JP2001110854A - Punching die for manufacturing film carrier tape and method of manufacturing film carrier tape by use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a punching die where a punching pin is hardly broken and punched film tailings are restrained from being left in an opening even if the punching pin is very thin and a method of manufacturing a film carrier tape by the use of the punching die. SOLUTION: The tip cutting edge of the punching pin of a punching die is 0.1 to 0.5 mmΦ in diameter and 0.5 to 1.0 mm in thickness in its vertical direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film punching die useful for manufacturing a film carrier tape having minute openings, and more particularly to a punching die for manufacturing a film carrier tape in which breakage of a punch pin is prevented. And a method for manufacturing a film carrier tape using the same.

[0002]

2. Description of the Related Art In recent years, electronic components such as semiconductor devices and flash memories have become increasingly smaller, lighter and more functional.
Characteristics such as high reliability and low price are required. As a semiconductor mounting method for realizing such characteristics, a BGA (Ball Grid Array) system in which minute solder balls arranged in a matrix in a semiconductor mounting package are formed and these solder balls are connected to an external wiring board. The BGA type package materials that use a film carrier tape are also increasing in popularity. In addition, a CSP (C) that reduces the size of a semiconductor mounting package itself to the size of a semiconductor chip
Although a chip size package (HP) is being adopted, a film carrier tape based on the BGA system is becoming popular as a CSP (a tape type CSP).

As a method of manufacturing a film carrier tape by the BGA method such as a tape type CSP, first, a base film tape having an adhesive layer formed on the surface of an insulating resin film such as a polyimide film is provided with holes for solder ball connection. Then, necessary holes such as a sprocket hole for positioning the tape and a positioning hole are punched. afterwards,
It is manufactured by sticking a metal foil such as a copper foil, forming a desired circuit with the metal foil, and performing a necessary surface treatment. BGA film carrier tape is almost the same process as conventional TAB tape except that it has holes for solder balls.
It can be manufactured from materials. The tape width used is generally 35 mm to 96 mm, and as the tape thickness, an insulating resin film is often used in a thickness of 20 to 75 μm, and a metal foil is often used in a thickness of 12 to 35 μm.

The size of the hole for the solder ball is 0.1 to 0.1 mm.
It is about 0.8 mm, arranged in a matrix at a pitch of 0.5 to 2.0 mm.
A 1.0 mm solder ball is attached. After the semiconductor device is connected to the tape CSP by bonding or the like, the semiconductor device is sealed with an epoxy resin or the like by potting or transfer molding to protect the semiconductor device.

[0005] As a method of drilling a hole for a solder ball, an upper die having a structure capable of lowering and rising the punch pin by applying a processing load in the axial direction of one or more punch pins, After placing the base film tape between the lower die having a die having a cutting edge portion diameter larger than the outer diameter of the cutting edge, the punch pin is lowered by the load of the processing load, and a hole is formed in the base film tape. Using a punching die for forming a solder ball hole corresponding to one or a plurality of semiconductor devices or a part of a solder ball hole corresponding to a semiconductor device by one punching, and a tape transporting die. The necessary holes such as sprocket holes and positioning holes were punched and drilled (Japanese Patent Application No. 11-220525).
reference).

[0006]

However, in a situation where the tape type CSP is required to be further reduced in size, increased in density, and reduced in cost, the per-unit area mounted on the film carrier tape is reduced. The need to increase the number of semiconductor devices has arisen. For this reason, the number of solder ball holes per unit area of the base film tape needs to be dramatically increased. That is, the size of the hole for the solder ball itself is conventionally 0.3 to 1.0 m in diameter.
Although mΦ was large, it was required to form a solder ball hole having a diameter of 0.3 mm or less.

According to this request, the diameter of the punch pin of the punching die is reduced to 0.3 mmΦ or less, and punching is performed using the punching die shown in FIG. 2. The problem of breaking occurred. Even if one punch pin is broken, the entire punching die cannot be used. In addition, the punching die is expensive because it is designed for each product, and the manufacturing time is long. This is a major obstacle to mass production.

Further, even if the punch pin is not broken after performing the punching for a predetermined number of times, the hole for the solder ball punched is observed with a microscope, and it is found that the hole is defective.
That is, a hole in which the opening of the hole for the solder ball was incomplete was found in which the scrap of the film remained in the opening hole.

