JP3802519B2 - Lead frame manufacturing method and manufacturing apparatus - Google Patents

Description

  The present invention relates to a lead frame manufacturing method and manufacturing apparatus, and more particularly to a method incorporating a removal process of metal burrs generated during punching.

  In recent years, electronic devices have been miniaturized and densified, and there is a great demand for miniaturization of semiconductor devices such as IC (Integrated Circuit) packages. For this reason, the number of pins of a semiconductor device and the fine pitch have been increased, and the width of each lead of the lead frame has been reduced accordingly. Examples of such an IC package include a surface mount type QFP (Quad Flat Package) and an SOP (Small Outline Package).

Here, a QFP type lead frame will be described as an example with reference to FIG. 2 of the present embodiment. Normally, when a plurality of leads are punched into a shape as shown in FIG. 2, the metal material is plastically deformed and pulled by the punch, and a droop m and a metal burr (burrage) n are generated (see FIG. 9). This metal burr may cause a dimensional error, a deformation, or a bonding failure. Furthermore, even if the burrs are crushed in the burr pressing process, the burrs fall down and fall asleep, and the lead interval may be narrowed. Further, when the metal burr is removed and a metal piece is generated, there is a problem that a short circuit is caused and the reliability of the product is lowered. In order to remove the metal burrs, for example, when the lead frame material is a copper alloy, a method such as chemical etching that uses a ferric chloride solution to corrode the surface and remove unnecessary portions has been conventionally used. . On the other hand, as a method of removing the resin burr generated after the inner lead is sealed with the semiconductor chip by the sealing resin (see FIG. 10), a method of sliding a rotating brush or the like on the lead portion is known. (See Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 1-164550 (Claim 1, FIG. 2) JP-A-8-55763 (Claim 1, paragraph number [0017], FIG. 1)

  As described above, etching was the mainstream method for removing metal burrs such as the inner lead portion and outer lead portion that are generated during press processing of the lead frame. However, according to conventional methods such as etching, only metal burrs are used. Instead, the lead itself other than the metal burr is also polished, and the flatness of the lead is not ensured. Further, the problem has been pointed out that the surface of the lead is rough and the influence on the plating occurs.

Further, depending on the conventional method using a rotating brush, there is a problem that even if resin burrs can be removed, metal burrs cannot be removed.
In order to solve the above problems, an object of the present invention is to provide a lead frame manufacturing method and a manufacturing apparatus capable of removing metal burrs generated during punching without deforming or scratching the lead itself. And

In order to achieve the above object, a lead frame manufacturing method according to a first aspect of the present invention includes a plurality of leads electrically connected to a semiconductor chip, and the semiconductor chip is placed on the lead in a sealed state. A manufacturing method of a lead frame used in a semiconductor device to be stopped, wherein a plurality of flexible linear bodies are implanted after a punching process of punching a lead frame material made of a metal plate with a press to form a shape of the lead frame. a brush formed in a circular cylindrical is, deburring means and a brush drive means for driving the brush, by rotating the brush in a state of sliding contact with the brush to the lead portion, the punching step A deburring step for removing metal burrs generated in the lead portion formed at times, and the flexible linear body is an aromatic polyamide fiber having heat resistance. , And summarized in that a uniform containing fine abrasive grains consisting of fineness of diamond abrasive grains in the range of # 1500 to # 4000.

The lead frame manufacturing method according to claim 2 is characterized in that, in the configuration of the lead frame manufacturing method according to claim 1, the brush is rotated at 1500 to 3000 rpm .

  The lead frame manufacturing method according to a third aspect is characterized in that, in the configuration of the lead frame manufacturing method according to the first or second aspect, the deburring means includes a plurality of the brushes.

  The lead frame manufacturing method according to claim 4, wherein in the lead frame manufacturing method according to any one of claims 1 to 3, the flexible linear body planted in the brush in the deburring step. When removing the metal burrs from the lead part, the tip part is inclined with respect to the lead part in a posture inclined at a predetermined angle from the direction perpendicular to the lead frame in a direction opposite to the sliding direction. The point is to contact.

  According to a fifth aspect of the present invention, in the lead frame manufacturing method according to the fourth aspect, the brush is generally radially outward from an axial center portion where the flexible linear body is formed at the center of the brush. The flexible linear body is planted by being inclined at a predetermined angle from a radial direction of the wheel brush to a direction opposite to the rotation direction of the wheel brush. This is the gist.

