JP2013102044A - Semiconductor device manufacturing method, and lead cutting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain dispersion of cutting chips and residue of the cutting chips with a simple constitution.SOLUTION: A semiconductor device manufacturing method includes steps of: cutting a tip part 202 by shearing with a die 20 and a punch 50 while the tip part 202 of an external lead (lead 201) of a semiconductor device 200 is held by the die 20 and a presser member 40; and isolating the die 20 from the presser member 40. An elastic body (for example, plate-like elastic body 80) projecting from face of the presser member 40 on the die 20 side toward the die 20 is provided on the presser member 40. When the external lead is held by the die 20 and the presser member 40, the elastic body is pressed by the die 20 and is elastically deformed to a side opposite to the die 20. The die 20 is isolated from the presser member 40, and therefore, the elastic body is elastically returned toward the die 20. The tip part 202 that become a cutting chip 203 by cutting is removed from the presser member 40 and the die 20 by the elastic body.

Description

  The present invention relates to a semiconductor device manufacturing method and a lead cutting device.

  Some semiconductor devices include a sealing resin having a semiconductor chip sealed therein and a plurality of leads protruding from the side surface of the sealing resin. In general, a lead of such a semiconductor device is processed into a predetermined shape by bending and cutting (cutting) a tip portion thereof after being bent into a gull wing shape or the like.

  Cutting of the leading end of the lead is performed by pressing using a mold. The mold includes a mounting portion on which the semiconductor device is mounted, a punch that descends toward the lead on the mounting portion, and a die that cuts the tip of the lead in cooperation with the punch. (See Patent Document 1).

  By cutting and removing the tip portion of the lead, the tip portion becomes cutting waste. The cutting waste is discharged outside the mold through a discharge path provided in the mold for press working. This discharge path is generally a drop hole formed in the lower mold among the upper and lower molds.

  It has been known that when cutting the leads, cutting chips are scattered to cause adverse effects such as a decrease in yield (see Patent Document 1).

In Patent Document 1, when cutting waste is scattered to the side, a scattering prevention body that reflects the cutting waste and drops downward, and a splash prevention body that prevents the cutting waste from scattering upward, are described as a mold. Is provided.
Patent Document 1 further describes that an external force addition body that applies an external force in the dropping direction to the cutting waste is provided in the punch holder so that the cutting waste does not fly over the scattering prevention body.

  In Patent Documents 2 and 3, a technique for preventing the scattering of cutting waste by performing cutting in a state in which the tip portion of the lead (the portion that becomes cutting waste by cutting) is sandwiched between a die and a stripper of a mold. Is described.

In Patent Document 4, the cutting waste remaining on the die (lead cut punch of the same document) is discharged by an airflow flowing through a vent hole formed in the punch (lead cut die of the same document). Is described.
Patent Document 5 describes that cutting waste remaining on a punch is pushed and discharged by moving a die laterally.
Patent Document 6 describes that cutting waste adhering to the lower surface of a die of a mold is separated from the die by scraping off by moving another part of the mold horizontally.

JP 2000-40782 A JP-A-8-172153 JP 2009-94102 A JP 2008-166515 A JP 2005-12130 A JP 2003-170229 A

  In the techniques of Patent Documents 2 and 3, since the cutting process is performed with the leading end of the lead sandwiched, it may be possible to prevent the scattering of the cutting waste, but the cutting waste may remain on the die or the lower surface of the stripper. As a result, the processing accuracy of the lead may be deteriorated.

  In the technique of Patent Document 1, unlike the techniques of Patent Documents 2 and 3, since the tip portion of the lead (the portion that becomes cutting waste by cutting) is not sandwiched, the cutting waste is scattered. For this reason, in the technique of Patent Document 1, it is necessary to provide a scattering prevention body, a splash prevention body, an external force addition body, and the like in the mold in order to discharge the scattered cutting waste by reflecting it through the discharge path. There is.

  In the technique of Patent Document 4, it is necessary to form a vent hole in the punch.

  In the techniques of Patent Documents 5 and 6, it is necessary to use a mold having a special moving mechanism for moving parts in the horizontal direction.

  Thus, it was difficult to suppress the scattering of cutting waste and the remaining cutting waste with a simple configuration.

The present invention includes a step of cutting the tip by shearing with the die and the punch in a state where the tip of the external lead of the semiconductor device is sandwiched between the die and the pressing member;
Separating the die and the pressing member;
Have
The pressing member is provided with an elastic body that protrudes toward the die side from the die side surface of the pressing member,
When sandwiching the tip portion between the die and the pressing member, the elastic body is pushed by the die and elastically deformed to the opposite side of the die,
By separating the die and the pressing member, the elastic body is elastically returned to the die side, and the tip portion that has become cutting waste by the cutting can be removed from the pressing member and the die by the elastic body. A method for manufacturing a semiconductor device is provided.

According to this manufacturing method, first, the outer lead is sandwiched between the die and the holding member, and the elastic body is elastically deformed to the opposite side of the die. Disconnect. Thereafter, by separating the die and the pressing member, the elastic body can be elastically returned to the die side, and the tip portion that has become cutting waste by cutting can be removed from the pressing member and the die by the elastic body.
That is, since the tip portion of the external lead is cut in a state where the external lead is sandwiched between the die and the pressing member, scattering of cutting waste can be suppressed. Moreover, with a simple configuration in which the pressing member is provided with an elastic body, the cutting waste can be discharged from the pressing member and the die.
Therefore, scattering of cutting waste and residual cutting waste can be suppressed with a simple configuration.

