JPH06333998A - Manufacture of tab tape and manufacture of lead frame - Google Patents

Abstract

PURPOSE:To provide the manufacture of a TAB tape, which can mold conductor patterns having enough strength and at narrow pitches by etching method. CONSTITUTION:When manufacturing a TAB tape, where a conductor pattern with a specified thickness is made on the film 12 consisting of polyimide, a protective resist layer 16 in specified pattern is formed on a copper foil 10 thinner than the conductor pattern made on one side of a film 10, and then a copper foil 10 is etched to form a conductor pattern body 18 in specified shape. Next, a plated metallic layer 20 is made by electrolytic plating on the periphery of the conductor pattern body 18 being exposed by exfoliating the protective layer 16, thus this is made into a conductor pattern with a specified thickness.

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 TAB tape and a method for manufacturing a lead frame, and more specifically, a TA having a conductor pattern formed on a flexible resin film.
The present invention relates to a method for manufacturing a B tape and a method for manufacturing a lead frame obtained by etching a thin metal plate.

[0002]

2. Description of the Related Art With the progress of high integration and miniaturization of semiconductor chips, the lead frame 200 shown in FIG. 7 on which the semiconductor chips are mounted is also required to have a large number of pins, and the inner leads 202, 202 ... The miniaturization of is also required. In a lead frame that can meet the demand for such a large number of pins, the inner lead pitch interval becomes fine, and molding by press working becomes difficult.
It is formed by etching. The steps of such etching process are shown in FIG. In FIG. 10, first, a metal thin plate 400 made of a metal such as copper and having a thickness substantially equal to the thickness of inner leads to be formed is used.
00 on both sides of the protective resist layers 402, 4 having a desired pattern.
02 ... Is formed [FIG. 10 (a)]. Next, the metal thin plate 4 on which the protective resist layers 402, 402 ... Are formed.
00 is immersed in an etching solution, and etching is performed from both sides of the metal thin plate 400. On both surfaces of the metal thin plate 400 dipped in the etching solution, the exposed portions without being covered with the protective resist layer 402 are selectively etched. Etching portion 404 etched in this way,
404 gradually advances to the inside of the thin metal plate 400 [Fig. 10 (b)]. When the etching progresses and the etching portions 404 are connected to each other, the inner lead 4
., 406 ... Are formed.

In order to easily connect the fine inner leads of the lead frame thus obtained and the mounted semiconductor chip, a TAB (Tape Automate) shown in FIG.
d Bonding) tape is being used. TA shown in FIG.
In the B tape 100, conductor patterns 104, 104, ... Made of metal such as copper metal are formed on a flexible resin film 102 formed of resin such as polyimide. The conductor pattern 10 is formed on the resin film 102.
4 and the device hole 10 in which the tip of the conductor pattern 104 projects.
8 are provided.

The TAB tape 100 is also formed by etching, and the processing steps are shown in FIG. First, the conductor patterns 104, 10 to be formed are formed on one surface of a flexible resin film 302 made of a resin such as polyimide.
4, a metal foil 300 having a thickness substantially equal to that of No. 4 is attached by an adhesive layer 304, and then a protective resist layer 30 having a desired pattern is formed.
.. are formed on the metal foil 300. Then
The resin film 302 having the protective resist layers 306, 306, ... Formed thereon is dipped in an etching solution to perform etching from one side of the metal foil 300. In the resin film 302 dipped in the etching solution, the protective resist layer 306
The portion of the metal foil 300 that is exposed without being covered with the metal is selectively etched. The etching portions 308, 308, ... Etched in this way gradually become the metal foil 30.
It proceeds to the inside of 0 [Fig. 8 (b)]. As the etching progresses, the bottom of the etched portion 308 is moved to the adhesive layer 304.
., And the conductor patterns 310, 310 ... Of a predetermined width are formed, the etching is completed.

[0005]

According to the etching process shown in FIG. 8 or FIG. 10, it is possible to form a TAB tape or a lead frame having a fine pattern which can meet the demands for increasing the number of pins. By the way, with the recent progress in high integration and miniaturization of semiconductor chips, further fine patterning of TAB tapes and lead frames is required. However, in the conventional TAB tape formed by the etching process, as shown in FIG. 9, the cross-sectional shape of the formed conductor pattern 310 is such that the upper side is the resin film 3
It has a substantially trapezoidal shape that is shorter than the lower side attached to 02. For this reason, the tip surface of the conductor pattern 310, which is the bonding surface with the terminals of the semiconductor chip, etc., also becomes narrow, and the bondability tends to deteriorate. Furthermore, in order to ensure the insulation between the conductor patterns 310, it is necessary to set the shortest distance w between the conductor patterns 310 to a predetermined distance or more. Therefore, the pitch p between the conductor patterns 310 is determined by the shortest distance w. For these reasons, it is difficult to further reduce the pitch of the conductor pattern 310 of the TAB tape by the conventional method of manufacturing the TAB tape. On the other hand, the conductor pattern 310 formed by reducing the thickness of the metal foil 300.
Although it is possible to make the cross-sectional shape of the TAB tape close to a rectangle, the strength of the conductor pattern 310 becomes insufficient and the conductor pattern 310 is easily deformed, which makes it difficult to handle the TAB tape.

