JPH1064959A - Film circuit and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation of suspension parts at the time of distribution and assembly in a film circuit provided with an insulating film and wiring films (leads) which electrically connect the electrodes of a semiconductor chip and the other electronic parts on at least one major face. SOLUTION: When a reinforcing ring 8 surrounding a semiconductor chip which are electrically connected with the respective wiring films 3 at the electrodes is integrally provided through the suspension parts 10, reinforcing parts 17 for reinforcing the suspension parts 10 are provided on the suspension parts 10. The film circuit 1 is formed by forming the ring instead of an outer lead by applying a lead frame forming technology for forming an inner lead on one side and forming the outer lead by a surface layer on the other side with a laminated board of more than three layers as a base.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises an insulating film and a plurality of wiring films formed on at least one main surface for electrically connecting an electrode of a semiconductor element to another electronic component. The present invention relates to a film circuit and a manufacturing method thereof.

[0002]

2. Description of the Related Art As a semiconductor device, a lead connected to its electrode at one end is formed on one side of an insulating film and an external terminal connected to the other end of the lead is formed on a semiconductor element. There is one in which a film circuit formed on the other surface side of the insulating film is mounted, and a reinforcing outer ring surrounding the semiconductor circuit is formed outside the semiconductor element.

However, in such a semiconductor device, an outer ring surrounding the semiconductor element is arranged, and the outer ring and the semiconductor element are aligned with each other and a sealing agent is filled therebetween. Is indispensable, and the necessity of a step of aligning the positions is a factor that hinders a reduction in the number of assembling steps of the semiconductor device. This naturally becomes a factor that hinders the cost reduction of the semiconductor device.

Therefore, a semiconductor device which solves such a problem has been proposed. FIGS. 7A and 7B show an example of such a semiconductor device, wherein FIG. 7A is a plan view and FIG.
It is an BB sectional view taken on the line of FIG.

In the drawings, reference numeral 1 denotes a film circuit, and 2 denotes an insulating film, which forms the base of the film circuit 1. 3,
Reference numerals 3,... Denote leads (wiring films) formed on one side (lower side) of the insulating film 2, and the tips 3a are connected to the electrode pads (5) of the semiconductor element (4). . The leads 3, 3,... Are formed by forming a metal such as copper or nickel using a resist having a negative pattern for the pattern to be formed as a mask.

The leads 6, 3,... Are the respective leads 3, 3,.
Ball-shaped external terminals formed on the ends 3b, 3b,... Opposite to the side connected to the electrode pads (5) of the semiconductor element (4). The base (insulating film) 2 is formed on the surface on the side opposite to the semiconductor element, and is connected to the end 3 b of the lead 3 through a hole in the base 2.

Reference numeral 8 denotes a reinforcing outer ring surrounding the semiconductor element (4), which is integrally formed outside the main part of the film circuit through hanging portions 10, 10, 10, and 10, for example, copper, aluminum, It has a laminated structure made of copper, nickel or the like. On the other hand, the suspension portions 10, 10, 10, 10 are formed of the same layer as the leads 3, 3,... And are therefore made of, for example, copper or nickel.

According to such a film circuit, FIG.
As shown in FIG. 7A, since the outer ring 8 is integrally formed on the outer portion of the film circuit main portion 15 via the hanging portions 10, 10, 10, 10, as shown in FIG. Then, the ring 8 is positioned with respect to the semiconductor element 4 simply by placing the film circuit 1 on the semiconductor element 4.
Therefore, there is no need to provide a special step only for providing the ring 8 in a predetermined positional relationship with the semiconductor element 4.

Therefore, it is possible to reduce the number of assembling steps of the semiconductor device, and to reduce the manufacturing cost of the semiconductor device.

[0010]

By the way, in the conventional film circuit, the width of the hanging portion is small, for example, 18 to
Since the thickness is about 25 μm, the mechanical strength is inferior, so that there is a problem that deformation is liable to occur only by applying a small impact at the time of delivery or assembly.

If the hanging portion of the film circuit is easily deformed as described above, in the worst case, the hanging portion is cut and the circuit portion falls off, so that the yield is reduced. Further, if the hanging portion of the film circuit is easily deformed, the positional accuracy between the circuit portion and the outer ring is reduced, so that the assembly is hindered.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a novel film circuit capable of preventing deformation of a hanging portion only by improving the structure of the hanging portion, and a method of manufacturing the same. The purpose is to provide.