Further, the present invention provides a mounting unit on which a semiconductor device having an external lead is mounted so that a tip portion of the external lead protrudes;
A die disposed adjacent to the mounting portion;
A pressing member sandwiched between the die by pressing the tip of the external lead against the die; and
A punch for cutting the tip by shearing in cooperation with the die;
An elastic body provided on the pressing member and projecting toward the die side from a surface of the pressing member on the die side;
Have
By sandwiching the external lead between the die and the pressing member, the elastic body is pressed by the die and elastically deformed to the opposite side of the die,
There is provided a lead cutting device characterized in that the elastic body is elastically returned to the die side by separating the die and the pressing member.

  According to the present invention, scattering of cutting waste and residual cutting waste can be suppressed with a simple configuration.

It is a typical side view showing the lead cutting device concerning an embodiment. It is a typical bottom view showing the holding member of the lead cutting device concerning an embodiment, and its peripheral structure. It is a typical side view showing the holding member of the lead cutting device concerning an embodiment, and the structure of the circumference. It is a typical side view showing a flow of a series of operations of a lead cutting device concerning an embodiment. It is a typical side view showing a flow of a series of operations of a lead cutting device concerning an embodiment. It is a typical top view which shows the flow of a manufacturing process of the external lead of a semiconductor device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  FIG. 1 is a schematic side view showing a lead cutting apparatus 100 according to an embodiment. FIG. 2 is a schematic bottom view showing the pressing member 40 of the lead cutting device 100 and the structure around it. FIG. 3 is a schematic side view showing the pressing member 40 of the lead cutting device 100 and the surrounding structure. 4 and 5 are schematic side views showing a flow of a series of operations of the lead cutting apparatus 100. FIG. FIG. 6 is a schematic plan view showing a flow of processing steps for the lead 201 of the semiconductor device 200.

A lead cutting apparatus 100 for a semiconductor device according to the present embodiment includes a mounting portion (for example, knockout 10) on which a semiconductor device 200 having an external lead (lead 201) is mounted such that a tip portion 202 of the external lead protrudes. In cooperation with the die 20, the pressing member 40 sandwiched between the die 20 disposed adjacent to the mounting portion, the tip portion 202 of the external lead 202 against the die 20, and the die 20. The punch 50 which cuts the front-end | tip part 202 by shear, and the elastic body (for example, plate-shaped elastic body 80) provided in the pressing member 40 and protruded in the die | dye 20 side from the surface at the side of the die 20 in the pressing member 40 are included. By holding the external lead between the die 20 and the pressing member 40, the elastic body is pressed by the die 20 and elastically deformed to the opposite side of the die 20. By separating the die 20 and the pressing member 40, the elastic body is elastically returned to the die 20 side.
Details will be described below.

  The semiconductor device 200 to be processed electrically connects, for example, a lead frame (not shown) having a plurality of leads and a die pad, a semiconductor chip (not shown) mounted on the die pad, and the semiconductor chip and the leads. It has a bonding wire (not shown) to be connected, and a semiconductor chip, a die pad, a bonding wire, and a sealing resin 205 that seals the base end portion of the lead inside.

  A portion of the lead that protrudes outside the sealing resin is referred to as an external lead (outer lead). Hereinafter, the external lead is simply referred to as lead 201. The tip portion 202 of the lead 201 is cut by the lead cutting device 100 to become cutting waste 203 (FIGS. 5A to 5C).

  The lead cutting device 100 includes a lower mold (described later), an upper mold (described later) that moves up and down relative to the lower mold, and a press device (not shown) that moves the upper mold up and down relative to the lower mold. The tip 202 of the lead 201 is cut by the cooperation of the lower mold and the upper mold.

  As shown in FIG. 1, the lower die of the lead cutting device 100 includes a knockout 10 on which a semiconductor device 200 to be processed is placed, a die 20, a die plate 30, a die holder (lower die holder) (not shown), have.

  The die plate 30 is placed on the die holder. An opening 31 penetrating the die plate 30 vertically is formed at the center of the die plate 30.

  The knockout 10 is disposed in the inner region of the opening 31 of the die plate 30 and is supported by the upper surface of the die holder via a compression coil spring (not shown). The knockout 10 can be lowered relative to the die plate 30 and the die holder against the bias of the compression coil spring.

A semiconductor device 200 to be processed is placed on the upper surface of the knockout 10. Knockout 10 has a rectangular shape in plan view.
Here, for example, as illustrated in FIG. 6, the sealing resin 205 of the semiconductor device 200 is formed in a rectangular shape in plan view, and a plurality of leads 201 protrude from each of the four sides in the plan view.
The semiconductor device 200 is mounted on the knockout 10 so that each side of the sealing resin 205 and each side in the plan view of the knockout 10 are parallel, and the tip portion 202 of each lead 201 protrudes from the knockout 10. Placed.

The die 20 is disposed adjacent to the periphery of the knockout 10.
The lead cutting device 100 has, for example, four dies 20, and each die 20 is arranged corresponding to each side of the sealing resin 205. Each die 20 collectively cuts the front end portions 202 of the plurality of leads 201 protruding from the corresponding sides of the sealing resin 205. In FIG. 1, only one of the plurality of dies 20 is illustrated.

