JP3261064B2 - Method of manufacturing flexible circuit board for semiconductor device - 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 of manufacturing a flexible circuit board for a semiconductor device which can be used as an interposer when a semiconductor device such as an IC chip is mounted on a circuit board. The present invention relates to a method of manufacturing a flexible circuit board for a semiconductor device which is suitable for a chip scale package or a chip size package (CSP) type having a low cost, a high dimensional accuracy, and excellent mass productivity.

[0002]

2. Description of the Related Art As shown in FIG. 3, this type of CSP has a structure in which, when an IC chip is surface-mounted on a counterpart circuit board PCB, an interposer is previously provided on the connection side of the IC chip.
There is a type in which a small-sized flexible circuit board commonly referred to as “A” is connected and joined, and mounted on a circuit board PCB via the flexible circuit board.

[0003] Such a flexible circuit board for a semiconductor device is an I-type flexible circuit board.
A required wiring pattern 21 is provided on the outer surface of the base insulating layer 20 formed to be about the same size as the C chip or slightly larger than the C chip.
A connecting bump 24 for connecting to the C chip is provided, and a solder bump 25 for connecting to the circuit board PCB is provided on the other surface. A predetermined region on the outer surface of the wiring pattern 21 is a surface insulating layer 23. Further, an adhesive layer 22 is provided on the IC chip side of the base insulating layer 20 to form an IC.
It is configured such that the chip and the flexible circuit board can be appropriately joined. Reference numeral 26 denotes a sealing resin layer for an IC chip.

Here, the base insulating layer 20 and the surface insulating layer 23 can be formed by laminating a resin film with an adhesive or by applying and curing a thermosetting or thermoplastic resin. Prior to forming the connection bumps 24 and the solder bumps 25, required openings are formed in the base insulating layer 20 and the surface insulating layer 23.

[0005] Such openings are formed by punching, drilling or laser processing, wet etching with alkali or the like, photolithography of resin having photosensitivity to the resin itself, and plasma processing. It is formed by a processing technique such as dry etching using the like.

[0006]

In the case where the above resin film with an adhesive is used, the film having a required shape is previously formed in the film by means of a punch, a drill, a laser or the like. However, for a means such as a punch or a drill, the practical limit is about 0.3 mm as the hole diameter. Further, when the processed film obtained by such means is laminated, there is a problem that the adhesive melts due to the effect of heat applied at the time of lamination and partially blocks the bottom of the hole.

[0007] Further, the positional accuracy of the wiring pattern 21 with the holes, slits and the like at the time of bonding is ± 0.2 mm to ± 0.2 mm.
Since 0.3 mm is a practical limit, an opening is previously formed in a flexible circuit board used for a semiconductor package such as a wiring pattern having a width of 50 μm and an accuracy between the wiring pattern and a hole of ± 10 μm. It is extremely difficult to apply a method of laminating a processed film.

Therefore, if a laser controlled by NC is applied to the processing of the shape of the opening such as a hole or a slit, the hole diameter becomes 50 μm.
Although good processing properties can be obtained with m and position accuracy of about ± 10 μm, this method is high in processing cost and poor in mass productivity.

Although it is possible to apply a liquid photosensitive resin widely used in the manufacture of semiconductors and obtain a required shape with high precision by a so-called photolithography method, the process is complicated. In addition, since the resin has a photosensitive group, there is a problem that chemical resistance, heat resistance and mechanical properties are inferior to those of a pure film.

Accordingly, the present invention provides a flexible circuit board for a semiconductor device of this type, which is provided with a hole and a slit having a required shape in a low cost while ensuring high positional accuracy and dimensional accuracy. An object of the present invention is to provide a method of manufacturing a flexible circuit board for a semiconductor device, which can obtain a high-quality product by processing in a short time.

[0011]

For this purpose, in the method of manufacturing a flexible circuit board for a semiconductor device according to the present invention, a surface insulating film in which a resist layer and a resin layer are integrated is prepared. The resin layer side is adhered to the wiring pattern side of the flexible circuit board, then the resist layer is processed into a required pattern shape, and the resin layer is processed by the obtained resist pattern. Thus, a surface insulating layer is formed.

The thus obtained flexible circuit board for a semiconductor device can be used as an interposer for a semiconductor package. The resist layer can be made of a photosensitive material, and the resin layer can be made of a semi-cured resin such as a polyimide precursor.

