JP2959874B2 - Lead frame manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lead frame used when assembling an electronic control unit such as a semiconductor device.

[0002]

2. Description of the Related Art A lead frame used in assembling a semiconductor device is manufactured by processing a thin metal plate by etching or stamping. This lead frame has a predetermined number of leads connected to an electronic control component such as a semiconductor element to be mounted or an external circuit, and these leads have conductivity by being formed from a thin metal plate. I have. A package of an electronic control device such as a semiconductor device is formed by mounting an electronic control component such as a semiconductor element on the lead frame and sealing it with a resin.

In a package using this lead frame, the leads and the electrodes of the electronic control parts are electrically connected by wires.
In this case, it may be necessary to partially insulate the surface of the lead. For example, recently, as a package as described above, a LOC (Lead On Chip) structure or a COL (Chip)
Unlike a conventional package structure called an “On Lead” structure, a package having a structure without an island on which a semiconductor element is mounted has been developed. As an example, FIGS. 8A and 8B show a package having a LOC structure. It will be described using FIG.

As is apparent from FIG. 1, the package 1 having the LOC structure has a semiconductor element 2 in which a tip of an inner lead 3a of a lead frame 3 and a bus bar lead 3b used for a power supply are made of an insulating film made of a polyimide film. The leads 3a and 3b are connected to the corresponding electrodes 2a of the semiconductor element 2 by a double-sided tape made of a conductive film 4 and thermosetting or thermoplastic adhesives 5 and 6 provided on both surfaces thereof. And wire 7
In this state, the semiconductor element 2 and a part of each of the leads 3 a and 3 b are sealed with a resin 8. In the package 1 having such a LOC structure, the inner leads 3a and the electrodes 2 of the semiconductor element 2 are provided.
a is connected by the wire 7 across the bus bar lead 3b. For this reason, it is necessary to prevent the short circuit between the wire 7 and the bus bar lead 3b. Therefore, as shown in FIG. 9, there is a portion A requiring insulation in a very small area on the surface of the bus bar lead 3b.

Conventionally, the following method has been adopted as a method for imparting insulation to the lead surface of a lead frame. That is, as shown in FIG.
In a conventional general multi-pin lead frame 3 'in which the tip of the inner lead 3'a is disposed around the island 3'c on which the
For the purpose of fixing the inner leads 3'a in order to prevent the deformation of the inner leads 3'a, a lead fixing tape 8 in which a thermosetting adhesive is applied to a conventional polyimide film is adhered on the inner leads 3'a. . The lead fixing tape 8 has an insulating property to prevent electrical connection with each of the inner leads 3'a. Therefore, the lead fixing tape 8 has the inner leads 3 '.
An insulating portion is formed on the surface a. As described above, the surface of the inner leads 3'a is conventionally made to have insulation by the lead fixing tape 8.

[0006]

However, in such a conventional method of imparting insulation, the punching of a film is currently limited to 2 mm square in order to ensure a predetermined accuracy. Punching of smaller films than that is practically impossible. In addition, as the film becomes smaller, the positional accuracy of the film attachment becomes worse. At present, the positional accuracy of the film attachment is limited to ± 0.3 mm. in this way,
In the conventional method of attaching the lead fixing tape 8 made of an insulating film, there is a problem of a film punching accuracy and a film attaching accuracy. It is almost impossible to have sex.

[0007] Also, punching of a film requires a special mold in accordance with the shape, which causes a problem that the manufacturing cost is high. Furthermore, the polyimide film is 70
Since it has a thickness of about 150 μm, it becomes extremely thick when attached to the inner lead, and there is also a problem that it cannot sufficiently cope with a thin package which is increasingly required in the future.

The present invention has been made in view of such a problem, and has as its object to set the position of an insulating portion formed on the surface of a lead with high accuracy, and to provide an insulating material having an insulating property without being affected by the thickness. An object of the present invention is to provide a method for manufacturing a lead frame, which can reduce the cost.