  The die 20 is placed on a die holder. For this reason, the relative positional relationship between the die holder, the die 20 and the die plate 30 is substantially always constant. Therefore, when the knockout 10 is lowered relative to the die plate 30 and the die holder, the knockout 10 is also lowered relative to the die 20.

  In the upper part of the die 20, the part facing the inner peripheral wall of the opening 31 of the die plate 30 is an inclined surface 21 that is inclined downward toward the outside (direction away from the knockout 10). The upper end surface 22 of the die 20 is a horizontal plane.

  A region between the die 20 and the die plate 30 constitutes a discharge hole 32 for discharging the cutting waste 203. The lead cutting device 100 is configured to discharge the cutting waste 203 to the outside through the discharge hole 32.

  As shown in FIG. 1, the upper die of the lead cutting device 100 includes an upper die holder 70, a punch plate 60, a punch 50, a pressing member 40, and a pressing pin 55.

  The upper mold holder 70 is held by a pressing device (not shown), and is moved up and down relative to the lower mold by the pressing device.

  A punch 50 and a punch plate 60 are fixed to the lower surface of the upper mold holder 70. Further, a bottom dead center stopper 61 is fixed to the lower surface of the punch plate 60. For this reason, the relative positional relationship among the upper die holder 70, the punch 50, the punch plate 60, and the bottom dead center stopper 61 is substantially always constant.

  When the upper die is lowered to the bottom dead center, the lower end portion of the bottom dead center stopper 61 comes into contact with the upper surface of the die plate 30, and the lowering of the upper die is stopped.

  An opening 62 penetrating the punch plate 60 in the vertical direction is formed at the center of the punch plate 60. A punch 50 is disposed in the opening 62.

  The punch 50 is located above the knockout 10, and the punch 50 and the knockout 10 face each other vertically.

  The punch 50 includes a main body portion 51 and a contact portion 52 that protrudes downward from the peripheral edge portion of the main body portion 51. As the upper mold is lowered, the contact portion 52 contacts the upper surface of the lead 201. When the upper die is further lowered, the abutting portion 52 pushes the knockout 10 downward through the lead 201 (presses downward against the bias of the spring) and cooperates with the die 20 to move the tip portion 202. Is cut by shearing.

  On the lower surface of the punch 50, the sealing resin 205 and the proximal end portion of the lead 201 (with respect to the portion of the lead 201 where the contacting portion 52 contacts) with the contacting portion 52 in contact with the upper surface of the lead 201. An accommodating recess 53 is formed for accommodating the end portion.

The pressing pin 55 presses the sealing resin 205 of the semiconductor device 200 from above and restricts the floating of the semiconductor device 200, and is provided on the punch 50.
The punch 50 is formed with an insertion hole 58 that vertically penetrates the punch 50. The pressing pin 55 is formed in a vertically long shape, and is inserted through the insertion hole 58 so that a lower end portion thereof protrudes into the housing recess 53 of the punch 50. A retaining portion 56 is fixed to the upper end of the pressing pin 55. The retaining portion 56 is formed in a size and shape that cannot enter the insertion hole 58. Therefore, the pressing pin 55 is prevented from falling off the punch 50.
The lower end of the compression coil spring 57 is fixed to the upper surface of the retaining portion 56. The upper end of the compression coil spring 57 is fixed to the upper mold holder 70 or the press device. The compression coil spring 57 urges the retaining portion 56 and the pressing pin 55 downward by its elastic force.

When the upper die is lowered, the pressing pin 55 comes into contact with the upper surface of the sealing resin 205 before the contact portion 52 of the punch 50 comes into contact with the upper surface of the lead 201, and the compression coil spring 57 biases the pressing pin 55. Then, the sealing resin 205 is pressed downward.
Even after the pressing pin 55 comes into contact with the upper surface of the sealing resin 205, the upper die is lowered. At that time, the pressing pin 55 and the retaining portion 56 rise relative to the punch 50 against the urging force of the compression coil spring 57.

  The pressing member 40 includes, for example, a main body portion 41 and a clamping portion 42.

  For example, the main body 41 extends from the upper position of the die plate 30 to the upper position of the discharge hole 32. For example, the lower surface and the upper surface of the main body 41 are flat and horizontal. The main body 41 is formed in a rectangular parallelepiped shape, for example.

The sandwiching portion 42 is formed integrally with the main body portion 41 so as to protrude sideward (punch 50 side) from the side surface of the main body portion 41 facing the punch 50 side. The clamping part 42 extends from the position above the discharge hole 32 to the position above the die 20. The lower part of the clamping part 42 protrudes below the lower surface of the main body part 41. The clamping part 42 is arranged so as not to be buffered with the die plate 30 even when the upper mold is lowered to the bottom dead center.
Note that the upper surface of the clamping part 42 and the upper surface of the main body part 41 are flush with each other.

  The pressing member 40 is provided corresponding to each die 20, for example. That is, the lead cutting device 100 has, for example, four pressing members 40 around the punch 50.

As shown in FIG. 2, the pressing member 40 has a plurality of clamping portions 42. The plurality of sandwiching portions 42 are arranged in a line at a predetermined interval (for example, a constant interval).
In FIG. 2, the arrangement of the leads 201 is indicated by a dotted line. The arrangement direction of the plurality of sandwiching portions 42 is the same as the arrangement direction of the plurality of leads 201 protruding from one side of the sealing resin 205 of the semiconductor device 200 placed on the knockout 10.

