross section is provided in the first mold 4A in FIGS. 1 and 2. When such a recess 9 is provided, two walls 9a corresponding to the two hypotenuses of the isosceles triangle can form a mold clamping portion 6 between the side walls 5a of the opposing cavities 5. As a more specific example, FIG. 6 shows a cross-sectional schematic diagram of a lead frame clamped by a mold having multiple cavities in the first embodiment. As shown in FIG. 6, multiple cavities 51 and 52 are arranged adjacent to each other in the first mold 4A, and a recess 9 is arranged between them. The mold clamping portion 6 is formed between the side wall 51a of the cavity 51 and the wall 91a of the recess 9, and another mold clamping portion 6 is formed between the side wall 52a of the cavity 52 and the wall 92a of the recess 9. By arranging the recess 9 having an isosceles triangular cross section between the cavities 51 and 52 in this manner, the area occupied by the recess 9 in the first mold 4A can be reduced.

[0035] As described above, when the lead frame 2 is clamped, stress is generated in the lead frame 2 in a direction that causes the inner lead portion 2b to move toward the second mold 4B, and when the lead frame 2 is released from the clamping state, stress is generated that causes the inner lead portion 2b to deform in a direction that approaches the sealing resin portion 7. Therefore, the lead frame used in the manufacturing method of the semiconductor device of this embodiment can be selected from materials that elastically deform when clamped. For example, a commonly used copper lead frame made of copper or a copper alloy can be selected.

[0036] (Embodiment 2) 7 is an explanatory diagram of another embodiment (Embodiment 2) of the method for manufacturing a semiconductor device of the present invention, and is a schematic cross-sectional view of the lead frame in a clamped state. Compared to the method for manufacturing a semiconductor device described in Embodiment 1 above, this embodiment differs in that the clamped lead frame 2 has inner lead portions 2d that extend from the clamped portion 2c into the cavity 5 and are connected to the die pad portion 2a. The first mold 4A and second mold 4B have the same shapes as those in Embodiment 1. Note that the clamping of the inner lead portions 2b and the inner lead portions 2d connected to the die pad portion 2a is the same as the clamping of the inner lead portions 2b described in Embodiment 1 above, so a detailed description will be omitted.

[0037] In the method for manufacturing a semiconductor device of this embodiment, when the lead frame 2 is clamped between a pair of molds, which are made up of a first mold 4A having a cavity 5 and a recess 9 and a flat second mold 4B, a pressing force including pressing forces applied in the directions indicated by arrows A to C described in Fig. 2 is applied from the mold clamping portion 6A of the first mold 4A to the clamped portion 2c of the lead frame 2. As a result, a stress is generated in the lead frame 2 in a direction in which the inner lead portion 2d connected to the die pad portion 2a approaches (moves toward) the second mold 4B.

[0038] 7, the inner lead portions 2d connected to the die pad portion 2a extend from the clamped portion 2c into the cavity 5 in parallel with the upper surface of the second mold 4B. When the lead frame 2 is clamped, if there is a gap between the inner lead portions 2d connected to the die pad portion 2a and the second mold 4B, deformation occurs in a direction pressing the inner lead portions 2d connected to the die pad portion 2a against the second mold 4B. If there is no gap between the inner lead portions 2d connected to the die pad portion 2a and the second mold 4B, the inner lead portions 2d connected to the die pad portion 2a do not deform, and stress occurs in a direction pressing the inner lead portions 2d connected to the die pad portion 2a against the second mold 4B.

[0039] 7, when the lead frame 2 is clamped, the inner lead portions 2d connected to the die pad portion 2a are easily brought into contact with the second mold 4B without any gaps. When resin is injected into the cavity 5 in this state to form the sealing resin portion, the occurrence of resin burrs on the lower surfaces of the inner lead portions 2d connected to the die pad portion 2a is suppressed or prevented.

[0040] There is a gap between the inner lead portion 2d connected to the die pad portion 2a and the second mold 4B, and when the sealing resin portion is formed in a state in which deformation occurs in the direction of pressing the inner lead portion 2d connected to the die pad portion 2a against the second mold 4B and the lead frame 2 is released from the mold clamping, stress is generated that causes the inner lead portion 2d connected to the die pad portion 2a to deform in a direction approaching the sealing resin portion.

[0041] As explained above, the elastic energy, which is the force that tries to return to the original shape, is small, and the direction of deformation is opposite to the direction of peeling, so the inner lead portion 2d connected to the die pad portion 2a exposed from the sealing resin portion will not peel off from the sealing resin portion.

[0042] Even if there is no gap between the inner lead portion 2d connected to the die pad portion 2a and the second mold 4B, the elastic energy, which is the force with which the inner lead portion 2d connected to the die pad portion 2a tries to return to its original shape, is small, so the inner lead portion 2d connected to the die pad portion 2a will not peel off from the sealing resin portion.