In order to solve the above-mentioned problems, a first aspect of the present invention is a semiconductor device or the like having a predetermined number of leads formed of a single metal and connected to an electronic control component such as a semiconductor element to be mounted or an external circuit. In the method of manufacturing a lead frame for assembling an electronic control device, an insulating resin film is formed on at least a part of a surface of at least one of the leads by a dispenser. According to a second aspect of the present invention, there is provided a method of manufacturing a lead frame for assembling an electronic control device such as a semiconductor device having a predetermined number of leads connected to an electronic control component such as a semiconductor element to be mounted or an external circuit. Wherein an insulating resin film is formed on at least a part of the surface of at least one of the leads by screen printing.

According to a third aspect of the present invention, there is provided an electronic control device such as a semiconductor device for assembling an electronic control device such as a semiconductor device. In a method for manufacturing a lead frame, a half-etched portion is formed on a lead by etching, a resin is applied to the half-etched portion by a dispenser, and the resin is cured to form an insulating resin film. . According to a fourth aspect of the present invention, there is provided a lead frame for assembling an electronic control device such as a semiconductor device, having a predetermined number of leads connected to an electronic control component such as a semiconductor element to be mounted or an external circuit. The manufacturing method is characterized in that a half-etched portion is formed on a lead by etching, a resin is applied to the half-etched portion by screen printing, and the resin is cured to form an insulating resin film.

According to a fifth aspect of the present invention, the resin of the insulating resin film is a UV-curable acrylic resin, and the UV-curable acrylic resin is irradiated with UV light to cure the UV-curable acrylic resin. Then, an insulating resin film is formed on the lead. The invention of claim 6 is characterized in that the resin of the insulating resin film is an epoxy resin, and the epoxy resin is heated and cured in an oven to form an insulating resin film on the lead.

The invention of claim 7 is characterized in that, after plating the leads, a resin is applied to the leads to form the insulating resin film.

According to the present invention, there is provided a lead frame for assembling an electronic control device such as a semiconductor device having a predetermined number of leads connected to an electronic control component such as a semiconductor element to be mounted or an external circuit. In the manufacturing method, after forming a half-etched portion on the lead by etching, a film is laminated on both sides of the lead frame via an etching resist film,
Form a film cut portion by notch in a portion corresponding to the half etched portion or a portion adjacent to the half etched portion, and then form a resin film in the half etched portion through the film cut portion by a chemical vapor deposition method, and then The film and the etching resist film are separated.

According to a ninth aspect of the present invention, there is provided a lead frame for assembling an electronic control device such as a semiconductor device having a predetermined number of leads connected to an electronic control component such as a semiconductor element to be mounted or an external circuit. In the manufacturing method, after forming a half-etched portion on the lead by etching, the etching resist film is peeled off, and films are laminated on both sides of the lead frame before the plating step,
In the film, a film cut portion is formed by notch in a portion corresponding to the half-etched portion or a portion adjacent to the half-etched portion, and then a resin film is formed on the half-etched portion through the film cut portion by a chemical vapor deposition method. The film is formed, and then the film is peeled off.

According to a tenth aspect of the present invention, there is provided a lead frame for assembling an electronic control device such as a semiconductor device having a predetermined number of leads connected to an electronic control component such as a semiconductor element to be mounted or an external circuit. In the manufacturing method, a half-etched portion is formed on the lead by etching and the resist film for etching is peeled off, and then a film is laminated on both sides of the lead frame after performing a plating step, and the half-etched portion of the film is formed on the half-etched portion. Form a film cut portion by notch in the corresponding portion or the portion adjacent to the half-etched portion,
Next, a resin film is formed on the half-etched portion through the film cut portion by a chemical vapor deposition method, and thereafter, the film is peeled off.

[0016]

In the method for manufacturing a lead frame according to the present invention, the insulating resin film is formed on a part of the surface of the lead, so that the insulation between the wire and the lead is ensured. In this case, the insulating resin film can be formed at a predetermined position of the lead in a minute range, with high precision, and without increasing the thickness of the lead. Especially,
Since the insulating resin film is formed in the half-etched portion formed on the lead, the thickness of the lead due to the insulating resin film hardly increases.