Each clamping part 42 has, for example, a strip shape in the planar shape (the shape of the lower surface). The lower surface of each clamping part 42 is respectively flat and horizontal, and is flush with each other.
These sandwiching portions 42 face the die 20 in the vertical direction, and sandwich the tip portion 202 of the lead 201 between the die 20.

  The plate-like elastic body 80 is a leaf spring, and has, for example, a first portion 81 and a second portion 82 each formed in a flat plate shape.

  For example, the first portion 81 is fixed to the lower surface of the main body portion 41 by a fastening member such as a bolt 84 such that one plate surface thereof is in contact with the lower surface of the main body portion 41. For example, the first portion 81 is disposed from the upper position of the die plate 30 to the upper position of the discharge hole 32.

  The second part 82 is formed integrally with the first part 81. The second portion 82 is located on the punch 50 side (knockout 10 side) with respect to the first portion 81. The second portion 82 extends from the position above the discharge hole 32 to the position above the die 20. The second portion 82 is bent (refracted as an example) with respect to the first portion 81. The direction of this bending is obliquely downward, and the second portion 82 is located lower as it is farther from the first portion 81.

  The tip (lower end) of the second portion 82 is located outward (on the discharge hole 32 side) from the upper end surface 22 of the die 20 with respect to the knockout 10. The tip of the second portion 82 is located above the inclined surface 21, for example.

  The lower surface 82a (FIG. 3) at the tip of the second portion 82 is preferably a mirror surface that is rounded (R-processed) and has as low a surface roughness as possible. Thereby, the slip with respect to the lead 201 can be improved, and wear of the lower surface 82a with time can be suppressed.

  The plate-like elastic body 80 has, for example, a plurality of second portions 82. The plurality of second portions 82 are arranged in a line at a predetermined interval (for example, a constant interval) in the arrangement direction of the plurality of leads 201 protruding from one side of the sealing resin 205 of the semiconductor device 200 placed on the knockout 10, And they are arranged parallel to each other.

  The second portions 82 are arranged at intervals between the sandwiching portions 42 so as not to overlap any sandwiching portion 42 in plan view. Therefore, each second portion 82 can be elastically deformed up and down without interfering with each clamping portion 42. More specifically, this elastic deformation is generally a swivel motion about the swivel portion 83 at the boundary between the first portion 81 and the second portion 82.

  As shown in FIG. 1, each second portion 82 protrudes toward the die 20 from the die 20 side surface of the holding portion 42 of the pressing member 40, that is, the lower end surface of the holding portion 42.

The pressing member 40 is suspended and held by the punch plate 60 via the pressing member guide 45 and the retaining portion 46.
The punch plate 60 is formed with an insertion hole 63 that vertically penetrates the punch plate 60.
The pressing member guide 45 is a columnar body that is long in the vertical direction. The pressing member guide 45 is inserted into the insertion hole 63, and a lower end portion thereof is fixed to the upper surface of the pressing member 40 below the insertion hole 63.
A retaining portion 46 is fixed to the upper end of the pressing member guide 45. The retaining portion 46 is formed in a size and shape that cannot enter the insertion hole 63. Therefore, the retaining portion 46 is prevented from moving below the upper surface of the punch plate 60. That is, the pressing member guide 45 and the pressing member 40 are prevented from falling off the punch plate 60.

  The lower end of the compression coil spring 47 is fixed to the upper surface of the retaining portion 46. The upper end of the compression coil spring 47 is fixed to the upper mold holder 70 or the press device. The compression coil spring 47 urges the retaining portion 46, the pressing member guide 45 and the pressing member 40 downward by its elastic force.

A pressing member stopper 48 is fixed to the lower surface of the main body 41 of the pressing member 40. When the upper die is lowered, the pressing member stopper 48 contacts the upper surface of the die plate 30 before the lower dead center stopper 61 contacts the upper surface of the die plate 30 to stop the lowering of the pressing member 40. .
Even after the pressing member stopper 48 comes into contact with the upper surface of the die plate 30, the upper die is lowered. At that time, the pressing member 40, the pressing member stopper 48, the pressing member guide 45, and the retaining portion 46 rise relative to the punch plate 60 against the urging force of the compression coil spring 47. At this time, the pressing member guide 45 is guided by the insertion hole 63.

  At the same time as or immediately before the pressing member stopper 48 comes into contact with the upper surface of the die plate 30 to stop the lowering of the pressing member 40, the lower end surface of the holding portion 42 of the pressing member 40 and the upper end surface 22 of the die 20. As a result, the leading end 202 of the lead 201 is clamped.

  Next, a method for manufacturing the semiconductor device according to the present embodiment will be described. This manufacturing method includes a step of cutting the tip portion 202 by shearing between the die 20 and the punch 50 in a state where the tip portion 202 of the external lead (lead 201) of the semiconductor device 200 is sandwiched between the die 20 and the pressing member 40. And a step of separating the die 20 and the pressing member 40 from each other. The pressing member 40 is provided with a plate-like elastic body 80 that protrudes toward the die 20 from the surface of the pressing member 40 on the die 20 side. When the external lead is sandwiched between the die 20 and the pressing member 40, the plate-like elastic body 80 is pushed by the die 20 and elastically deformed to the opposite side of the die 20. By separating the die 20 and the pressing member 40 from each other, the plate-like elastic body 80 is elastically returned to the die 20 side, and the tip 202 that has become the cutting waste 203 by cutting is pressed by the plate-like elastic body 80 and the die. You can get away from 20. Details will be described below.