According to a sixth aspect of the present invention, in the lead frame manufacturing method according to the third aspect , the deburring means is not parallel to the first brush that rotates in a predetermined direction and the rotation axis of the first brush. And a second brush having a rotation axis, wherein an angle formed between the rotation axis of the first brush and the rotation axis of the second brush is in a range of 60 degrees to 120 degrees .

According to a seventh aspect of the present invention, in the lead frame manufacturing method according to any one of the first to sixth aspects, above the deburring means, a means for cleaning metal burrs removed during the deburring process. As a subsequent process of the deburring step, the lead frame is subjected to a first cleaning as a preliminary cleaning with a first cleaning rod and a second cleaning bath as a second cleaning as a main cleaning. subjected to cleaning, and subject matter to migrate into subsequently by hot-air drying process.

The lead frame manufacturing apparatus according to claim 8 is a manufacturing apparatus for realizing the lead frame manufacturing method according to any one of claims 1 to 6 , wherein the lead frame manufacturing apparatus is in sliding contact with a lead portion of the lead frame. The gist of the invention is to provide a deburring means having a brush for removing metal burrs generated during punching.

  According to the present invention, metal burrs generated during punching can be removed without deforming or scratching the lead itself.

Hereinafter, an embodiment embodying a lead frame manufacturing method and manufacturing apparatus according to the present invention will be described with reference to FIGS.
FIG. 1 is a plan view of an entire continuous lead frame 1 manufactured in the present invention, and FIG. 2 is an enlarged view of one lead frame 1 shown in FIG. The lead frame 1 of the present embodiment will be described by taking the lead frame 1 used for a QFP type IC package as an example.

  The lead frame 1 is generally manufactured by primary stamping, plating, and secondary stamping processes. First, copper strips are sequentially pressed and punched into the shape of the lead frame 1 in a plurality of steps of primary stamping, which is a punching step. A large number of lead frames 1 are formed on a blank copper strip in a horizontal (width direction) by one to several rows and vertically (conveying direction) and punched out by stamping while being sequentially fed to a press. Here, the deburring process and the cleaning process of the present invention, the subsequent cleaning process, and the drying process are performed. These steps will be described in detail later. Thereafter, in the plating step, the inner side end portion of the inner lead is subjected to Ag plating in order to improve the adhesion of the bonding surface during bonding. Finally, it is shaped and completed by secondary stamping. In addition, the process of this embodiment is an example, Comprising: Even if this invention is a process different from the said process, what is necessary is just to include a predetermined | prescribed deburring process. For example, in order to improve the adhesion of Ag plating in the plating step, the lead may be Cu plated before Ag plating.

  In the present embodiment, as shown in FIG. 1, a lead frame 1 in which lead portions 2 are formed in a vertical row on a copper strip having a width w of about 50 mm will be described as an example. FIG. 2 is a diagram showing a dotted line portion of the lead frame 1 in FIG. As shown in FIG. 2, each lead frame 1 is provided with a suspension lead 23 from four corners toward the center, and a substantially square die pad 24 is horizontally supported by the suspension lead 23 in the center. Opposing the four sides around the die pad 24, a lead portion 2 is formed, and a large number of leads 20 are arranged in a generally comb shape. For example, in this embodiment, for the sake of explanation, the number of leads 20 shown in FIG. 2 is small, but actually, for example, a fine-pitch of 200 pins or more such as a 256-pin type is manufactured. A portion of the lead 20 facing the die pad 24 is configured as an inner lead 21 that is electrically connected to the semiconductor chip 11, and the outer side of the lead 20 is mounted on an external substrate (not shown). Outer leads 22 for extending are provided. A straight dam bar 25 is provided on the inner base portion of the outer lead 22 in a direction orthogonal to the outer lead 22. The lead frame 1 of the present embodiment is completed in the above state.