[0017]

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of a lead frame manufactured by an embodiment of a method for manufacturing a lead frame according to the present invention. FIG. 2 is a sectional view taken along the line II in FIG. 9, and FIG. It is a figure explaining a method. Note that the same components as those of the lead frame shown in FIGS. 8 and 9 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, a lead frame 1 manufactured by the method for manufacturing a lead frame of this embodiment
Is a portion A of the bus bar lead 3b which requires insulation.
The half-etched portion 9 is formed, and the half-etched portion 9 has an insulating resin film 1 made of a UV light curable resin such as an acrylic resin or an epoxy resin.
0 is formed. The insulating resin film 10 ensures insulation between the wires 7 that electrically connect the inner leads 3a and the electrodes 2a of the semiconductor element 2 and the bus bar leads 3b.

Next, a method of manufacturing the lead frame 1 of the present embodiment having the above-described structure will be described. FIG.
FIG. 2 is a diagram illustrating a method of manufacturing a lead frame by a dispenser method as an example of a method of manufacturing the lead frame 1. As shown in FIG.
First, a half-etched portion 9 is formed at a predetermined position on the surface of the bus bar lead 3b of the lead frame member 3d by etching. Next, as shown in FIG. 2B, a UV light-curable resin such as acrylic is injected into the half-etching section 9 from a dispenser nozzle 11 using a dispenser with an XY stage. Thereafter, the insulating resin film 10 is formed on the half-etched portion 9 by irradiating UV light to cure the UV light-curable resin.

When an epoxy resin is used as the insulating resin film 10, an epoxy resin is injected and applied to the half etching portion 9 of the bus bar lead 3b by a dispenser with an XY stage. Thereafter, the insulating resin film 10 is formed on the half-etched portion 9 by heating in an oven to cure the epoxy resin. Thus, the lead frame 1 in which the insulating resin film 10 is formed at predetermined positions of the bus bar leads 3b is manufactured.

Next, an example in which the lead frame 1 is actually manufactured by the dispenser method will be described. A lead frame member 3d is prepared by half-etching a required portion of the surface of the bus bar lead 3b, and in consideration of chemical resistance, a step of not performing a treatment of dipping in a chemical after application of the resin is adopted. The lead frame member 3d was previously subjected to a surface treatment such as Ag plating required for wire bonding, so that plating was not required after resin application.

As a resin to be applied, a UV-curable acrylic resin or a thermosetting epoxy resin is used, and both of these resins are resins containing no ionizable substances such as halides and active metals such as Na and K. Selected. Resin viscosity is adjusted for dispenser application, 2,000 to 2
As shown in Table 1, the minimum coating area is 0.4 mm width x 0.5 mm length x 0.7 mm depth, and the width and depth are the same and the length is the same. 0.6mm, 1.3m
Four types of coating ranges of m and 1.6 mm were set.

The resin was applied by using a dispenser equipped with a numerically controlled XY stage and controlling the amount of resin discharged from the dispenser nozzle 11 in accordance with the above-mentioned application range. Table 1 shows the results of the lead frame 1 thus manufactured.

[0025]

[Table 1]

As is evident from Table 1, the resin did not protrude to the side surface of the lead and did not foam in any case where the resin application range was any.

In the lead frame 1 of the present embodiment thus configured, since the half-etched portion 9 is formed by etching, the position can be determined with high accuracy and fine processing can be performed. In addition, since the nozzle 11 is positioned with high accuracy with respect to the half-etched portion 9 by the dispenser with the XY stage,
The resin is accurately injected into the half-etched portion 9, and as a result, the insulating resin film 10
It is formed at a predetermined position b in a minute range and with high precision.

Further, since the insulating resin film 10 is formed in the half-etched portion 9 where the thickness of the inner lead 3a is reduced, the thickness of the inner lead 3a is almost not increased even if the insulating resin film 10 is formed. Absent. Therefore, it is possible to reliably and sufficiently cope with a thin package. Further, since a conventional die for punching a film is not required, the manufacturing cost is reduced.

FIG. 3 shows another embodiment of the method for manufacturing a lead frame according to the present invention, and is a view for explaining a method for manufacturing a lead frame by a screen printing method. As shown in FIG. 3, in the lead frame manufacturing method of this embodiment, a resin is applied to the half-etched portion 9 of the bus bar lead 3b by screen printing using a metal mask 12, and the insulating resin film 10 is formed. Form.