  First, a semiconductor chip and a lead frame are prepared.

The semiconductor chip can be created in the following manner.
First, an element isolation film is formed on a semiconductor substrate. Thereby, the element formation region is separated. The element isolation film is formed using, for example, the STI method, but may be formed using the LOCOS method. Next, a gate insulating film and a gate electrode are formed on the semiconductor substrate located in the element formation region. The gate insulating film may be a silicon oxide film or a high dielectric constant film (for example, a hafnium silicate film) having a higher dielectric constant than that of the silicon oxide film. When the gate insulating film is a silicon oxide film, the gate electrode is formed of a polysilicon film. When the gate insulating film is a high dielectric constant film, the gate electrode is formed of a laminated film of a metal film (for example, TiN) and a polysilicon film. When the gate electrode is formed of polysilicon, a polysilicon resistor may be formed on the element isolation film in the step of forming the gate electrode.

  Next, source and drain extension regions are formed in the semiconductor substrate located in the element formation region. Next, sidewalls are formed on the sidewalls of the gate electrode. Next, impurity regions serving as a source and a drain are formed in a semiconductor substrate located in the element formation region. In this way, a MOS transistor is formed on the semiconductor substrate.

  Next, a multilayer wiring layer is formed on the element isolation film and the MOS transistor. An electrode pad is formed on the uppermost wiring layer. Next, a protective insulating film (passivation film) is formed on the multilayer wiring layer. An opening located on the electrode pad is formed in the protective insulating film.

  Thereafter, the wafer produced by the above process is separated into pieces by dicing. In this way, a semiconductor chip can be obtained.

  On the other hand, as shown in FIG. 6A, the lead frame 300 includes a plurality of leads 302 connected to each other by tie bars 301, a die pad (not shown) on which a semiconductor chip is mounted, and a connecting portion 303. And a frame portion 304 that suspends and holds the tie bar 301. The outer lead, that is, the lead 201 is a part of the lead 302.

  A semiconductor chip is mounted and bonded onto the die pad of such a lead frame 300. Next, the electrodes of the semiconductor chip and the leads 302 are electrically connected by wire bonding. Next, the base ends of the semiconductor chip, die pad, bonding wire, and lead 302 are sealed inside with a sealing resin 205. In this state, as shown in FIG. 6A, the leading end side of the lead 302, that is, the outer lead (lead 201) protrudes laterally from the side surface of the sealing resin 205.

  Next, the tie bar 301 and the lead 302 are separated from the frame part 304 by cutting the connecting part 303. Next, the outer lead (lead 201) is bent into a gull wing shape (FIG. 6B).

  Next, the tip 201 of the outer lead (lead 201) and the tie bar 301 are cut off from the base end side (the side closer to the sealing resin 205) of the lead 201 by cutting, thereby forming the lead 201 into a predetermined shape (see FIG. 6 (c)).

  Hereinafter, this cutting process will be described in detail with reference to FIGS.

  First, the semiconductor device 200 in which the leads 201 are bent into a gull wing shape is placed on the upper surface of the knockout 10. Thereafter, the upper die is started to be lowered from the top dead center by the press device.

  As described above, the relative positional relationship among the upper mold holder 70, the punch 50, the punch plate 60, and the bottom dead center stopper 61 is substantially constant. That is, as the upper mold holder 70 moves up and down, the punch 50, the punch plate 60, and the bottom dead center stopper 61 also move up and down integrally with the upper mold holder 70.

  When the upper die starts to descend, the retaining portion 56 is pressed against the upper surface of the punch 50 by the urging force of the compression coil spring 57, and the retaining portion 46 is urged by the urging force of the compression coil spring 47. It is pressed against the upper surface (see FIG. 1).

After that, as shown in FIG. 4A, first, the pressing pin 55 provided on the punch 50 comes into contact with the upper surface of the sealing resin 205, and the floating of the semiconductor device 200 is restricted.
Thereafter, the tip of the second portion 82 of the plate-like elastic body 80 comes into contact with the upper surface of the tip portion 202 of the lead 201.

As shown in FIG. 4 (b), the upper mold continues to descend. During the lowering, the plate-like elastic body 80 is deformed starting from the bent portion 83. The magnitude of the load required to deform the plate-like elastic body 80 starting from the bent portion 83 is set to be sufficiently smaller than the load required to deform the lead 201. Therefore, the upper mold moves downward while elastically deforming the plate-like elastic body 80 so that the second portion 82 pivots upward from the bent portion 83 as a starting point.
That is, by sandwiching the lead 201 between the die 20 and the pressing member 40, the plate-like elastic body 80 is pressed by the die 20 and elastically deformed to the opposite side of the die 20.
The elastic deformation of the plate-like elastic body 80 continues until the second portion 82 protrudes downward from the lower surface of the holding portion 42 of the pressing member 40 (FIG. 4C).

Here, the sealing resin 205 of the semiconductor device 200 is pressed down by the pressing pins 55. Therefore, the semiconductor device 200 is prevented from moving upward on the knockout 10 by the plate-like elastic body 80 pushing the lead 201 downward.
Since the pressing pin 55 is biased downward by the compression coil spring 57 and can move relatively upward with respect to the punch 50, an excessive load is not applied to the sealing resin 205 from the pressing pin 55. It is like that.
In this embodiment, the pressing pin 55 protrudes from the insertion hole 58 of the punch 50. However, since the pressing pin 55 only needs to be able to suppress the floating of the semiconductor device 200 from the knockout 10, the upper mold Depending on the difference in structure, the installation mode of the pressing pin 55 may be changed as appropriate.