  Here, FIG. 3 is a schematic diagram showing a deburring process and a cleaning process, and a cleaning process and a drying process, which are subsequent processes, in the manufacturing process of the lead frame in the manufacturing apparatus 40. The lead frame 1 that has completed the primary stamping process is once wound around the supply-side auto reel 41 and accommodated. The lead frame 1 once wound around the supply-side auto reel 41 is sandwiched between a pair of transport rollers 47 in the drying process. The transport roller 47 is rotated by a driving unit (not shown) to transport the lead frame 1 to the right in FIG. 3 as a transport unit. The conveyance speed to the deburring process can be preferably carried out at a speed of approximately 10 to 20 mm / s. In this embodiment, the lead frame 1 is supplied at 10 mm / s. It can be changed as appropriate. The supplied lead frame 1 is placed on the transport path R, and the deburring means 42 is disposed along the back surface of the lead frame 1 placed on the transport path R. Further, a liquid shower device 49 is disposed above the deburring means 42 as means for cleaning the metal burrs removed during the deburring process. The lead frame 1 after the deburring process and the cleaning process has an infinite number of removed metal burr dust and the like. Therefore, as a subsequent process, the cleaning is performed on the lead frame 1 with the cleaning basket 45 as the first cleaning, the second cleaning as the main cleaning is performed with the cleaning basket 46, and then the drying process is performed with hot air or the like. Transition. The cleaning liquids used for the first cleaning and the second cleaning may be the same or different, but both include water, hot water, a hydrocarbon solvent, or a cleaning agent. Can be used. The lead frame 1 after the drying process is once wound up by the winding-side auto reel 48 and proceeds to the next process.

  Next, the configuration of the deburring means 42 in the deburring process will be described in detail. Normally, when punching a copper strip whose lead frame is a lead frame material, the copper strip is plastically deformed by the punch and pulled in the punching direction, and the lead portion 2 (lead portion 2 of the lead portion 2) of the lead frame 1 after punching is processed. A metal burr n is formed on the back side (lower side in FIG. 9). In the deburring process in the present embodiment for removing the metal burrs generated during the punching process, the brush in a sliding contact state rotates from the lower surface to the lead portion 2 where the metal burrs are generated in the lead frame 1 that is automatically conveyed. Metal burrs generated in the lead portion 2 are scraped off.

  As shown in FIGS. 4 and 5, the deburring means 42 includes a wheel-type first brush 43 and a second brush 44. The first brush 43 can rotate about the rotation axis a, and the second brush 44 can rotate about the rotation axis b in the direction of the arrow on the page. Here, a solid arrow indicates a sliding direction in which the tip of the brush slides with the lead frame 1. That is, the rotation direction of the first brush 43 and the second brush 44 is the angle θ between the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 at the tip of each brush. The direction of sliding from the inner region H1 side to the outer region H2 side (FIG. 5) (solid arrow). Further, the first brush 43 and the second brush 44 are arranged such that an angle θ formed by the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 is 90 degrees. (Fig. 3). Further, the center line c of the angle θ formed by the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 is the conveyance direction of the lead frame 1 (the left direction in FIG. 5, in FIGS. 4 and 5). It is orthogonal to the dashed arrow). Both the first brush 43 and the second brush 44 are collectively referred to as both brushes (hereinafter, the first brush 43 and the second brush 44 are collectively referred to as “brush” when both brushes are shown without particular distinction). Is connected to brush driving means such as a motor that rotates at a predetermined rotational speed (not shown). The rotation speed is preferably, for example, 1500 to 3000 rpm from the vibration of the hair, centrifugal force, temperature rise, and the like. In this embodiment, a brush rotating at a rotation speed of about 3000 rpm is slidably contacted, but the rotation speed is limited to this. However, it can be appropriately changed depending on conditions.

  Next, the configuration of the first brush 43 and the second brush 44 will be described. FIGS. 6 to 8 are views showing the first brush 43 and will be described along these drawings. The configuration of the second brush 44 is the same. As shown in FIGS. 6 to 8, the first brush 43 and the second brush 44 are both tire-type wheel brushes, and a shaft member (not shown) connected to a brush driving means such as a motor at the center. ) Is inserted. Furthermore, a shaft core portion 52 made of metal or synthetic resin is provided outside the hole 51, and a large number of hairs 53, which are flexible linear bodies extending from the shaft core portion 52 toward the outer periphery, are implanted. . Further, as shown particularly well in FIG. 7, a large number of hairs 53 are implanted radially from the axial center portion 52 of the brush in a generally radial direction. More specifically, each hair 53 has a predetermined angle φ = in a direction opposite to the rotation direction of the brush with respect to a straight line d extending in the radial direction from the axis center o (coincident with the rotation axis a) of the shaft core portion 52. It is planted at an angle of 15 degrees. FIG. 8 is a cross-sectional view taken along the line AA in FIG. 7 and impregnates the hair 53 planted at a high density and obliquely with a special resin as an epoxy resin layer 54 at an adhesive portion with the shaft core portion 52. It is fixed. For this reason, there is little movement of abnormal hair, and it is set as the structure which a polishing spot does not appear easily. When the brush rotates and slidably contacts with the lead frame 1, the bristle tip 53a appears as if the lead portion 2 is smooth with an appropriate pressing force in combination with the appropriate elasticity of the aramid fiber. The metal burr is scraped off from the surface of the lead portion 2 by rubbing. The amount of application at this time is preferably 1 to 3 mm, for example, and is 1 mm in the present embodiment, but is not limited to this range, and can be appropriately changed depending on conditions. In this embodiment, a wheel brush having a hole diameter d = 65 mm and an outer diameter D = 150 mm is used.