[0013]

According to a first aspect of the present invention, there is provided a film circuit, wherein a reinforcement for reinforcing the suspension is provided on a suspension supporting a ring surrounding the semiconductor element.

Therefore, according to the film circuit of the first aspect, since the reinforcing portion is provided on the suspending portion, the suspending portion is strengthened, so that the suspending portion can be prevented from being deformed.

Therefore, the hanging portion is not broken and the circuit portion does not fall off, and the positional accuracy between the circuit portion and the outer ring is improved, so that there is no trouble in assembling.

According to a third aspect of the present invention, there is provided a method of manufacturing a film circuit according to the first aspect of the present invention, wherein three or more laminated boards are provided on one surface side of the laminated board by itself or on the surface layer. The wiring film and the hanging portion are formed by another formed metal layer, an insulating film is formed, and external terminals are formed so as to be connected to the other end of the wiring film. Forming a ring, and forming a ring composed of the layer by selective etching of the laminated plate through the layer and selective etching of a layer on the other surface side of the laminated plate.

Therefore, according to the manufacturing method of the third aspect, a lead frame is formed by forming an inner lead on one side and forming an outer lead by the surface layer on the other side, based on a laminate having three or more layers. Applying technology to form a ring in place of the outer lead and forming a reinforced part simultaneously with the external terminal, it is possible to obtain a film circuit with a ring, and it is easy to use the already developed lead frame manufacturing technology as it is The film circuit according to claim 1 or 2 can be obtained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIGS. 1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is a plan view, and FIG.
It is an BB sectional view taken on the line of FIG.

In the drawings, reference numeral 1 denotes a film circuit, and 2 denotes an insulating film, which forms the base of the film circuit 1. 3,
Reference numerals 3,... Denote leads (wiring films) formed on one side (lower side) of the insulating film 2, and the tips 3a thereof are connected to the electrode pads (5) of the semiconductor element (4). become. The leads 3, 3,... Are formed by forming a metal such as copper or nickel using a resist having a negative pattern for the pattern to be formed as a mask.

.. Represent the leads 3, 3,.
Ball-shaped external terminals formed on the ends 3b, 3b,... Opposite to the side connected to the electrode pads (5) of the semiconductor element (4). The base (insulating film) 2 is formed on the surface on the side opposite to the semiconductor element, and is connected to the end 3 b of the lead 3 through a hole in the base 2.

Reference numeral 8 denotes a reinforcing outer ring surrounding the semiconductor element (4), which is integrally formed on the outside of the main part of the film circuit through suspending portions 10, 10, 10, and 10, for example, copper, aluminum, It has a laminated structure made of copper, nickel or the like. On the other hand, the suspension portions 10, 10, 10, 10 are formed of the same layer as the leads 3, 3,... And are therefore made of, for example, copper or nickel. In addition, the hanging parts 10, 10,
10 and 10 are provided wider than the conventional example. This is to form a reinforced portion thereon as described later.

Reference numeral 17 denotes a reinforcing portion provided on the suspension portions 10, 10, 10, and is made of the same material as the ball-shaped external terminals 6, 6, for example, nickel, solder, or gold. The reinforcing portion 17 includes the hanging portions 10, 10, and 10.
, And external terminals 6, 6,.
.. formed simultaneously with the formation of

This film circuit, as shown in FIG.
On the outer part of the film circuit main part 15, a reinforcing part 1
2, the film circuit 1 is simply placed on the semiconductor element 4 so that the film circuit 1 is mounted on the semiconductor element 4, as shown in FIG. When positioning the ring 8 with respect to the semiconductor element 4,
The external ring 8 is positioned with respect to the semiconductor element 4 without deforming the hanging parts 10, 10, 10.

Therefore, the hanging portion is not cut and the circuit portion does not fall off, and the positional accuracy between the circuit portion and the outer ring is improved, so that there is no trouble in assembling.

FIG. 2 is a sectional view showing a semiconductor device in which the film circuit shown in FIG. 1 is assembled to a semiconductor element.
In the figure, 4 is a semiconductor element, 5 is its electrode pad,
Reference numeral 7 denotes a buffer made of, for example, silicon grease, which is interposed between the film circuit 1 and the semiconductor element 4. Reference numeral 9 denotes a sealant for sealing and fixing between the outer ring 8 and the semiconductor element 4 and between the outer ring 8 and the film circuit 1.