  Further, in the process in which the plate-like elastic body 80 is elastically deformed as described above as the upper mold descends, the contact portion 52 of the punch 50 contacts the upper surface of the lead 201, so that the contact portion 52. And the knockout 10 hold the lead 201 (FIG. 4B).

  Even after the lead 201 is sandwiched between the contact portion 52 of the punch 50 and the knockout 10, the upper die is lowered so that the contact portion 52 presses the knockout 10 downward via the lead 201. Therefore, the compression coil spring (not shown) that supports the knockout 10 from below is compressed and elastically deformed, and the semiconductor device 200 is lowered together with the punch 50, the pressing member 40, and the knockout 10 (FIG. 4C). As a result, the die 20 rises relative to these.

Here, at the same time as or immediately after the lower surface of the tip portion 202 of the lead 201 contacts the upper end surface 22 of the die 20, the pressing member stopper 48 contacts the upper surface of the die plate 30. Descent stops.
Further, at the same time as or immediately before the lower surface of the tip portion 202 of the lead 201 and the upper end surface 22 of the die 20 are in contact with each other, the lower surface of the holding portion 42 of the pressing member 40 is brought into contact with the upper surface of the tip portion 202 of the lead 201. Touch.
Thus, the tip portion 202 of the lead 201 is clamped by the clamping portion 42 of the pressing member 40 and the upper end surface 22 of the die 20 before the tip portion 202 is cut in the process of lowering the upper die ( FIG. 4 (c)).
The lower surface of the holding portion 42 of the pressing member 40 and the upper end surface 22 of the die 20 maintain a clearance that is equal to or slightly smaller than the plate thickness of the lead 201 (about several μm), so that the tip of the lead 201 202 is sandwiched from above and below.

After the lowering of the pressing member 40 stops, the pressing member 40 is urged downward by the compression coil spring 47 via the retaining portion 46 and the pressing member guide 45 while the position in the height direction is kept constant. The
Even after the lowering of the pressing member 40 stops, the upper mold continues to descend. For this reason, the compression coil spring 47 is gradually compressed and elastically deformed, and the semiconductor device 200 continues to descend together with the upper mold holder 70, the punch plate 60, the punch 50, the pressing pin 55 and the knockout 10.

In the descending process, the die 20 is raised relative to the punch 50 as shown in FIG. For this reason, the tip portion 202 of the lead 201 is cut by shearing by the cooperation of the contact portion 52 of the punch 50 and the die 20.
By this cutting, the distal end portion 202 is separated from the proximal end portion of the lead 201 to become cutting waste 203.

  Here, the cutting waste 203 is sandwiched between the lower surface of the sandwiching portion 42 of the pressing member 40 and the upper end surface 22 of the die 20. For this reason, it can suppress reliably that the cutting waste 203 scatters.

  The lowering of the upper die continues until the upper die reaches the bottom dead center, that is, until the bottom dead center stopper 61 contacts the upper surface of the die plate 30. After the upper mold reaches the bottom dead center, the upper mold starts to rise.

  Thereafter, the operation until the upper mold reaches the top dead center is performed in the reverse order of the operation until the upper mold reaches the bottom dead center from the top dead center, except for the points described below. .

  First, as shown in FIG. 5B, the semiconductor device 200 rises together with the punch 50 and the knockout 10, but the cutting waste 203 continues to be held between the holding portion 42 of the pressing member 40 and the die 20.

The compression coil spring 47 is restored by further raising the upper die. Then, after the upper surface of the punch plate 60 contacts the lower surface of the retaining portion 46, the pressing member 40 starts to rise together with the punch plate 60. For this reason, the cutting waste 203 is released from the clamping state between the pressing member 40 and the die 20.
Until now, the plate-like elastic body 80 has been elastically deformed by being pressed upward by the die 20 through the cutting waste 203, but at the same time as the cutting waste 203 is released from the sandwiched state, the plate-like elastic body 80 is elastic. The body 80 is elastically restored. That is, the plate-like elastic body 80 is elastically restored so that the second portion 82 pivots downward from the bent portion 83 as a starting point.
By this operation, the cutting waste 203 is pushed out by the second portion 82 so as to be removed downward, and discharged to the outside of the lower mold through the discharge hole 32 (FIG. 5C).
That is, after cutting the tip portion 202, the die 20 and the pressing member 40 are separated from each other, whereby the plate-like elastic body 80 is elastically returned to the die 20 side, and the tip portion 202 that has become cutting waste 203 by cutting is plate-like. The elastic body 80 can be removed from the pressing member 40 and the die 20.
At this time, the positional relationship between the die 20 and the plate-like elastic body 80 is set so that the second portion 82 elastically returns without interfering with the die 20. For this reason, the 2nd part 82 can remove the cutting waste 203 smoothly.
At this time, since the end portions 202 are connected to each other via the tie bars 301, the cutting waste 203 is dropped even when the second portion 82 pushes the tie bar 301 located between the end portions 202. Can be made.

  From the viewpoint of the discharge performance of the cutting waste 203, the plate-like elastic body 80 preferably has the following shape.