  The bristles of the first brush 43 and the second brush 44 are meta-type aromatic polyamide heat-resistant fibers, that is, aramid fibers. Aramid fibers are classified into “para-types” that have high strength and excellent heat resistance, and “meta-types” that have high flame resistance and heat resistance. In this embodiment, a meta-type aramid fiber is used. The aramid fiber is an organic synthetic fiber mainly composed of metaphenylenediamine and isophthalic acid chloride, and polymetaphenylene isophthalamide as a component. Chemically stable and spreadable benzene rings are connected to the meta-type continuously by amide bonds, so that existing synthetic fibers such as polyester and nylon (registered trademark) and fibers similar to natural fibers Maintains performance (strong elongation, elastic modulus, specific gravity, texture, color, etc.). For example, it does not melt in the air, and has both heat resistance that starts decomposition and carbonization for the first time at 400 ° C., and flame resistance and flame retardancy of 29 or more of the limiting oxygen index (LOI value). Therefore, by using an aramid fiber, it can be rotated at a higher speed than nylon (registered trademark) or the like, and work efficiency can be improved.

  Further, the aramid fiber of the present embodiment uniformly contains diamond abrasive grains having a fineness of # 3000 as fine abrasive grains for polishing. By containing this diamond abrasive grain, the fiber is more excellent in grinding force and durability. According to such fine abrasive grains, the metal powder generated by polishing also becomes fine, and the generation of relatively large metal pieces can be suppressed, so the occurrence of defective products such as short circuits caused by the mixing of metal pieces Can be eliminated.

(Operation) The configuration of the deburring means has been described in detail above. Next, the operation and the deburring method will be described.
The lead frame 1 after the primary stamping is illustrated on the lead portion 2 (metal burr generation portion) of the lead frame 1 that has been automatically conveyed on the conveyance path R by the above-described conveyance means (FIG. 3) before plating. The first brush 43 and the second brush 44, which are rotated at a predetermined number of rotations by the drive motor that does not, are in sliding contact. At this time, the bristles 53a of the first brush 43 and the second brush 44 are rubbed so that the lead portion 2 is smooth, and the metal burr is scraped off the surface of the lead portion 2 (FIG. 7). Since the hair 53 is a flexible linear body, when contacting the lead portion 2, the middle portion of the hair is bent, and the metal burr is scraped off in a state where the tip portion 53 a is in contact with the lead portion 2. Thereafter, the hair tip 53a continuously slides repeatedly on the lead portion 2 one after another, and the burrs of the lead frame 1 are removed and polished. The lead portion 2 is first polished by the first brush 43 and then polished by the second brush 44 (FIG. 4). Here, since the angle formed by the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 is 90 degrees, the direction of polishing by the first brush 43 and the second brush The direction to be polished by 44 intersects, and metal burrs at any position can be polished from various directions. In particular, the effect is obvious when compared with the case where the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 are parallel on the lead frame.

  In addition, the first brush 43 and the second brush 44 are arranged from the inner region H1 of the angle between the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 at the tip of each brush. They are rotating in the direction of sliding toward the external region H2 (solid line arrows in FIGS. 4 and 5). Therefore, a force acts on the lead frame 1 in a direction in which the lead frame 1 is pressed toward the transport path R from above, so that the lead frame 1 is stably placed on the transport path R. Further, the lead frame 1 is prevented from being deformed inside by the mutual rotation of the first brush 43 and the second brush 44.

  Further, the lead frame 1 at the time of the deburring process as described above is simultaneously subjected to a cleaning process by the liquid shower device 49. During the deburring process, the metal particles of the metal burr scraped with the brush adhere to the lead frame 1 innumerably. The cleaning process by the liquid shower device 49 is necessary to efficiently remove the metal burrs while washing away the metal powder adhering to the lead frame 1. In other words, the liquid shower device 49 functions as a deburring / removal assist mechanism. Further, since wet processing is performed, there is an advantage that scratches are hardly generated on the lead frame 1 by cooling the hair tips and removing polishing debris to improve the removal performance of metal burrs and imparting lubricity.