Further, in the lead frame formed by etching, projections 408, 408, ... Are formed on the side surfaces of the inner lead 406, as shown in FIG. Therefore, in order to ensure the insulation between the inner leads 406, it is necessary to keep the shortest distance W between the inner leads 406 to a predetermined distance or more.
The pitch P between is determined by the shortest distance W. Furthermore,
Since the protruding portion 408 becomes larger as the plate thickness T of the metal thin plate 400 to be etched becomes thicker, it becomes difficult to form the inner lead having a narrow pitch if the inner lead having sufficient strength is not formed. On the other hand, by thinning the metal thin plate 400, the cross-sectional shape of the inner lead 406 to be formed can be approximated to a rectangle, but the strength of the inner lead 406 is insufficient and the inner lead 406 is easily deformed. It will be difficult. As described above, in the conventional method of manufacturing a TAB tape and a lead frame by etching, it was not possible to obtain a TAB tape or a lead frame having a sufficient strength and having a narrow pitch conductor pattern or inner leads. Therefore, an object of the present invention is to provide a method of manufacturing a TAB tape and a method of manufacturing a lead frame, which has a sufficient strength and can form a conductor pattern or inner leads having a narrow pitch by an etching method.

[0007]

The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, formed a fine conductor pattern body or inner lead body on a thin metal foil or thin metal plate by etching. After that, a plated metal layer is formed on the conductor pattern body or the inner lead body by electrolytic plating to form a conductor pattern or an inner lead having a predetermined thickness, so that a conductor pattern or an inner conductor with a narrow pitch can be provided with sufficient strength. The inventors have found that leads can be formed and have reached the present invention. That is, the present invention provides a TAB in which a conductor pattern is formed on a flexible resin film.
When manufacturing a tape, on one surface of the resin film, after forming a metal layer thinner than the thickness of the conductor pattern to be formed, forming a protective resist layer of a desired pattern on the metal layer, and then etching. To obtain a conductor pattern body having a desired shape, and then to form a plated metal layer on the peripheral surface of the conductor pattern body exposed by peeling off the protective resist layer in order to form a conductor pattern having a predetermined thickness. And a method for manufacturing a TAB tape. In the present invention having such a configuration, the metal layer to be etched is a metal foil attached to a flexible resin film via an adhesive layer, or a resin film having a metal layer to be etched is formed, The TAB tape can be manufactured at low cost by using a flexible resin film directly bonded to the metal foil by casting.

Further, according to the present invention, when a lead frame in which inner leads of a predetermined shape are formed by etching a thin metal plate is used, the thin metal plate is thinner than the inner lead to be formed. While using a metal thin plate, after forming a protective resist layer of a desired pattern on the metal thin plate, etching the metal thin plate to obtain an inner lead body of a desired shape, and then forming an inner lead of a predetermined thickness Therefore, in the lead frame manufacturing method, a plated metal layer is formed by plating on the peripheral surface of the inner lead body exposed by peeling off the protective resist layer. In the present invention having such a configuration, by forming protective resist layers on both sides of the metal thin plate and then performing etching from both sides of the metal thin plate, it is possible to reduce the protrusion protruding to the side surface of the inner lead to be formed. The cross-sectional shape of can be as rectangular as possible.

[0009]

Conventionally, when a TAB tape or a lead frame (hereinafter sometimes referred to as a TAB tape or the like) is manufactured by etching, a narrow-pitch conductor pattern or inner lead (hereinafter sometimes referred to as a conductor pattern or the like). In order to obtain the TAB tape or the like in), it is necessary to reduce the thickness of the metal layer or the like to be etched, but the strength of the formed conductor pattern or the like decreases and the conductor pattern or the like is easily deformed. It becomes difficult to handle the obtained TAB tape or the like. On the other hand, if you increase the thickness of the metal layer,
Although it is possible to prevent the strength of the formed conductor pattern or the like from being reduced, it is difficult to manufacture a TAB tape or the like having a conductor pattern of a narrow pitch because the cross-sectional shape of the conductor pattern or the like is substantially trapezoidal.