First, the longer the protruding length L (FIG. 3) of the plate-like elastic body 80 from the lower surface of the holding portion 42 of the pressing member 40 is, the more the cutting waste 203 is discharged by the plate-like elastic body 80. However, if the protruding length L is excessively long, the plate-like elastic body 80 and the die 20 are used when the lead cutting device 100 is idled (an operation in which the upper die is lowered without disposing the semiconductor device 200 on the knockout 10). Can interfere with these parts and cause problems such as excessive wear of these parts.
For these reasons, the protrusion length L is at least equal to or greater than the plate thickness of the lead 201 and does not interfere with the elastic plate member 80 and the die 20 when the upper die reaches the bottom dead center during the blanking operation. preferable.
The protrusion length L is 0.15 mm or more and 0.45 mm or less. Specifically, the protrusion length L can be set to, for example, about 0.2 mm.

Further, the pressing position of the cutting waste 203 by the plate-like elastic body 80 is such that the cutting waste 203 is rotated at the time of discharge as much as possible in order to prevent the cutting waste 203 from rotating. In the middle part).
In FIG. 2, it is preferable that the plurality of second portions 82 be arranged symmetrically in the horizontal direction with respect to the center line C, and this also prevents the cutting waste 203 from rotating during discharge. it can.

  The plate-like elastic body 80 is desired to be able to smoothly and repeatedly bend starting from the bent portion 83. If the bending angle of the bending portion 83 is too small, a load that buckles the plate-like elastic body 80 acts on the plate-like elastic body 80, resulting in an adverse effect of the smooth bending operation of the plate-like elastic body 80. For this reason, the angle of the bent portion 83, that is, the angle α (FIG. 3) formed by the first portion 81 and the second portion 82 is preferably, for example, 135 ° or more.

  From the viewpoint of strength, the plate-like elastic body 80 preferably has the following shape.

First, the load applied to the lead 201 from the plate elastic body 80 increases as the load required for the elastic elastic deformation of the plate elastic body 80 increases. When this load is large, the lead 201 is deformed, and as a result, the outer shape of the lead 201 may be defective.
For this reason, it is preferable that the load required for the plate-like elastic body 80 to undergo bending elastic deformation is small so that substantial deformation of the lead 201 can be suppressed.

Here, for example, a semiconductor device 200 (144 pin QFP (Quad Flat Package) in which 36 leads 201 protrude from each side of the sealing resin 205, the plate thickness of the lead 201 is 0.125 mm, and the width of the lead 201 is 0.20 mm. ) Package) will be described.
In this case, the bending elastic deformation load of the plate-like elastic body 80 that elastically deforms in contact with the lead 201 protruding from one side of the sealing resin 205 is set to 0.3 kgf or less, thereby suppressing the defect of the outer shape of the lead 201. it can. That is, as shown in FIG. 2, when a plate-like elastic body 80 having three second portions 82 corresponding to one side of the semiconductor device 200 is disposed, the bending elastic deformation loads of these three second portions 82 are added together. The value may be set to 0.3 kgf or less.
Needless to say, the semiconductor device 200 to be processed in this embodiment is not limited to this example.

Since the plate-like elastic body 80 is repeatedly bent and elastically deformed with the bent portion 83 as a starting point, there is a possibility of fatigue failure. Stainless steel, which is a general leaf spring material, has a fatigue limit of about 20 kgf / mm ² for bending deformation, and the bending stress acting on the leaf spring material, that is, the plate-like elastic body 80 is preferably designed to be less than this value. .

  As an example of conditions that satisfy these conditions, as shown in FIG. 2, when a plate-like elastic body 80 having three second portions 82 corresponding to one side of the semiconductor device 200 is disposed, the material of the plate-like elastic body 80 is used. Is stainless steel, and the width of the second portion 82 is 2.0 mm, the length is 6.0 mm, and the plate thickness is 0.2 mm.

  Next, a preferable shape of the die 20 will be described.

If the length of the upper end surface 22 of the die 20 (the length in the direction along the longitudinal direction of the tip portion 202 of the lead 201) is too short, it becomes difficult to hold the tip portion 202 and the strength of the die 20 is insufficient. From this, chipping of the cutting edge part (the upper end part of the die 20) is likely to occur.
On the other hand, if the length of the upper end surface 22 of the die 20 is too long, the cutting waste 203 tends to remain on the die 20.
For this reason, it is preferable to design to the dimension which the cutting waste 203 can fall with dead weight.
Specifically, for example, the length of the upper end surface 22 of the die 20 is preferably an example of 0.15 mm or more and 0.30 mm or less. Specifically, the length of the upper end surface 22 of the die 20 can be set to, for example, about 0.2 mm.
By doing so, the tip 202 can be held with a sufficient holding force, and the cutting waste 203 can be easily discharged.

Moreover, if the inclination angle of the inclined surface 21 of the die 20 is too steep, the cutting waste 203 slides down on the inclined surface 21 and the cutting property of the cutting waste 203 is improved. In this case as well, the width of the die 20 is increased. It becomes small and leads to the strength reduction of the die 20. Therefore, it is preferable that the inclination angle β (FIG. 3) of the inclined surface 21 is as large as possible within a range having sufficient strength.
Specifically, for example, the inclination angle β of the inclined surface 21 of the die 20 is a preferred example of 45 ° or more and 60 ° or less.
However, if there is no problem in the strength of the die 20, it is preferable that the inclination angle β is large.