  As described above, the lead frame 1 manufactured through a series of processes including the deburring process for removing the metal burrs, as shown in FIG. 10, the semiconductor chip 11 is then attached to the die pad 24 with the double-sided tape or adhesive. The metal wire 12 is connected to the surrounding inner lead 21 from the electrode of the semiconductor chip 11 by bonding or the like. The resin is sealed with the sealing resin 3 at a position (see FIG. 2) indicated by a two-dot chain line on the inner side of the dam bar 25. Or it may be capped with a ceramic or metal plate instead of a sealing resin and sealed with glass, welding, or the like. In any case, the semiconductor body 15 is formed by performing these sealing steps. Thereafter, the dam bar 25 is cut and the leads 20 are cut off.

In the present embodiment, the following effects can be obtained.
(1) As a method for removing metal burrs generated during punching, a method of polishing with a brush completely different from the conventional method was adopted. Thereby, metal burrs can be removed without deforming or scratching the lead itself. Furthermore, not only metal burrs caused by punching but also chipping burrs caused by mold scratches and the like can be similarly removed by polishing. Unlike conventional methods such as etching, leads other than metal burrs themselves are not corroded. In this embodiment, the surface roughness after polishing was Rz = 0.45 to 0.58, which was substantially equivalent to that of the unprocessed product. Also, the surface was not abnormal by SEM observation, and the metal burrs were effectively removed. Furthermore, there was no adverse effect on the adhesion of Ag plating or Cu plating.

  In the present embodiment, the flatness of the lead frame 1 can be ensured without deformation caused by polishing. In this embodiment, the lead shift (displacement in the horizontal direction) was a change of 15 μm at the maximum, but it could be determined that there was almost no deformation when judged from the measurement result of the outer shape on the chart (× 10).

  (2) Since the brush rotates in a sliding contact with the surface of the lead frame 1 while automatically transporting the lead frame 1, the metal burrs generated in the lead portion 2 are efficiently polished and removed by the rotation of the brush. Can do. In particular, the use of an aramid fiber with high heat resistance enabled high-speed rotation and increased work efficiency.

  (3) The bristles 53 to be planted on the brush are planted at a predetermined angle φ = 15 degrees from the radial direction of the shaft core portion 52 of the brush to the direction opposite to the rotation direction of the brush. That is, when sliding with the lead part 2, the bristle tip 53 a is not pierced perpendicularly to the lead part 2, but in a posture inclined in a direction opposite to the sliding direction from the direction perpendicular to the lead frame 1. It is in sliding contact with the lead frame 1. For this reason, the hair tip 53a is polished as if the lead portion 2 was stroked. For this reason, generation | occurrence | production of the damage | wound to lead frame 1 itself by grinding | polishing can be reduced.

  (4) The deburring means 42 includes a plurality of brushes including a first brush 43 and a second brush 44. Therefore, as compared with a single brush, the metal burr generation portion of the lead can be polished over a wider range at a time, which is more efficient.

  (5) The bristles 53 of the brush are composed of heat-resistant aramid fibers. Since aramid fibers are excellent in maintaining maintenance performance and dimensional stability at high temperatures, they have high durability when removing metal burrs, and can implement a burring removal step efficiently without unevenness. In addition, useless scratches or the like are not generated on the surface of the lead frame 1.

  (6) Since the brush bristle 53 contains fine # 3000 diamond abrasive grains uniformly, in combination with the elasticity of the brush bristle 53, an excessive stress is applied depending on the hardness of the diamond, More excellent polishing can be realized in which the metal burrs can be surely removed without causing unnecessary scratches and while preventing the generation of metal pieces. In addition, since the metal burrs are reliably removed by polishing without generating a large metal piece, a short circuit between the leads can be prevented, and a highly reliable lead frame 1 with high reliability can be manufactured.

The above embodiment may be changed to another embodiment (another example) as follows.
-You may comprise the wheel brush in the said embodiment as brushes, such as a cup brush, a channel brush, a plate brush, a bevel brush, and the belt-shaped brush which transplanted.

  In the above embodiment, the angle formed by the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 is 90 degrees, but is not limited to this. You may comprise freely so that a predetermined angle may be made within the range of 120 degree | times.