In this respect, according to the present invention, a metal layer or the like which is thinner than the thickness of the conductor pattern to be formed is etched to form the conductor pattern body or the like having a desired pattern. The cross-sectional shape can be substantially rectangular. Therefore, finally, a conductor pattern or the like having a narrow pitch can be easily formed. In addition, a plated metal layer is formed by plating on the peripheral surface of the formed narrow-pitch conductor pattern body or the like to form a conductor pattern or the like having a predetermined thickness. Therefore, according to the present invention, it is possible to easily form a conductor pattern or the like that has a narrow pitch and is maintained at a predetermined strength, and it is also possible to widen the tip surface of the conductor pattern or the like that is a bonding surface with a semiconductor chip or the like. It is also possible to improve the sex. As described above, according to the present invention, a TAB formed by a conventional etching process that can form a conductor pattern or the like with a narrow pitch while having sufficient strength.
It is possible to simultaneously achieve an antinomy effect that cannot be achieved by the tape manufacturing method.

[0011]

The present invention will be described in more detail with reference to the drawings. FIG. 1 is an explanatory view for explaining the outline of one embodiment according to the present invention, showing a manufacturing process of a TAB tape. First, the copper foil 10 is attached to one surface of the polyimide film 12 via the adhesive layer 14 (FIG. 1A). This copper foil 10
Is thinner than the thickness of the conductor pattern to be formed. Then, after forming the protective resist layer 16 having a desired pattern on the copper foil 10 [FIG. 1 (a)], the polyimide film 12 is immersed in an etching solution to etch the exposed portion of the copper foil 10 to form a conductor pattern body. 18 is molded [Fig. 1
(B)] Further, the protective resist layer 16 is peeled off [FIG.
(C)]. At this time, since the copper foil 10 is thinner than the thickness of the conductor pattern to be formed, the cross-sectional shape of the conductor pattern main body 18 can be made substantially rectangular.

In this embodiment, the conductor pattern body 18 formed by etching the copper foil 10 is electrolytically plated with copper. By such electroplating, as shown in FIG. 1D, the plated metal layer 20 is formed on the peripheral surface of the conductor pattern body 18.
Can be formed, a conductor pattern having a predetermined thickness and width can be obtained, and a predetermined strength can be imparted to the conductor pattern. The thickness of the plated metal layer 20 is preferably about 7-8 μm. In the conductor pattern thus obtained, as shown in FIG. 2, the gap S between the conductor patterns can be made narrower than the thickness H of the conductor pattern and can also have a predetermined strength. Furthermore, since the cross-sectional shape of the conductor pattern is substantially rectangular, the tip end surface serving as a bonding surface can be made wider and the bondability can be improved as compared with the conventional conductor pattern having a substantially trapezoidal cross-sectional shape.

In the process of manufacturing the TAB tape shown in FIG. 1, the copper foil 10 is attached to the polyimide film 12 which has been pressed to form holes such as device holes and window holes, and then the copper foil 10 is etched. There are cases. In this case, as shown in FIG.
Then, the backing resist 24 is filled in and the one side of the copper foil 10 is etched to form the conductor pattern main body 18 [FIG.
(B)]. Next, the protective resist layer 16 and the backing resist 24 are removed to expose the entire circumference of the conductor pattern body 18 facing the hole 22 [FIG. 3 (c)]. After that, the plated metal layer 20 is formed by electrolytic plating over the entire circumference of the exposed conductor pattern main body 18 to form a conductor pattern [FIG. 3 (d)]. In this way, the conductor pattern in which the plated metal layer 20 is formed over the entire circumference of the conductor pattern main body 18 facing the hole 22 is given a predetermined strength and becomes difficult to be deformed, so that the TAB tape can be easily handled. it can.

By the way, the TAB tape is shown in FIGS.
As shown in, a so-called three-layer TAB tape obtained by etching a composite film body having a three-layer structure in which the polyimide film 12 and the copper foil 10 are joined by the adhesive layer 14, and the polyimide film 12 on the copper foil 10. There is a so-called two-layer TAB tape obtained by etching a composite film body having a two-layer structure directly bonded by casting without using an adhesive. The etching process of the present embodiment shown in FIGS. 1 to 3 can be applied to the production of both the three-layer TAB tape and the two-layer TAB tape.

Further, the lead frame having the miniaturized inner leads that can meet the demand for the increased number of pins can be manufactured by the etching process shown in FIG. 4, first, protective resist layers 52, 52, ... With a desired pattern are formed on both surfaces of a metal thin plate 50 having a thickness smaller than that of the inner lead to be formed [FIG. 4 (a)]. After that, both surfaces of the metal thin plate 50 are etched to form the inner lead bodies 54, 54 ... Having a desired shape [Fig.
(B)]. The metal thin plate 50 used in this embodiment is
Since the inner leads to be formed are thinner than the thickness of the inner leads to be formed, the protrusions 55 on the side surfaces of the formed inner lead bodies 54 are small, and the inner cross section of the inner lead bodies 54 can be substantially rectangular. . Further, after the protective resist layers 52, 52 are peeled off [FIG. 4 (c)], the exposed inner lead bodies 54, 54 ... Are electrolytically plated with copper so that the inner lead bodies 54 have a predetermined circumference. A plated metal layer 56 having a thickness is formed [FIG. 4 (d)]. The plated metal layer 56 preferably has a thickness of about 10 to 15 μm.