The inventors of the present invention have conducted a detailed examination of the breakage of the punch pin and the defective opening with a microscope. As shown in FIG. 2, the film is attached to the lower cutting edge corresponding to the punch pin having such a defect. It has been discovered that there are many cases where the scrap remains. The film scrap is a fragment of a base film tape having an adhesive layer such as an epoxy resin formed on the surface of an insulating resin film, and tends to expand slightly after being cut by punching. Also,
The adhesive layer is in an uncured state to be adhered to a metal foil such as a copper foil after punching, and thus has an adhesive state. Therefore, it was found that the punching die easily adheres to the lower cutting edge of the punching die or is closed. The present invention has been made in view of such a conventional problem, and an object of the present invention is to enable a large number of fine solder ball holes to be reliably formed in a base film tape, and to form a scrap. An object of the present invention is to provide a punching die that does not break a punch pin or block an opening hole due to adhesion, and to provide a method of manufacturing a film carrier tape for semiconductor mounting having a minute opening hole using the die.

[0010]

According to the present invention, there is provided an upper die having a structure capable of lowering and rising the punch pin by applying a processing load in the axial direction of one or more punch pins, and a tip of the punch pin. Between the lower die having a die having a cutting edge diameter larger than the outer diameter of the cutting edge,
After arranging the base film tape, the punch pin is lowered by the load of the processing load, and in a punching die for forming a hole in the base film tape, the diameter of the tip cutting edge portion of the punch pin is 0.1 to 0. .5m
mΦ, and the vertical thickness of the cutting edge portion of the die is 0.5 to 1.0 mm.

A method of manufacturing a film carrier tape according to the present invention is characterized by using the above-mentioned punching die.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The punching die for a film carrier tape of the present invention and a method for manufacturing a film carrier tape using the same will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a base film tape which is placed between a lower mold 4 and an upper mold 5 and formed at both ends of the tape. It is fixed by a positioning pin (not shown) engaged with a positioning hole such as a sprocket hole. A signal from a control panel (not shown) moves in a feed direction 9 at predetermined intervals.
Sent sequentially. The number of solder ball holes perforated by one punching die is suitably in the range of 100 to 800, and the punching die has a number of punch pins corresponding to the number of holes. Only one of them is shown.

Reference numeral 2 denotes a punch pin which is a tool for perforating the base film tape 1 and has a tip cutting edge 2a.
Is the same as the diameter of the hole to be drilled. In addition, punch pin 2
Is guided by an inner diameter portion of a punch pin guide 7 press-fitted and fixed to the upper die 5, and is lowered by a processing load 6 applied from a pressing device (not shown) to pierce the base film tape 1. The length of the punch pin to be inserted into the cutting edge portion of the die 3, that is, the stroke is preferably 0.3 to 0.8 mm. If the length is longer than 0.8 mm, the punch pin is easily broken. And the like tend to occur.

The lower die 4 has a base film tape mounted thereon, and the perforating die 3 is fixed by fitting the outer diameter of the die 3 and the die fixing hole 4C. The inner diameter of the cutting edge 3a of the die 3 is larger than the outer diameter of the tip cutting edge 2a of the punch pin 2, and when the punch pin 2 descends, the tip cutting edge 2a of the punch pin 2 is inserted into the cutting edge 3a of the die 3. By doing so, the base film tape 1 is subjected to a shearing process so that the film scrap 1b is dropped to form a hole for a solder ball. The inner diameter of the cutting edge 3a is larger by 0.002 to 0.01 mm on one side than the diameter of the hole to be drilled.

The vertical thickness t of the cutting edge portion 3a of the die 3 exceeds 1.0 mm in a conventional punching die,
0.5 to 1.0 mm in the punching die of the present invention
Is a characteristic. The surface of the lower mold 4 is polished as necessary to smooth the surface irregularities caused by continuous use of the punching mold or to remove an oxide layer on the surface. If the thickness t in the direction is smaller than 0.5 mm, the life as a punching mold is shortened, which is not desirable.