-You may arrange | position the 1st brush 43 and the 2nd brush 44 in the said embodiment so that it may become parallel on a lead frame.
In the above-described embodiment, the rotation directions of the first brush 43 and the second brush 44 are such that each tip portion of the brush has a rotation axis a of the first brush 43 and a rotation axis b of the second brush 44. Although the direction of sliding is defined as the direction of sliding from the inner region H1 side to the outer region H2 side, this rotational direction may be reversed. In other words, the removed metal burr may slide in the direction formed by the rotation axis a of the first brush 43 and the rotation axis b of the second brush 44 from the outer region H2 side to the inner region H1 side. Further, the rotation direction of the first brush 43 remains the same as in the above embodiment, while only the rotation direction of the second brush 44 is set as a direction sliding from the outer region H2 side to the inner region H1 side. good. On the contrary, the rotation direction of the second brush 44 is the same as that of the above embodiment, and only the rotation direction of the first brush 43 may be set as the direction of sliding from the external region H2 side to the internal region H1 side. .

-Although the deburring means 42 in the said embodiment was set as the structure which has two brushes, the 1st brush 43 and the 2nd brush 44, it may replace with this and may be comprised as a single brush.
-Although the deburring means 42 in the said embodiment was set as the structure which has the 1st brush 43 and the 2nd brush 44, this 1st brush 43 and the 2nd brush 44 are made into a pair, not only a pair but multiple pairs. It is good also as a structure provided with this brush. In this case, since the metal burrs of the lead portion 2 can be removed over a wider area at a time, the efficiency is good.

  In the above embodiment, the rotating brush is slidably contacted only with the back side surface of the lead frame to remove the metal burrs. However, as a method of removing the metal burrs by sliding the brush from both sides of the lead frame. Also good. In that case, the pair of brushes composed of the first brush 43 and the second brush 44 is placed on the upper side (upward direction in FIG. 3) of the lead frame 1 in the transport path, as in the above embodiment. Another pair may be provided along R. Alternatively, after the deburring process is performed from the back surface of the lead frame 1, the pair of brushes may be pressed again from the surface of the lead frame 1 to perform the deburring process.

  In the embodiment, the lead frame is automatically conveyed on the conveyance path R, so that the brush is in sliding contact with the lead frame. However, by moving the brush itself, It is good also as a structure made to slide with the flame | frame 1. FIG.

  In the above embodiment, the driving means for rotating the first brush 43 and the second brush 44 is the same, but the first brush 43 and the second brush 44 are provided with separate driving means. Also good.

In the embodiment described above, the brush hair 53 is a meta-type aramid fiber, but may be a synthetic fiber such as nylon (registered trademark) instead.
In addition, the hair 53 to be planted on the brush is planted by inclining at a predetermined angle φ = 15 degrees from the radial direction of the shaft core portion 52 of the brush to the direction opposite to the rotation direction of the brush. A range of 20 degrees is preferred. The angle is not limited to this angle, and the angle can be changed as appropriate depending on conditions.

  As fine abrasive grains for polishing, # 3000 diamond abrasive grains are used in the present embodiment, but # 1500 to # 4000 are preferable from the viewpoint of the state after polishing and efficiency. Depending on the shape, other abrasive grains can be selected. In addition, diamond is also preferable as the material of the fine abrasive grains, but other materials such as alumina can be mixed or replaced because of cost or the like.

  In place of the liquid shower device 49 in the above embodiment, an air blow device or an air suction device may be used. Alternatively, the brush itself may be immersed in a cleaning solvent, water, or the like. In this case, since wet processing is performed in the same manner as the liquid shower device, polishing waste can be removed when removing burrs, scratches are difficult, and a cooling effect is maintained, so that high working efficiency can be maintained.

  In the above-described embodiment, the lead frame 1 that has completed the primary stamping process is temporarily wound around the supply-side auto reel 41. Instead, the deburring process is performed as a line configuration directly connected from the primary stamping. The lead frame 1 may be supplied directly without using a reel. Similarly, with respect to the take-up side auto reel 48, in the above embodiment, the lead frame 1 which has been finished up to the drying step is temporarily wound around the take-up side auto reel 48, but directly to the next step without being taken up. You may comprise so that the lead frame 1 may be conveyed.

In the above embodiment, the QFP type semiconductor device has been described as an example. However, the semiconductor device can be applied to lead frames related to various other semiconductor devices.
In the embodiment, the copper alloy is taken as an example of the lead frame material, but the lead frame material is not limited to the Cu-based copper alloy, and Fe-based, SUS-based, or the like may be used.

  -A residual stress removal process may be further added after the deburring process in the said embodiment. In the deburring step, the lead frame 1 may be warped due to surface processing hardening or processing stress caused by brush polishing. Therefore, for example, if an annealing process is used in which the residual stress is removed at a certain temperature for a certain period of time and then gradually cooled, distortion of the lead frame after the deburring process can be prevented.