As in the case of the above-described dispenser method, this screen printing method is performed using the same lead frame member 3d, the same application range (four types), and the same application resin (the viscosity is adjusted for screen printing). , The lead frame 1 was actually manufactured. In each of the manufactured lead frames 1, almost the same good results as those obtained by the above-described dispenser method were obtained.

FIG. 4 shows a lead frame 1 manufactured by another embodiment of the method for manufacturing a lead frame according to the present invention.
FIG. 2 is a sectional view similar to FIG. The same components as those of the lead frame shown in FIG. 1 are denoted by the same reference numerals, and a detailed description thereof will be omitted. As shown in FIG.
In the lead frame manufactured in this embodiment, a half-etched portion 9 is formed in a portion of the bus bar lead 3b requiring insulation as in the above-described embodiment, and the bottom surface of the half-etched portion 9 is formed. A relatively thin insulating resin film 10 is formed on the side surface. The insulating resin film 10 is made of a resin having excellent heat resistance and chemical resistance and containing little ionic impurities, such as polyparaxylylene, which is used in a chemical vapor deposition method. This insulating resin film 1
0 ensures insulation between the wire 7 and the bus bar lead 3b.

Next, a description will be given of a method of manufacturing the lead frame 1 having the above-described structure according to this embodiment by a chemical vapor deposition method (CVD method). In the method of manufacturing a lead frame by the CVD method, three patterns are set.

FIG. 5 is a view for explaining a first pattern of a method for manufacturing a lead frame by the CVD method. FIG.
As shown in (a), in the first pattern, the lead frame member 3d with the resist film 13 remaining after etching is used. The lead frame member 3d may be in a sheet shape or a frame shape. First, a half-etched portion 9 is formed at a predetermined position on the surface of the bus bar lead 3b of the lead frame member 3d by etching. After completion of the etching, a film 14 is laminated on the resist film 13 with the resist film 13 for etching attached to both surfaces of the lead frame member 3d as shown in FIG. Next, as shown in FIG. 3C, a part of a predetermined position of the film 14 is cut out by a cutter or the like to form a film cut portion 14a. In the film cutting, a portion on the half-etched portion 9 is cut according to the shape of the half-etched portion 9 as shown in FIG. 6, or a portion adjacent to the half-etched portion 9 is cut as shown in FIG. I do. In addition, the cutting method of the film 14 is as follows.
In addition to the above-described mechanical cutting method using a cutter or the like, there is also a cutting method using laser processing.

In this state, a resin film forming step is performed by the CVD method. In this step, gas penetrates into the inside of the film 14 from the film cut portion 14a, and is vapor-deposited on the half-etched portion 9, thereby forming the insulating resin film 10 on the half-etched portion 9. Thereafter, the lead frame having the insulating resin film 10 formed on the half-etched portion 9 is formed by peeling the film and the resist film and performing a plating step.

Next, the second pattern of the lead frame manufacturing method by the CVD method will be described. In the second pattern, the lead frame member 3d before plating is used after the resist film 13 is peeled off after completion of the etching. The step of the second pattern is performed in the same manner as the step of the first pattern. However, in this second pattern, only the film 14 is peeled off after the resin film is deposited.

Finally, a third pattern of the method for manufacturing a lead frame by the CVD method will be described. This third
In the pattern, after the etching is completed, the resist film 13 is peeled off, and the plated lead frame member 3d is used. The process of the third pattern is performed in substantially the same manner as the process of the first pattern. However, in the third pattern, only the film 14 is peeled off after the resin film is deposited, and the plating step after the resin film is deposited becomes unnecessary.