According to the embodiment described above, first, the die 20 is sandwiched between the die 20 and the pressing member 40, so that the plate-like elastic body 80 is elastically deformed to the side opposite to the die 20, and the die 20. And the punch 50 cut the tip 202 of the lead 201. Thereafter, the die 20 and the pressing member 40 are separated from each other, whereby the plate-like elastic body 80 is elastically returned to the die 20 side, and the tip end portion 202 that has become cutting waste 203 by cutting is pressed by the plate-like elastic body 80. And can be removed from the die 20.
That is, since the tip portion 202 of the lead 201 is cut while the lead 201 is sandwiched between the die 20 and the pressing member 40, scattering of the cutting waste 203 can be suppressed. The cutting waste 203 can be removed from the pressing member 40 and the die 20 and discharged by a simple configuration in which the plate-like elastic body 80 is provided on the pressing member 40.
Therefore, the scattering of the cutting waste 203 and the remaining of the cutting waste 203 in the apparatus can be suppressed with a simple configuration, and the deterioration of processing accuracy due to the remaining cutting waste 203 can be reduced. Stable quality semiconductor device 200 can be manufactured.

In addition, in the technique of patent document 1, although the scattering prevention body, the splash prevention body, and the external force addition body are suppressing the scattering of cutting waste, it still cannot necessarily prevent scattering of cutting waste reliably.
Since the external force addition body of patent document 1 is provided in the punch holder, it descends vigorously as the upper die descends. Therefore, a very large external force is applied to the lead from above. Thereby, at the time of cutting of the lead, the lead is deformed so as to bend downward from the cut point. Since the lead is cut in a bent state, the elastic force of the lead is instantaneously released at the time of cutting, and the cutting waste is scattered violently. The scattering direction of the cutting waste is highly random (low reproducibility).
If the cutting dust scatters, the cutting hole is not easily maintained in the discharge hole and the cutting hole is clogged in the discharge hole, or the lower die is in contact with the upper mold stopper member. There is a possibility of getting on board. In the latter case, the processing accuracy is deteriorated and the mold is damaged.

  On the other hand, in the case of the present embodiment, the elastic recovery of the plate-like elastic body 80 proceeds in synchronization with the rise of the upper mold, so that the cutting waste 203 is pushed downward by the second portion 82 of the plate-like elastic body 80. Therefore, it falls down with a reproducible operation. Therefore, scattering of the cutting waste 203 can be reliably suppressed.

  In the above embodiment, an example in which the elastic body has a plate shape (plate spring) has been described, but the elastic body may have other forms. The elastic body may be, for example, a pin shape or a compression coil spring.

DESCRIPTION OF SYMBOLS 10 Knockout 20 Die 21 Inclined surface 22 Upper end surface 30 Die plate 31 Opening 32 Ejection hole 40 Holding member 41 Main body part 42 Holding part 45 Holding member guide 46 Retaining prevention part 47 Compression coil spring 48 Holding member stopper 50 Punch 51 Main body part 52 Contact Portion 53 Retaining portion 55 Holding pin 56 Stopping portion 57 Compression coil spring 58 Insertion hole 60 Punch plate 61 Bottom dead center stopper 62 Opening 63 Insertion hole 70 Upper mold holder 80 Plate-like elastic body 81 First portion 82 Second portion 82a Lower surface 83 Bending portion 84 Bolt 100 Lead cutting device 200 Semiconductor device 201 Lead 202 Tip portion 203 Cutting waste 205 Sealing resin 300 Lead frame 301 Tie bar 302 Lead 303 Connecting portion 304 Frame portion

Claims (5)

Cutting the tip by shearing with the die and the punch in a state where the tip of the external lead of the semiconductor device is sandwiched between the die and the pressing member;
Separating the die and the pressing member;
Have
The pressing member is provided with an elastic body that protrudes toward the die side from the die side surface of the pressing member,
When sandwiching the tip portion between the die and the pressing member, the elastic body is pushed by the die and elastically deformed to the opposite side of the die,
By separating the die and the pressing member, the elastic body is elastically returned to the die side, and the tip portion that has become cutting waste by the cutting can be removed from the pressing member and the die by the elastic body. A method for manufacturing a semiconductor device. The elastic body is a leaf spring,
A first portion formed in a flat plate shape and fixed to the pressing member;
A second portion formed in a flat plate shape, integrally formed with the first portion, bent with respect to the first portion, and projecting toward the die side from the die side surface of the pressing member;
A method for manufacturing a semiconductor device, comprising: The pressing member has a plurality of sandwiching portions that face the die and sandwich the tip portion between the die and the die.
3. The method of manufacturing a semiconductor device according to claim 1, wherein the elastic body is arranged at an interval between the plurality of sandwiching portions.   4. The method of manufacturing a semiconductor device according to claim 1, wherein a protruding length of the elastic body from the pressing member to the die side is 0.15 mm or more and 0.45 mm or less. 5. . A semiconductor device having an external lead is mounted so that the tip of the external lead protrudes; and
A die disposed adjacent to the mounting portion;
A pressing member sandwiched between the die by pressing the tip of the external lead against the die; and
A punch for cutting the tip by shearing in cooperation with the die;
An elastic body provided on the pressing member and projecting toward the die side from a surface of the pressing member on the die side;
Have
By sandwiching the external lead between the die and the pressing member, the elastic body is pressed by the die and elastically deformed to the opposite side of the die,
The lead cutting apparatus according to claim 1, wherein the elastic body is elastically returned to the die side by separating the die and the pressing member.

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