Next, the technical idea that can be grasped from the respective embodiments and other examples will be described below.
(Additional remark 1) The said deburring means is provided with the 1st brush which rotates in a predetermined direction, and the 2nd brush which has a rotating shaft which is not parallel to the rotating shaft of the said 1st brush, The said 1st brush The lead frame manufacturing method according to claim 3, wherein an angle formed between the rotation axis of the second brush and the rotation axis of the second brush is in a range of 60 degrees to 120 degrees. In the lead frame manufacturing method according to this configuration, the angle formed by the rotation axis of the first brush and the rotation axis of the second brush has a predetermined angle. That is, since the first brush and the second brush are not parallel, the portion polished by the first brush is further polished by the second brush from a direction different from the polishing direction of the first brush. For this reason, metal burrs generated at any position and direction on the lead frame can be efficiently removed.

(Supplementary note 2) The method of manufacturing a lead frame according to supplementary note 1, wherein an angle formed between the rotation axis of the first brush and the rotation axis of the second brush is 90 degrees.
(Supplementary Note 3) The rotation direction of the brush is a direction in which an angle formed by a direction in which the tip of the brush slides and a conveyance direction of the lead frame material to be conveyed is 90 degrees or less. The method for manufacturing a lead frame according to any one of claims 2 to 3, or appendix 1 to appendix 2. In the lead frame manufacturing method according to this configuration, a force that pushes back the lead frame in the direction opposite to the conveying direction is not applied by the rotation of the brush. On the contrary, since the rotation of the brush acts in the direction of promoting the automatic conveyance of the lead frame, there is an effect of preventing the automatic conveyance of the lead frame from being hindered.

  (Additional remark 4) As for the rotation direction of the said 1st brush and the said 2nd brush, each front-end | tip part of the said 1st brush and the said 2nd brush is the rotating shaft of the said 1st brush, and the said 2nd brush. The method of manufacturing a lead frame according to claim 3 or appendix 1 to appendix 3, characterized in that the direction is a direction of sliding from an inner region side to an outer region side of an angle formed by the rotation axis. In the lead frame manufacturing method according to this configuration, the lead frame 1 is automatically and stably conveyed to the lead frame 1 so as to be pressed against the conveyance path R by the rotation of the first brush and the second brush. Further, the lead frame 1 is deformed by each internal region side formed by the rotation axis of the first brush and the rotation axis of the second brush by the mutual rotation of the first brush and the second brush. Is preventing.

  (Additional remark 5) The centerline of the angle | corner which the rotation axis of the said 1st brush and the rotation axis of the said 2nd brush make is a direction orthogonal to the conveyance direction of the said lead frame, The additional remark 1 thru | or characterized by the above-mentioned. The method for manufacturing a lead frame according to any one of appendix 5.

  (Additional remark 6) The said flexible linear body inclines in the axial center part of the said wheel brush so that the said predetermined angle may be 10-20 degree | times, and is planted. Lead frame manufacturing method.

  (Additional remark 7) The said fine abrasive grain contains a diamond abrasive grain, The manufacturing method of the lead frame of Claim 7 characterized by the above-mentioned. In the lead frame manufacturing method according to this configuration, it is possible to obtain fibers with more excellent grinding force and durability, and as a result, more excellent polishing is possible. According to such a high-hardness and fine diamond abrasive grain, the metal powder generated by polishing also becomes fine, and generation of relatively large metal pieces can be suppressed. Generation of defective products can be eliminated.

  (Additional remark 8) The said deburring process WHEREIN: The cleaning process which cleans the metal burr | flash removed from the lead frame by the said deburring means with a predetermined | prescribed cleaning means is provided. The lead frame manufacturing method according to any one of appendix 1 to appendix 8. In the lead frame manufacturing method according to this configuration, metal burrs can be efficiently removed while washing away countless metal powders adhering to the lead frame during the deburring process.

(Additional remark 9) The said cleaning means is a liquid shower, The manufacturing method of the lead frame of Additional remark 8 characterized by the above-mentioned.
(Additional remark 10) The said cleaning means is an air blow or air suction, The manufacturing method of the lead frame of Additional remark 8 characterized by the above-mentioned.