Next, an example in which the lead frame 1 is actually manufactured by the CVD method will be described. A lead frame member 3d having a required portion of the surface of the bus bar lead 3b half-etched is used, and the state of the lead frame member 3d before the resin film forming step by the CVD method is set. (1) The resist film 13 is removed after etching. And the surface treatment (eg, Ag plating) necessary for wire bonding has been performed in advance.
(3) After etching, resist film 1
3 was peeled off, and a material which had been subjected to a surface treatment (such as Ag plating) in advance was prepared. In the lead frame member 3d of (1), the insulating resin film 1 is formed even by a resin having poor chemical resistance.
In the lead frame member 3d of (2), since the surface is covered with the resist film 13, the masking effect of the film 14 is stabilized, and the lead frame 1 Since the masking in the state is possible, the masking efficiency is increased, and the masking efficiency is high in the lead frame member 3d of (3) for the same reason as in (2).

Then, the masked lead frame member 3d was placed in a chemical vapor deposition chamber, and a polyparaxylylene resin film was formed at room temperature under reduced pressure. The polyparaxylylene resin does not contain an ionizing substance such as a halide or an active metal such as Na or K, and has a characteristic of good chemical resistance and insulation. As the polyparaxylylene resin, Parylene N, Parylene C, Parylene D, etc., manufactured by Japan Parylene Co., Ltd. were used.

Half etching section 9 for forming resin film
As shown in Table 2, the minimum width is 0.4 mm × length 0.5 mm × depth 0.7 mm. In addition, the width and depth are the same and the length is 0.6 mm, 1.3 mm, and 1 mm. Four dimensions of .6 mm were set. Table 2 shows the results of the lead frames manufactured as described above.

[0040]

[Table 2]

As is apparent from Table 2, the resin film has a thickness of 15 μm.
m was formed to be extremely thin and uniform, but it was found that the thickness of this resin film could be controlled in μm units. In addition, the adhesion of the resin film to the metal was good, and there was no resin foaming. Also in the lead frame 1 of the present embodiment configured as described above, the leads can be partially provided with surface insulating properties in a minute range without increasing the thickness of the lead frame.

In each of the embodiments described above, the insulating resin film 10 is formed on the bus bar leads 3b. However, the present invention can also form the insulating resin film 10 on other leads. In the above-described embodiment, the present invention is described using a package having a LOC structure. However, the present invention can be applied to a lead frame used for a package having another structure.

Further, the insulating resin film 10 is provided on the half-etched portion 9 of the lead. However, in a package lead frame in which the thickness is not so problematic, the lead surface where the half-etched portion is not formed is provided. The insulating resin film 10 can also be formed on the substrate.

As is apparent from the above description, according to the lead frame manufacturing method of the present invention, an insulating resin film can be formed at a predetermined position of a lead in a minute range and with high precision. Further, even if the insulating resin film is formed, the thickness of the lead does not increase so much, so that it is possible to reliably and sufficiently cope with a thin package. Further, since a conventional die for film punching becomes unnecessary, the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along the line II in FIG. 9, showing an example of a lead frame manufactured by an embodiment of a method for manufacturing a lead frame according to the present invention.

FIG. 2 is a diagram illustrating an embodiment of a method for manufacturing the lead frame.

FIG. 3 is a diagram illustrating another embodiment of the method for manufacturing the lead frame.

FIG. 4 is a cross-sectional view taken along line II of FIG. 9 showing an example of a lead frame manufactured by another embodiment of the method for manufacturing a lead frame according to the present invention.

FIG. 5 is a diagram illustrating another embodiment of the method for manufacturing the lead frame.

FIG. 6 is a diagram illustrating an example of a film cut in the manufacturing method of this embodiment.

FIG. 7 is a view for explaining another example of the film cutting in the manufacturing method of this embodiment.

FIG. 8 shows a package having a conventional LOC structure, (a).
FIG. 8 is a perspective view showing a partially cutaway view, and FIG. 8B is a cross-sectional view taken along line VIIIB-VIIIB in FIG.

FIG. 9 is a diagram showing a portion of the bus bar lead that requires insulation.

