JP3082568B2 - Method and apparatus for attaching film to adherend such as lead frame - 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 and an apparatus for attaching a film to a material to be adhered such as a lead frame, and more particularly to an adhesive film for preventing a step or a shift at the tip of a lead frame, mainly a type which is attached at a high temperature. The present invention relates to a method and an apparatus for affixing a film to a material to be bonded such as a lead frame for the above film.

[0002]

2. Description of the Related Art In a lead frame on which an IC or an LSI is mounted, an insulating film processed into a strip shape by punching or cutting in order to prevent a step or a shift of a tip portion from the past is conventionally attached to the lead tip portion. Much has been done. This insulating film is formed by applying an adhesive to both surfaces of a polyimide film.

A conventional semiconductor device using such an insulating film will be described with reference to FIGS. 5, 6 and 7. FIG. FIG. 5 is a cross-sectional view of a conventional semiconductor device, in which a silicon chip 10 is fixed by an insulating film 13 bonded to a power supply bus bar 11 and an inner lead 12, and the bus bar 11 and the inner lead 12 are further bonded by a chip. The silicon chip 10 and the bonding wires 15 are electrically connected to each other at a wire bonding portion 14 formed on the opposite surface.

FIG. 6 shows a bus bar 11 and an inner lead 1.
2 is shown, and FIG. 7 is a cross-sectional view taken along the line AA. The thickness a (about 5 μm) is applied to the wire bonding portion 14 formed at a predetermined position of the tip of the bus bar 11 and the inner lead 12.
m) Au or Ag partial plating is applied.

Conventionally, a film sticking apparatus as shown in FIG. 8 has been used to stick the above-mentioned insulating film to a lead frame.

This film sticking apparatus has a cylinder 17 for lowering the punch 16 in the direction of the arrow, a punch guide 18 for guiding the punch 16, a die 19 on which the insulating film 13 is mounted, and a lead frame 20 having an upper surface. The insulating film 13 is punched into a predetermined shape by the lowering of the punching punch 16, and the punched insulating film 13 is sandwiched by the heat plate 21 together with the lead frame 20 therebelow. At a predetermined position by thermocompression bonding.

[0007]

However, according to the conventional film bonding apparatus, when the insulating film is pressed against the bonding surface of the lead frame, as shown in FIG. 9, wire bonding on the surface opposite to the bonding surface of the insulating film 13 is performed. Part 14
In this case, there is a problem that a step a is generated between the other portion and the other portion, so that pressure is not applied uniformly and an unbonded portion is generated. Accordingly, an object of the present invention is to provide a method and an apparatus for attaching a film to a material to be adhered such as a lead frame, which can absorb a step on the surface of a lead frame and uniformly apply pressure to an insulating film attaching surface. .

[0008]

SUMMARY OF THE INVENTION The present invention heats a metal adherend such as a lead frame in order to absorb a step on the surface of the lead frame and to apply a uniform pressure to the insulating film attachment surface. Then, the adhesive insulating film is processed into a predetermined shape by cutting or punching,
A lead frame for supporting a heated material to be bonded on a flat metal member having a lower hardness than the material to be bonded, and pressing and bonding an adhesive insulating film processed on the material to be bonded supported on the flat member. And a method for attaching a film to a material to be bonded.

Further, according to the present invention, in order to absorb a step on the surface of the lead frame and to apply a uniform pressure to the surface to which the insulating film is attached, the supporting means for mounting the material to be bonded is provided with a pressing means on its surface. By the pressing by the irregularities of the shape according to the step of the surface of the adhered material is formed ,
A structure having a step absorbing means made of a metal softer than the hardness of the material to be bonded , or a structure which is inserted between the supporting means and the material to be bonded and which has a step on the surface of the material to be bonded by pressing by pressing means. Provided is an apparatus for attaching a film to a material to be bonded, such as a lead frame, having a structure having unevenness portions formed in accordance with the shape and having a step absorbing means made of a metal softer than the hardness of the material to be bonded.