Further, the surface insulating layer as described above can be formed before or after formation of bumps necessary for the flexible circuit board.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in further detail with reference to the illustrated embodiments. First, FIGS. 1 (1) to 1 (10) are manufacturing process diagrams of a flexible circuit board for a semiconductor device according to one embodiment of the present invention. As shown in FIG. A single-sided non-adhesive conductive foil-clad laminate comprising a conductive foil 1 and an insulating base layer 2 such as a polyimide film having a thickness of 25 μm is prepared, and as shown in FIG. A pattern 3 is formed.

Next, as shown in FIG. 3C, a surface insulating film in which the resin layer 4 and the resist layer 5 are integrated is prepared in advance, and the resin layer 4 side is uniformly formed on the wiring pattern 3 side. Paste in. Here, a photo-sensitive material can be used for the resist layer 5, and the resin layer 4 is used for electronic components such as various resins in a semi-cured state, for example, a polyimide resin, an epoxy resin, or an acrylic resin. Can be used.

Therefore, as shown in FIG.
Then, exposure and development processes are performed to form a desired shape, and then a portion of the resin layer 4 exposed by the resist pattern 6 obtained as shown in FIG. The required slits 7 and openings 8 are formed in the lever resin layer 4.

Next, as shown in FIG. 6 (6), after the resist pattern 6 is peeled off, a curing treatment is applied to the resin layer 4 to cure the resin layer 4, thereby forming a surface insulating layer in which the slits 7 and the openings 8 are formed. it can. Next, a thermoplastic polyimide resin or the like is applied to the outer surface of the insulating base layer 2 as shown in FIG.
The resin is cured to form the thermoplastic resin layer 9.

Therefore, as shown in FIG.
At the stage where a hole 10 for forming a bump reaching a predetermined portion of the wiring pattern 3 from the outer surface side of the thermoplastic resin layer 9 is appropriately formed by means of a laser or the like, as shown in FIG. Each hole 10 is filled with a conductive member by plating means or the like to form a required bump 11.

Generally, a product can be obtained by forming a surface plating layer 12 of gold or the like on the exposed surface of the wiring pattern 3 as shown in FIG.

In the above series of steps, for example, the above members in the form of a tape carrier are sequentially fed out, and each step is continuously processed.
After the IC chip is mounted on the other side, the outer shape punching process can be performed.

FIGS. 2 (1) to (10) are process diagrams of manufacturing a flexible circuit board for a semiconductor device according to another embodiment of the present invention. As shown in FIG. Conductive foil 1
Then, a single-sided non-adhesive conductive foil-clad laminate comprising the insulating base layer 2 is prepared, and the thermoplastic resin layer 9 is first formed on the outer surface of the insulating base layer 2 as shown in FIG.

Then, at the stage when the required wiring pattern 3 is formed on the conductive foil 1 as shown in FIG. 3 (3), the resin layer 4 and the resist layer 5 are formed in the same manner as described above as shown in FIG. Is prepared in advance, and the resin layer 4 side is uniformly adhered to the wiring pattern 3 side.

Next, as shown in FIG.
At the stage where a hole 10 for forming a bump reaching a predetermined portion of the wiring pattern 3 from the outer surface side of the thermoplastic resin layer 9 is appropriately formed by means of a laser or the like, as shown in FIG. Each hole 10 is filled with a conductive member by plating means or the like to form a required bump 11.

Then, as shown in FIG. 7 (7), the resist layer 5 is exposed and developed in the same manner as in the previous embodiment to form a resist pattern 6 of a required shape, and then obtained as shown in FIG. 8 (8). Resin layer 4 exposed by the resist pattern 6
In the same manner as described above, chemical etching treatment with potassium hydroxide or the like is performed to form the required slits 7 and openings 8 in the resin layer 4.

Next, as shown in FIG. 9 (9), after the resist pattern 6 is peeled off in the same manner as in the above embodiment, a curing process is applied to the resin layer 4 to cure it, whereby the slit 7 and the opening 8 are formed. Since the surface insulating layer formed with can be formed,
A product is obtained by forming a surface plating layer 12 of gold or the like on the exposed surface of the wiring pattern 3 as shown in FIG.