The inner lead of the lead frame thus obtained, as shown in FIG. 5, can be made thicker than the metal thin plate 50, and can give a predetermined strength to the inner lead. Moreover, since the metal thin plate 50 thinner than the thickness of the inner leads to be formed is used, the inner lead bodies 54 can be formed with a narrow pitch, and the gap distance D between the finally formed inner leads can be narrowed. . Therefore, according to the present embodiment, in combination with the fact that the inner leads can be held at a predetermined thickness, it is possible to obtain a lead frame that has sufficient strength and is provided with inner leads with a narrow pitch. In the above-described embodiment, copper electroplating is used to form the plated metal layer, but electroless plating of copper can also be used to form the plated metal layer with a predetermined thickness. For such electroless plating, for example, CuSO ₄ .6H ₂ O, NCOHO, EDTA.2NA, etc. are blended, and a known thickable electroless plating solution having a pH value of 12.0 to 12.6 is used and the temperature is 70 It can be performed under the condition of ~ 90 ° C.

[0017]

According to the present invention, a TAB having a conductor pattern or inner leads having a narrow pitch and a predetermined strength.
Since the tape or the lead frame can be easily obtained, it is possible to industrially meet the demand for increasing the number of pins.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a method for producing a TAB tape of the present invention.

FIG. 2 is a cross-sectional view showing a cross-sectional shape of a conductor pattern forming the TAB tape obtained by the manufacturing method shown in FIG.

FIG. 3 is a process drawing showing another embodiment of the TAB tape manufacturing method of the present invention.

FIG. 4 is a process drawing showing an embodiment of the method for manufacturing a lead frame of the present invention.

5 is a cross-sectional view showing a cross-sectional shape of an inner lead that constitutes the lead frame obtained by the manufacturing method shown in FIG.

FIG. 6 is a front view showing an example of a TAB tape.

FIG. 7 is a front view showing an example of a lead frame.

FIG. 8 is a process drawing for explaining a conventional TAB tape manufacturing method.

9 is a cross-sectional view showing a cross-sectional shape of a conductor pattern forming the TAB tape obtained by the manufacturing method shown in FIG.

FIG. 10 is a process chart for explaining a conventional lead frame manufacturing method.

FIG. 11 is a cross-sectional view showing a cross-sectional shape of an inner lead forming the lead frame obtained by the manufacturing method shown in FIG.

[Explanation of symbols]

 10 copper foil (metal layer) 12 polyimide film (resin film) 16 protective resist layer 18 conductor pattern body 20 plated metal layer 50 metal thin plate 52 protective resist layer 54 inner lead body 56 plated metal layer

Claims (5)

[Claims] 1. When manufacturing a TAB tape in which a conductor pattern is formed on a flexible resin film, a metal layer thinner than the thickness of the conductor pattern to be formed is formed on one surface of the resin film. , Forming a protective resist layer having a desired pattern on the metal layer, and then performing etching to obtain a conductor pattern main body having a desired shape, and then peeling off the protective resist layer to form a conductor pattern having a predetermined thickness. A method for producing a TAB tape, which comprises forming a plated metal layer on the peripheral surface of the exposed conductor pattern body by plating. 2. The method for producing a TAB tape according to claim 1, wherein the metal layer to be etched is a metal foil attached to a flexible resin film via an adhesive layer. 3. The T according to claim 1, wherein the resin film on which the metal layer to be etched is formed is a flexible resin film directly bonded to the metal foil by casting.
AB tape manufacturing method. 4. When manufacturing a lead frame in which inner leads of a predetermined shape are formed by etching a thin metal plate, a thin metal plate thinner than the thickness of the inner lead to be formed is used as the thin metal plate. In addition, after forming a protective resist layer of a desired pattern on the metal thin plate, the metal thin plate is subjected to etching to obtain an inner lead body of a desired shape, and then, to form an inner lead of a predetermined thickness, A method for manufacturing a lead frame, comprising forming a plated metal layer by plating on the peripheral surface of the inner lead body exposed by peeling off the protective resist layer. 5. The method of manufacturing a lead frame according to claim 4, wherein after forming protective resist layers on both sides of the metal thin plate, etching is performed from both sides of the metal thin plate.