[0010]

According to the method and apparatus for attaching a film to a material to be bonded such as a lead frame according to the present invention, when pressing an adhesive insulating film against a heated material to be bonded, a metal having a hardness lower than that of the material to be bonded is used. The formed flat member is plastically deformed based on the step on the surface of the material to be bonded and absorbs the step. This prevents the film pressing surface of the adherend from being distorted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a film sticking apparatus according to the present invention will be described in detail with reference to the drawings. Portions having the same configuration and function as those of the prior art are denoted by the same reference numerals, and duplicate description will be omitted.

FIG. 1 shows a cross-sectional shape of a heat plate 1 used in the film sticking apparatus of the present invention. An aluminum plate 2 is bonded to the surface of the heat plate 1 on which a lead frame (not shown) is mounted. ing. The aluminum plate 2 used had a thickness of 0.05 to 10 mm.

Using the heat plate 1 described above, FIG.
The method for attaching a film using the film attaching apparatus described in (1) will be described below. First, the lead frame 20 is mounted on the heat plate 1 on which the aluminum plate 2 is adhered to the surface, and the insulating film 13 punched by the lowering of the punch 16 is sandwiched between the heat plate 1 and the lead frame 20 thereunder to apply pressure. In addition, close contact. At this time, the aluminum plate 2 bonded to the surface of the heat plate 1 is plastically deformed according to the unevenness due to the partial plating applied to the surface of the lead frame 20.

FIG. 2 shows the aluminum plate 2 on the heat plate 1 pressed by the lead frame 20,
FIG. 3 is a sectional view taken along the line AA in FIG. On the aluminum plate 2 bonded to the surface of the heat plate 1, there is formed a transfer pattern 2A that is plastically deformed in accordance with unevenness due to partial plating applied to the surface of the lead frame 20 when the insulating film 13 (not shown) is bonded. You.

When the heat plate 1 having the aluminum plate 2 on which the transfer pattern 2A was formed was repeatedly used for film bonding, pressure was uniformly applied to the entire film mounting surface of the lead frame 20, and partial plating was performed. It was confirmed that the insulating film 13 could be stuck without generating an unbonded portion regardless of the presence or absence.

Furthermore, according to the present invention, since an aluminum plate is stuck to the surface of the heat plate, the adhesion of Au or Ag particles constituting the partial plating is hardly observed, so that the lead is attached when the insulating film is stuck to the lead frame. The dents on the frame can be eliminated, contributing to improved quality.

FIG. 4 shows that instead of attaching the aluminum plate 2 to the surface of the heat plate 1, a strip-shaped aluminum strip 3 having a thickness of 0.1 mm is continuously inserted into the upper portion of the heat plate 1 and the insulating film 13 is punched out. Also, a punching press 16 pressed against the lead frame 20 and a film sticking device sandwiched between the aluminum strip 3 and the heat plate 1 are shown.

The aluminum strip 3 located on the upper portion of the heat plate 1 is continuously supplied in the direction of the arrow shown in FIG. 1 by the rotation of a take-up reel 4 and a take-up reel 5 provided near the film sticking device.

When the insulating film 13 is repeatedly applied and pressed against the lead frame 20, the aluminum strip 3 gradually deforms the concavo-convex shape of the transfer pattern 2A. If the degree of deformation exceeds the allowed dimensions,
By rotating the feed reel 4 and the take-up reel 5 to move the aluminum strip 3 by a fixed length, the aluminum strip 3 having a new surface is placed on the heat plate 1.

As described above, by continuously supplying the aluminum strips 3, the aluminum strips 3 can be easily replaced even if the transfer pattern 2A is deformed, and the bonding of the insulating film 13 to the lead frame 20 is achieved. Defects can be prevented.

In the present invention, a strip made of aluminum is used. However, the strip supplied on the heat plate 1 is not limited to aluminum, and has a hardness and a hardness at which irregularities on the surface of the lead frame 20 can be easily transferred. A strip made of another material may be used as long as the material has strength.

[0022]

As described in the foregoing, according to the film joining method of the adherend such as a lead frame of the present invention, by heating the adhesive material of metals such as lead frames, absolute adhesion
The edge film is processed into a predetermined shape by cutting or punching, and the heated material to be bonded is supported on a metal flat member having a lower hardness than the material to be bonded, and is processed into the bonded material supported on the flat member. Since the applied adhesive insulating film is pressed and bonded, the step on the surface of the lead frame can be absorbed and the pressure can be continuously and uniformly applied to the insulating film attachment surface.