[0026]

According to the present invention, the surface layer is formed by processing the resist layer by the photolithography technique and processing the resin layer according to the pattern obtained thereby, so that the positional accuracy and the dimensional accuracy are improved. A plurality of products can be processed at a time while ensuring the above, and processing at low cost and in a short time is possible.

In addition, since a chemical etching process can be employed for the processing of the resin layer, a high quality hole processing without burrs, scratches or contamination on the wall surfaces of the openings or slits, or contamination or damage to the conductive foil at the bottom of the hole. Can be performed.

Since various polymer precursors can be used for the resin layer, safety management can be achieved while improving processability.

By using the resist layer and the resin layer separated from each other, a pure surface insulating layer having no photosensitive group can be obtained, so that heat resistance, chemical resistance, migration resistance and outgassing can be obtained. And the like can be improved in reliability.

According to the production method of the present invention, since the resin layer does not have an adhesive layer, the heat resistance can be suitably improved as compared with a conventional two-layer surface insulating film composed of an adhesive layer and a resin layer. Can be raised.

[Brief description of the drawings]

1 (1) to 1 (10) are manufacturing process diagrams of a flexible circuit board for a semiconductor device according to an embodiment of the present invention.

FIGS. 2 (1) to (10) are manufacturing process diagrams of a flexible circuit board for a semiconductor device according to another embodiment of the present invention.

FIG. 3 is a conceptual cross-sectional configuration diagram of a CSP including a flexible circuit board for a semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation base layer 2 Conductive foil 3 Wiring pattern 4 Resin layer 5 Resist layer 6 Resist pattern 7 Slit 8 Opening 9 Thermoplastic resin layer 10 Bump forming hole 11 Bump 12 Surface plating layer

Claims (9)

(57) [Claims] 1. A surface insulating film in which a resist layer and a resin layer are integrated is prepared, and the resin layer side of the surface insulating film is affixed to a wiring pattern side of a flexible circuit board. Manufacturing a flexible circuit board for a semiconductor device, wherein a surface insulating layer is formed by processing the layer into a required pattern shape and processing the resin layer with the resulting resist pattern. Law. 2. A required wiring pattern is formed on a conductive foil of a single-sided non-adhesive conductive foil-clad laminate, and the resin layer side of a surface insulating film in which a resist layer and a resin layer are integrated is connected to the wiring. Affixing to the pattern side, then processing the resist layer into a required pattern shape, processing the resin layer with the resulting resist pattern to form a surface insulating layer, A semiconductor comprising a step of forming a bump for reaching a predetermined portion of the wiring pattern from the insulating layer side of the non-adhesive conductive foil-clad laminate to form a bump, and filling the hole with a conductive member to form a bump; A method for manufacturing a flexible circuit board for a device. 3. The method for manufacturing a flexible circuit board for a semiconductor device according to claim 1, wherein the resist layer of the surface insulating film is photosensitive. 4. The method for manufacturing a flexible circuit board for a semiconductor device according to claim 1, wherein the resin layer of the surface insulating film is a resin in a semi-cured state. 5. The method for manufacturing a flexible circuit board for a semiconductor device according to claim 4, wherein the resin layer of the surface insulating film is a precursor of an insulating resin for electronic parts such as a polyimide resin, an epoxy resin or an acrylic resin. 6. A required wiring pattern is formed on a conductive foil of a single-sided non-adhesive conductive foil-clad laminate, and the resin layer side of a surface insulating film in which a resist layer and a resin layer are integrated is connected to the wiring. Affixed to the pattern side, and then formed a hole for forming a bump reaching a predetermined portion of the wiring pattern from the insulating layer side of the single-sided non-adhesive conductive foil-clad laminate, and a conductive member was inserted into this hole. A semiconductor including a step of forming a surface insulating layer by processing the resist layer into a required pattern shape after filling and forming a bump, and processing the resin layer with the obtained resist pattern; A method for manufacturing a flexible circuit board for a device. 7. The method for manufacturing a flexible circuit board for a semiconductor device according to claim 6, wherein the resist layer of the surface insulating film is photosensitive. 8. The method according to claim 6, wherein the resin layer of the surface insulating film is a semi-cured resin. 9. The method of manufacturing a flexible circuit board for a semiconductor device according to claim 8, wherein the resin layer of the surface insulating film is a precursor of an insulating resin for electronic parts such as a polyimide resin, an epoxy resin, or an acrylic resin.