[0043] The above describes an embodiment of the method for manufacturing a semiconductor device of the present invention, but the present invention is not limited to the above embodiment, and the shape of cavity 5 can be set appropriately as long as the releasability of the sealing resin from the mold can be ensured.

[0044] The die pad portion 2 a may be configured not to be exposed from the sealing resin portion. In this case, in the example described in the second embodiment, the die pad portion 2 a may be configured to be offset from the inner lead portion 2 d rather than being formed on the same plane.

[0045] The second mold 4B is not limited to a flat plate shape, and can be modified in various ways as long as it is capable of applying a pressing force including the first and second pressing forces to the lead frame 2 and generates stress in the direction toward the second mold 4B on the inner lead portions 2b, 2d of the lead frame 2.

[0046] The wall portion 9a inclined on the opposite side of the cavity 5, which constitutes the mold clamping portion 6 together with the side wall portion 5a of the cavity 5, is not limited to a configuration formed by the recess 9, and can be variously modified, for example, to be the outer wall of the mold, the inner wall of a through hole penetrating the mold, etc.

[0047] (summary) (1) One embodiment of the method for manufacturing a semiconductor device of the present invention is a method for manufacturing a semiconductor device in which a lead frame having a semiconductor element mounted thereon is clamped between a pair of molds and clamped, and resin is injected into the cavity to form a sealing resin portion, the method including: a mold clamping step in which a clamped portion of one of the pair of molds applies a pressing force to a clamped portion of the lead frame, the pressing force including a first pressing force applied in a direction along the shape of the side wall portion of the cavity and a second pressing force applied in a direction inclined toward the opposite side of the cavity, thereby causing stress in the inner lead portion of the lead frame extending from the clamped portion into the cavity toward the other of the pair of molds; and a resin sealing step in which resin is injected into the cavity to form the sealing resin portion.

[0048] According to the manufacturing method of a semiconductor device of (1) above, when the lead frame is clamped, stress is generated in the lead frame in a direction that moves the inner lead portion toward the mold, which prevents the encapsulating resin from getting between the inner lead portion and the mold, making it possible to manufacture a semiconductor device with no or little resin burrs. Also, when the mold is released, stress is likely to be generated in a direction that moves the inner lead portion toward the encapsulating resin portion, making it possible to manufacture a semiconductor device in which the lead frame does not or is difficult to peel from the encapsulating resin portion.

[0049] (2) According to another embodiment, in the method for manufacturing a semiconductor device of (1) above, the mold clamping step is a step of applying the second pressing force, which is greater than the first pressing force, from the mold clamping portion to the clamped portion.

[0050] (3) According to another embodiment, in the method for manufacturing a semiconductor device of (1) above, the pair of molds is composed of one mold having the cavity and a wall portion inclined in the opposite direction to the inclination of the side wall portion of the cavity, and the other mold having a flat shape, and the mold clamping process is a process of applying the pressing force, including the second pressing force applied along a direction following the shape of the wall portion, to the mold clamped portion from the mold clamping portion formed between the side wall portion and the wall portion.

[0051] (4) According to yet another embodiment, in the method for manufacturing a semiconductor device according to (3) above, the one mold comprises the cavity and the recess, and the recess comprises the wall portion. [Explanation of symbols]

[0052] 1. Semiconductor element 2 Lead Frame 2a Die pad section 2b, 2d inner lead part 2c Clamped part 3 Metal Wire 4a, 4b mold 4A No. 1 mold 4B 2nd mold 5, 51, 52 cavities 5a, 51a, 52a side wall part 6, 6A mold clamping section 7 Sealing resin part 8 Resin burrs 9 Recess 9a, 91a, 92a Wall section

Claims

1. A method for manufacturing a semiconductor device, comprising clamping a lead frame on which a semiconductor element is mounted between a pair of molds and clamping the molds, and injecting resin into a cavity to form a sealing resin portion, a mold clamping process in which a pressing force including a first pressing force applied from a mold clamping portion of one of the pair of molds to a clamped portion of the lead frame in a direction along the shape of a side wall portion of the cavity and a second pressing force applied in a direction inclined toward the opposite side of the cavity is applied, thereby generating stress in a direction toward the other of the pair of molds in an inner lead portion of the lead frame extending from the clamped portion into the cavity; a resin sealing step of injecting a resin into the cavity to form the sealing resin portion.

2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the mold clamping step is a step of applying the second pressing force, which is greater than the first pressing force, from the mold clamping portion to the clamped portion.

3. the pair of molds includes one mold having the cavity and a wall portion inclined in a direction opposite to the inclination of the side wall portion of the cavity, and the other mold having a flat plate shape; 2. The method for manufacturing a semiconductor device according to claim 1, wherein the mold clamping process is a process of applying a pressing force, including the second pressing force, to the clamped portion from the mold clamping portion formed between the side wall portion and the wall portion in a direction along the shape of the wall portion.

4. the one mold includes the cavity and the recess, The method for manufacturing a semiconductor device according to claim 3 , wherein the recessed portion includes the wall portion.

Images