Next, a method of manufacturing the film circuit 1 according to the present invention will be described in the order of steps with reference to FIGS. This manufacturing method is a lead frame manufacturing technique for forming an outer lead on one side and an inner lead on the other side based on a metal laminate having a three-layer structure.
The technology introduced in JP-A-2111834 and JP-A-7-147364 uses this lead frame manufacturing technology. ), The leads 3, 3,... And the suspension portions 10, 10, 10, 10 of the film circuit 1 are formed instead of the inner leads, and the outer ring 8 is formed instead of the outer leads. It is a big feature.

(A) First, as shown in FIG. 3A, a metal laminated plate 11 having a three-layer structure is prepared. The laminated board 11
A copper layer 12 having a thickness of, for example, 150 μm serving as the ring 8 and a thickness of, for example, 3 μm serving as an etching stopper
And a plating base layer 14 made of copper or nickel having a thickness of, for example, 2 μm.

(B) Next, as shown in FIG. 3B, leads 3, 3,... And suspensions 10, 10, 10, 10 are formed on the plating underlayer 14. The lead 3,
3, ... and the hanging parts 10, 10, 10, 10 are coated with a resist of a negative pattern for the pattern to be formed, and the resist is used as a mask and the layer 14 is used as a base and copper (or nickel) is used. It can be formed by plating (plating thickness, for example, 30 μm).

(C) Next, as shown in FIG. 3 (C), a plurality of film circuits are integrally connected by selectively performing etching through both sides of the metal laminate 11 from the both sides. Form into a lead frame shape.

(D) Next, as shown in FIG. 3D, an insulating film 2 is formed on the surface of the laminate 11 on the lead forming surface side.
Are formed selectively.

(E) Next, as shown in FIG. 3E, solder balls 6, 6,... Serving as external terminals are formed on the surfaces of the leads 3, 3,... Using the insulating film 2 as a mask.・
To form At the same time, the hanging parts 10, 10, 10,
A reinforcing portion 17 for reinforcing the hanging portions 10, 10, 10, 10 is formed on 10. The solder balls 6, 6,... And the reinforcing portions 17 are nickel-plated (thickness, for example, 80 μm).
And by soldering or gold plating (thickness, for example, 30 μm).

(F) Next, as shown in FIG. 3 (F), the inside of the portion 8 serving as the outer ring of the thick copper layer 12 located on the back side of the laminated board 11 is selectively etched from the back side. To remove. At this time, the aluminum layer 13 serves as an etching stopper. At this stage, the aluminum layer 13 remains except for the portion removed during the selective etching shown in FIG.

(G) Next, as shown in FIG. 3 (G), the leads 3, 3,...
10 (However, no hanging portion 10 appears in FIG. 3)
Is used as a mask to etch the underlying plating layer 14 and the aluminum layer 13 serving as an etching stopper. As a result, the leads 3, 3,... And the suspension portions 10, 10, 10, 10 are independent, and are not in a state of being electrically short-circuited with each other for the first time. Reference numeral 15 denotes a main part of the film circuit 1. The main part 15 can be seen as being separated from the outer ring 8 in FIG. 3 (G). , 10,
This is because 10 does not appear.
It is integrally connected to the outer ring 8 via 10, 10, 10.

(H) Next, if necessary, as shown in FIG. 3 (H), the ends 3a, 3a,
, Are formed with bumps 16, 16,. In the case of the film circuit 1 shown in FIG. 1, this step is not necessary because there are no bumps. However, in the later-described modified example shown in FIG. 5, there is a bump. In this step, bumps are formed. Incidentally, the bump may be formed on the semiconductor element 4 side in some cases.

According to such a method, the method of manufacturing a lead frame in which outer leads are formed on one side and inner leads are formed on the other side based on a three-layer laminated metal plate as a base. The film circuit according to the present invention can be manufactured. In this embodiment, the leads are formed by growing the plating film using the resist film selectively formed on the plating base film as a mask, but the layer 14 made of copper or nickel is formed thicker. The leads may be formed by patterning the leads by selective etching.

FIGS. 4A to 4D show the steps of assembling the film circuit 1 to the semiconductor device.

(A) First, as shown in FIG. 4A, the lead frame-shaped film circuit 1 is positioned on the aligned semiconductor elements 4 with the buffer 7 interposed therebetween. (B) Next, as shown in FIG.
Are connected to the semiconductor element 4
Are connected, for example, by single point bonding.

(C) Next, as shown in FIG. 4C, a sealing agent 9 such as epoxy resin or silicon resin is injected between the semiconductor element 4 and the film circuit 1 / outer ring 8 by potting to seal. And fixing between the semiconductor element 4 and the film circuit 1 / outer ring 8.