According to the apparatus for attaching a film to a material to be bonded, such as a lead frame, of the present invention, the supporting means for mounting the material to be bonded is pressed against the surface thereof by a pressing means in accordance with a step on the surface of the material to be bonded. Is formed of a metal that is softer than the hardness of the material to be bonded.
Structure with a level difference absorbing means that, or is inserted between the support means and the adhesive, uneven portion having a shape corresponding to the level difference of the surface of the adhesive material is formed by the pressing by the pressing means,
Since the structure has a step absorbing means made of a metal softer than the hardness of the material to be bonded, the step on the surface of the lead frame can be absorbed and pressure can be continuously and uniformly applied to the insulating film attachment surface.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heat plate used in the film sticking apparatus of the present invention.

FIG. 2 is an explanatory view showing a film sticking step by the film sticking apparatus of the present invention.

FIG. 3 is an explanatory view showing a film sticking step by the film sticking apparatus of the present invention.

FIG. 4 is an explanatory view showing a modified example of the film sticking apparatus of the present invention.

FIG. 5 is an explanatory diagram of a semiconductor device using an insulating film.

FIG. 6 is an explanatory diagram showing the arrangement of inner leads and bus bars.

FIG. 7 is a sectional view taken along the line AA of FIG. 6;

FIG. 8 is an explanatory view showing a conventional film sticking apparatus.

FIG. 9 is an explanatory view showing an attaching step by a conventional film attaching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat plate 2 Aluminum plate 3 Aluminum strip 4 Sending reel 5 Take-up reel 10 Silicon chip 11 Bus bar 12 Inner lead 13 Insulating film 14 Wire bonding part 15 Bonding wire 16 Punching punch 17 Cylinder 18 Punch guide 19 Die 20 Lead frame 21 Heat plate

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ryuji Yonemoto 3550 Kida Yomachi, Tsuchiura-shi, Ibaraki Hitachi Systems, Ltd. System Materials Research Laboratories (72) Inventor Toshio Kawamura 3-1-1 Sukekawacho, Hitachi-shi, Ibaraki No. 1 Nippon Electric Cable Co., Ltd. Wire plant (56) References JP-A-5-299565 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 23/50

Claims (6)

(57) [Claims] 1. An adhesive insulating film is heated by heating a metal adherend such as a lead frame by cutting or punching into a predetermined shape, and the heated adherend is harder than the adherend. Bonding on an adhesive insulating film processed on the material to be bonded supported on the flat member by pressing on the metal flat member having a small size, and bonding the lead frame or the like. How to attach film to materials. 2. The method according to claim 1, wherein the heating of the material to be bonded is performed on the flat member. 3. An adhesive insulating film processed by cutting or punching according to the shape of a metal material to be bonded such as a lead frame, on a supporting means provided with heating means for heating the material to be bonded. In a film sticking apparatus having a pressing means for pressing and bonding to the material to be bonded heated to a predetermined temperature, the supporting means for mounting the material to be bonded is bonded to the surface thereof by pressing by the pressing means. An uneven portion having a shape corresponding to the step of the surface of the material is formed ,
An apparatus for affixing a film to a material to be bonded such as a lead frame , comprising a step absorbing means made of a metal softer than the metal . 4. The film sticking apparatus according to claim 3, wherein the step absorbing means has a structure formed of a material softer than the hardness of the material to be bonded. 5. An adhesive insulating film processed by cutting or punching according to the shape of a metal material to be bonded, such as a lead frame, on a supporting means having a heating means for heating the material to be bonded. In a film sticking apparatus having a pressing means for pressing and bonding to the material to be bonded heated to a predetermined temperature, the film bonding apparatus is inserted between the supporting means and the material to be bonded, and the bonding is performed by pressing by the pressing means. An uneven portion having a shape corresponding to a step on the surface of the material is formed, and a step absorbing means made of a metal softer than the hardness of the material to be bonded is provided. Film pasting equipment. 6. A structure according to claim 5, wherein said step absorbing means is a belt-like body continuously inserted by intermittent movement between said support means and said material to be bonded. Film sticking device for adhesives.