It is desirable that the inner diameter of the cutting edge 3a of the die 3 is increased from the upper part to the lower part of the cutting edge 3a as shown in FIG. That is, the inner diameter of the lower part is set to be 1 to 10% wider than that of the upper part. In this way, the film scrap is more easily dropped. However, if the inner diameter of the lower portion is wider than 10%, the upper portion of the cutting edge portion 3a is sharpened, and the strength is undesirably reduced.

[0018]

EXAMPLES Next, a method for manufacturing a film carrier tape using the mold will be specifically described with reference to Examples.
The present invention is not limited by these. First, a base film tape in which an adhesive layer in a semi-cured state (B stage) is formed on the surface of an insulating resin film such as a polyimide film is placed on the surface of the lower mold 4. The surface of the adhesive layer is covered with a protective film for preventing attachment of dust and impurities.

As the base film tape, tape width 4
8mm, 75μm thick polyimide film (trade name:
A sheet-like epoxy-based adhesive (trade name: X, manufactured by Hamakawa Paper Co., Ltd.) bonded to IUPIREX S (manufactured by Ube Industries, Ltd.) by thermocompression bonding was used. A sprocket hole and a hole for a solder ball were formed in the base film tape by using a punching die shown in FIG. The punching die has 294 (7 × 7 × 6) punch pins for solder balls.

The diameter of the cutting edge portion 2a of the punch pin 2 is equal to 0.1.
24 mmΦ. The vertical thickness t of the cutting edge 3a was 0.8 mm. After the base film tape is placed as described above, a necessary processing load is applied in the axial direction of the punch pin 2, and the punch pin 2 is moved down to lower the solder ball hole 29.
Four were drilled. The stroke was 0.5 mm. The punching speed was 80 shots / min. After punching, the base film tape was transported at a predetermined pitch, and punching was sequentially performed.

The punching is continued in this manner, and after exceeding 20,000 shots, 100,000 shots, 200,000 shots, and 300,000 shots, five punching samples are cut out from the base film tape, and the opening holes are formed using a microscope. As a result of inspection, no opening failure such as non-opening due to punch pin breakage and residual film removal residue did not occur. Further, when the shape of the punched solder ball hole was observed with a scanning electron microscope, no burrs or deformation of the hole shape were found.

The base film tape has a thickness of 15 μm.
m, an electrolytic copper foil (trade name: FQ-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a width of 43 mm was laminated at 160 ° C. in an oven.
Heated for 10 hours. The tape after heating, according to a standard method, application of a photosensitive photoresist, circuit pattern exposure,
Development and copper etching were performed to form a copper circuit pattern. Next, the obtained tape was transferred to a plating layer, and 0.1 μm thick gold plating was applied to the exposed copper foil surface portion where the solder resist of the tape was not applied, to obtain a film carrier tape for semiconductor mounting. .

[0023]

As described above, according to the present invention, when a hole for a solder ball is punched in a base film tape, a chip from the film does not adhere to or clog the cutting edge of the die. There is no problem such as breakage, and the life of the punching mold is extended to the extent that mass production of the film carrier tape is sufficiently possible. Further, by using this mold, it is possible to avoid poor electrical conduction of the solder balls due to the residual film removal residue, so that a highly reliable method of manufacturing a film carrier tape can be provided.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a punching die to which the present invention is applied.

FIG. 2 is a front sectional view of a conventional punching die.

[Explanation of symbols]

1: Base film tape, 1a: Solder ball hole, 1
b: film scrap, 2: punch pin, 2a: cutting edge of punch pin, 3: die, 3a: cutting edge of die, 4:
Lower mold, 4c: Die fixing hole, 5: Upper mold, 6: Processing load,
7: Punch pin guide, 8: Feed direction

Claims (2)

[Claims] 1. A punching pin is lowered by applying a processing load in the axial direction of one or more punch pins.
After disposing a base film tape between an upper mold having a structure capable of ascending and a lower mold having a die having a cutting edge portion diameter larger than the outer diameter of the cutting edge at the tip of the punch pin, the processing is performed. In a punching die for forming a hole in the base film tape by lowering the punch pin by applying a load, a diameter of a tip cutting edge portion of the punch pin is 0.1 to 0.5 mmΦ, and A punching die for a film carrier tape, wherein a vertical thickness of a cutting edge portion is 0.5 to 1.0 mm. 2. A method for manufacturing a film carrier tape using the punching die according to claim 1.