(D) Next, as shown in FIG. 4D, the film circuit 1 is separated from the others by cutting unnecessary portions of the lead frame in which the plurality of film circuits 1 are integrally connected. Thereby, the film circuit 1 is provided as an intermediate circuit board, and the ball grid array-shaped external terminals 6 connected to the respective electrodes of the semiconductor element 1 are provided on the intermediate circuit board.
, And the reinforcing portion 17, and a semiconductor device reinforced by the outer ring 8 can be obtained.

According to such an assembling method, the hanging portion 1 on which the reinforcing portion 17 is provided on the film circuit 1 is provided.
Since the outer ring 8 is formed integrally with the semiconductor device 4 via the holes 0, 10, and 10, the outer ring 8 is naturally positioned with respect to the semiconductor element 4 when the film circuit 1 is positioned with respect to the semiconductor element 4. , 10 and 10 are not deformed.

FIG. 5 is a cross-sectional view showing a modification of the film circuit shown in FIG. 1. The difference between this modification and the circuit shown in FIG. The only difference is that it is bonded to the electrode pad 5 via the metal bump 16 formed on the substrate.

FIG. 6 is a plan view showing another modification of the film circuit shown in FIG.

The difference between the film circuit 1 of this modification and the film circuit 1 shown in FIG.
10 and 10, and the hanging portions 10, 10, and 10 are formed not in a linear shape but in a rectangular shape, and the reinforcing portion 1 having a large area is provided.
No. 7 is formed to obtain greater strength, and there is no difference in other points.

In the above embodiment, the suspension 1
Although 0 is provided at the four corners of the film circuit 1, it is not necessarily limited thereto. For example, it may be provided at an intermediate portion of each piece.

[0046]

According to the film circuit of the first aspect, since the reinforcing portion is provided on the suspension portion, the suspension portion is strengthened, so that the suspension portion is prevented from being deformed.

Accordingly, the hanging portion is not cut and the circuit portion does not fall off, and the positional accuracy between the circuit portion and the outer ring is improved, so that there is no trouble in assembling.

According to a third aspect of the present invention, there is provided a lead frame forming technique of forming an inner lead on one side and forming an outer lead by a surface layer on the other side based on a laminate having three or more layers. By applying a ring instead of the outer lead and forming a reinforced part simultaneously with the external terminal, a film circuit with a ring can be obtained, and it is easy to request using the already developed lead frame manufacturing technology as it is The film circuit according to item 1 or 2 can be obtained.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment of a film circuit of the present invention, wherein FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line AA of FIG. It is.

FIG. 2 is a sectional view showing a semiconductor device in which the film circuit shown in FIG. 1 is assembled to a semiconductor element.

FIGS. 3A to 3H are cross-sectional views showing an example of a method for manufacturing a film circuit of the present invention in the order of steps.

4A to 4D are cross-sectional views illustrating an example of a method of assembling the film circuit of the present invention to a semiconductor element in the order of steps.

FIG. 5 is a sectional view showing a modification of the film circuit shown in FIG.

FIG. 6 is a plan view showing another modified example of the film circuit shown in FIG. 1;

7A and 7B show a conventional example, in which FIG. 7A is a plan view and FIG.
FIG. 3 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

1 ... film circuit, 2 ... insulating film, 3 ...
..Leads (wiring films), 4 ... semiconductor elements, 5 ...
Electrode (pad), 6 ... external terminal, 8 ... ring,
10 ... hanging part, 11 ... laminated board, 17 ... reinforcement part.

Claims (3)

[Claims] 1. An insulating film comprising: an insulating film; and a plurality of wiring films formed on at least one main surface of the insulating film for electrically connecting an electrode of the semiconductor element and another electronic component, and surrounding the semiconductor element. A film circuit in which a ring is provided integrally via a hanging portion, wherein a reinforcing portion for reinforcing the hanging portion is provided on the hanging portion. 2. The film circuit according to claim 1, wherein the reinforcing portion is made of the same material as an external terminal connected to the other end of the wiring film. 3. A laminate having three or more layers, a wiring film and a suspending portion formed on one surface side by the surface layer itself or another metal layer formed on the surface layer, and an insulating film. Forming an external terminal so as to be connected to the other end of the wiring film, simultaneously forming a reinforced portion on the suspension portion, selectively etching the laminated plate through the same, 3. The method according to claim 1, wherein a ring made of the layer is formed by selective etching of a layer on the other surface side of the plate.