(Appendix 11) The method for manufacturing a lead frame according to any one of claims 1 to 7, or appendix 1 to appendix 10, wherein a cleaning step is provided after the deburring step.
(Additional remark 12) The said washing | cleaning process is the washing | cleaning in a washing tank, The manufacturing method of the lead frame of Additional remark 11 characterized by the above-mentioned.

(Additional remark 13) The manufacturing method of the lead frame of Additional remark 11 or Additional remark 12 characterized by providing the drying process after the said washing | cleaning process.
(Supplementary note 14) The method of manufacturing a lead frame according to any one of claims 1 to 7, or Supplementary note 1 to Supplementary note 13, further comprising a residual stress removing step after the deburring step. In the lead frame manufacturing method with this configuration, the warping of the lead frame caused by brush polishing can be eliminated.

  (Supplementary note 15) The lead frame manufacturing method according to supplementary note 14, wherein the residual stress removing step is performed by annealing. In the lead frame manufacturing method with this configuration, the distortion of the lead frame can be easily removed by the annealing process which is a known heat treatment method.

FIG. 2 is a plan view showing the entire continuous lead frame 1 in the present embodiment. FIG. 2 is a partially enlarged view showing one lead frame 1 in FIG. 1. The schematic diagram which shows a series of processes of a deburring process, a cleaning process, a washing | cleaning process, and a drying process among the manufacturing processes of a lead frame. The perspective view which shows a lead frame manufacturing apparatus, especially a deburring means. The schematic plan view of a deburring means. The perspective view of a 1st brush. The front view explaining the state in which the 1st brush rotates on a lead frame. AA sectional view of the 1st brush in Drawing 7. The front view explaining the cut end of the material at the time of a punching process. Sectional drawing of the semiconductor device after resin sealing in the II part of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lead frame, 2 ... Lead part, 11 ... Semiconductor chip, 20 ... Lead, 40 ... Manufacturing apparatus, 42 ... Deburring means, 43 ... 1st brush, 44 ... 2nd brush, 52 ... Shaft core part, 53 ... hair (flexible linear body), 53a ... tip, n ... metal burr

Claims (8)

A method of manufacturing a lead frame for use in a semiconductor device comprising a plurality of leads electrically connected to a semiconductor chip and sealed in a state where the semiconductor chip is placed on the lead,
After the punching process of forming the shape of the lead frame punching the lead frame material made of a metal plate in the press, a number of flexible linear body for driving the brush formed in a circular cylindrical flocked, the brush A deburring step for removing metal burrs generated in the lead portion formed during the punching step by rotating the brush while the brush is in sliding contact with the lead portion. Including
The flexible linear body is an aromatic polyamide fiber having heat resistance, and uniformly contains fine abrasive grains composed of diamond abrasive grains having a fineness in the range of # 1500 to # 4000. Manufacturing method. The lead frame manufacturing method according to claim 1, wherein the brush is rotated at 1500 to 3000 rpm . The lead frame manufacturing method according to claim 1, wherein the deburring unit includes a plurality of the brushes. In the deburring step, the flexible linear body planted on the brush has a tip portion in a direction opposite to the sliding direction from a direction perpendicular to the lead frame when removing metal burrs from the lead portion. 4. The lead frame manufacturing method according to claim 1, wherein the lead frame is slidably in contact with the lead portion in a posture inclined at a predetermined angle. The brush is a wheel brush in which the flexible linear body is radially planted in a radially outer direction from an axial center portion formed at the center of the brush, and the flexible linear body is 5. The lead frame manufacturing method according to claim 4, wherein the hair is planted at an angle with a predetermined angle from a radial direction of the wheel brush to a direction opposite to the rotation direction of the wheel brush. The deburring means includes a first brush that rotates in a predetermined direction and a second brush that has a rotation axis that is not parallel to the rotation axis of the first brush, and the rotation axis of the first brush; 4. The method of manufacturing a lead frame according to claim 3, wherein an angle formed by the rotation axis of the second brush is in a range of 60 degrees to 120 degrees. Above the deburring means, a liquid shower device as a means for cleaning metal burrs removed during the deburring process is disposed,
Performing a first cleaning of the pre-wash to the lead frame in the first cleaning bath as a step after the deburring step, subjected to a second washing of the main cleaning in the second washing bath, by subsequent hot air The method of manufacturing a lead frame according to claim 1, wherein the process proceeds to a drying step. A manufacturing apparatus for realizing the lead frame manufacturing method according to any one of claims 1 to 6, wherein the metal flash generated at the time of punching is removed by sliding contact with a lead portion of the lead frame. An apparatus for producing a lead frame, comprising deburring means having a brush.

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