FIG. 10 is a view showing a lead fixing tape in a conventional general lead frame.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... LOC structure package, 2 ... Semiconductor element, 3 ... Lead frame, 3a ... Inner lead, 3b ... Bus bar lead, 3d ... Lead frame member, 7 ... Wire, 8 ...
Lead fixing tape, 9 ... half-etched part, 10 ...
Insulating resin film, 11: dispenser nozzle 112: metal mask, 13: resist film, 14: film, 14
a ... Film cut section

Claims (10)

(57) [Claims] 1. A formed by a single metal, in the manufacturing method of lead frame of the electronic control unit for the assembly of a semiconductor device to have a predetermined number of leads connected to the electronic control components or external circuit such as a semiconductor element to be mounted the method of the lead frame, wherein at least one form <br/> formed to Rukoto an insulating resin film by a dispenser on at least part of the surface of the lead of the lead. 2. A semiconductor to be mounted and mounted from a single metal.
Connected to electronic control components such as body elements or external circuits
Assembly of electronic control devices such as semiconductor devices with constant leads
The method of manufacturing a lead frame of use, method of manufacturing a lead frame, wherein to Rukoto form <br/> forming an insulating resin film by screen printing on at least a portion of the surface at least one lead of the lead. 3. A semiconductor to be mounted and mounted by a single metal.
Connected to electronic control components such as body elements or external circuits
Assembly of electronic control devices such as semiconductor devices with constant leads
In manufacturing how the lead frame of use, be etched by forming a half-etching portion in the lead, together with applying a resin by a dispenser on the half-etched portion, to form an insulating resin film by curing the resin A method for manufacturing a lead frame, comprising: 4. A semiconductor to be mounted and mounted by a single metal.
Connected to electronic control components such as body elements or external circuits
Assembly of electronic control devices such as semiconductor devices with constant leads
In manufacturing how the lead frame of use by etching to form a half etching portion in the lead, together with applying a resin by screen printing to the half-etched portion, to form an insulating resin film by curing the resin A method for manufacturing a lead frame, comprising: 5. The resin of the insulating resin film is a UV-curable acrylic resin, and the UV-curable acrylic resin includes
The method for manufacturing a lead frame as claimed in any one of claims 1 to 4 by irradiating a V light to cure the UV-curable acrylic resin and forming an insulating resin layer on the lead. Wherein the resin of the insulating resin film is an epoxy resin, claims 1 and forming an insulating resin layer on the lead of the epoxy resin cured by heating in an oven 4 The method for manufacturing a lead frame according to any one of the above. 7. After plating in the lead, said Li
The insulating resin film is formed by applying resin to the substrate .
The method for manufacturing a lead frame according to any one of claims 1 to 6, wherein 8. A semiconductor formed of a single metal and mounted.
Connected to electronic control components such as body elements or external circuits
Assembly of electronic control devices such as semiconductor devices with constant leads
In manufacturing how the lead frame of use, after the formation of the half etching portion in the lead by etching, the film was laminated through an etching resist film on both surfaces of the lead frame, of the film, corresponding to the half etching part A film cut portion is formed by a notch in a portion to be formed or a portion adjacent to the half-etched portion, and then a resin film is formed in the half-etched portion through the film cut portion by a chemical vapor deposition method. A method for manufacturing a lead frame, comprising removing a resist film. 9. A semiconductor to be mounted and mounted by a single metal.
Connected to electronic control components such as body elements or external circuits
Assembly of electronic control devices such as semiconductor devices with constant leads
In manufacturing how the lead frame of use, etched by peeling off the etching resist film after forming the half etching portion in the lead, by laminating a film on both surfaces of the lead frame before plating process, of the film, the half A film cut portion is formed by notch in a portion corresponding to the etched portion or a portion adjacent to the half etched portion, and then a resin film is formed in the half etched portion through the film cut portion by a chemical vapor deposition method, and then the film is formed. And a method for manufacturing a lead frame. 10. A semiconductor formed of a simple metal and mounted.
Connected to electronic control components such as body elements or external circuits
Assembly of electronic control devices such as semiconductor devices with constant leads
In manufacturing how the lead frame of use, etched by peeling off the etching resist film to form a half etching portion in the lead, followed by laminating a film on both surfaces of the lead frame after the plating process, of the film Forming a film cut portion by notch in a portion corresponding to the half etched portion or a portion adjacent to the half etched portion, and then forming a resin film in the half etched portion through the film cut portion by a chemical vapor deposition method, Thereafter, the film is peeled off.