JP2002076066A - Film carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film carrier of which the bonding leads are easily broken in the bonding process and are not broken or bent in the other manufacturing processes. SOLUTION: The film carrier 1 constituted of insulation film 2 and a metal foil (copper foil 5), at least, has the bonding lead 7 for joining electrode 14 of a mounting electronic component, and bonding lead 7 has half-etched portion 11 in the width direction. Hereby, since the bonding lead 7 is easily broken by moving a bonding tool 24 downward and, descending speed of the bonding tool 24 is made smooth. Therefore, it is possible to prevent an occurrence of operational failures of IC chip 30 due to overweight when a bonding portion, bump 13, and electrode 14 are bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a film carrier (T) for mounting an electronic component such as an IC chip on a conductor.
AB (Tape Automated Bonding) tape, a method of manufacturing the same, and a method of manufacturing a BGA type semiconductor package using the film carrier.

[0002]

2. Description of the Related Art Conventionally, electronic devices such as notebook computers, printers, and mobile phones have been reduced in size and weight by mounting electronic components such as ICs and LSI chips on film carriers. Further, with the miniaturization of electronic devices, applications of film carriers that can be used by bending or bending are expanding more and more. This film carrier is manufactured as follows. For example, a copper foil is bonded to an insulating film such as a polyimide resin. A photoresist is applied to the surface of the copper foil, a portion other than the wiring pattern is exposed, and the exposed portion of the photoresist is developed.
Next, the copper foil is etched with an acid to form a desired wiring pattern. Next, after applying a solder resist except for the connection lead, the lead is plated with a metal such as tin which can be alloyed with the electrode of the electronic component. In the film carrier manufactured in this manner, an electronic component is actually mounted in a device hole of the film carrier, and an electrode provided on an electronic component such as an IC chip is bonded to a bonding lead formed on the film carrier. Outer leads are joined to an external wiring board and used for various electronic devices.

FIG. 6 is a plan view showing the structure of a conventional bonding lead. For example, in the case of a bonding process for bonding the bonding leads 7 to the IC chip 30, the materials are alloyed and bonded by pressing the bonding leads 7 with a heated bonding tool 24. As the size of the electronic equipment has been reduced, the size of the film carrier 1 has been required to be small, and the size of the bonding lead 7 has also been reduced, and the lead pitch is 100 to 200 μm. The portion is as thin as about 50 μm. Also, in the current semiconductor packaging, a CSP (chip size package) of almost the same size as an electronic component has been attracting attention for the purpose of thinning and miniaturization, among which a solder ball 31 is arranged on the bottom surface of the package. Then, a BGA (ball grid array) type, which can shorten the wiring length to stabilize the operation and suppress noise, is mainly used.

Until now, as a mounting method of a BGA type semiconductor package, Japanese Patent Laid-Open Publication No. Hei 8-501908 discloses a method in which a film carrier having a pair of V-shaped notches at the side edges of a lead is placed vertically on a tool. Biased, and
A semiconductor inner bonding method has been proposed in which a lead is made S-shaped by moving it horizontally. Further, B
For mounting of the GA type semiconductor packaging, as shown in FIG. 6, a notch portion is provided at a broken edge of the bonding lead at a side edge in a width direction of the bonding lead, so that a There has been proposed a technique for improving productivity by making it easy to be broken and efficient.

[0005]

However, as the size of electronic equipment and the size of the film carrier further decrease, the width of the bonding lead becomes narrower and the width of the notch becomes narrower. In addition, there is a problem that the bonding leads are broken or bent in other manufacturing steps of the film carrier. In the semiconductor inner bonding method proposed in Japanese Patent Application Laid-Open No. 8-501908, a notch is provided at a side edge of a lead portion. If the width of the lead is further reduced, a sufficient depth is obtained by etching. However, there is a problem that the notch portion cannot be formed, and it is difficult to control the size of the notch portion.

Accordingly, an object of the present invention is to provide a carrier film having a bonding lead which does not break or bend in a manufacturing process of a film carrier, but is easily broken by a bonding process. I do. Another object of the present invention is to provide a method for manufacturing a carrier film in which a half-etched portion can be easily provided on a bonding lead. It is still another object of the present invention to provide a method of manufacturing a BGA type semiconductor package using a carrier film having a half-etched portion for a bonding lead.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 comprises at least an insulating film and a metal foil, and has a bonding lead for joining an electrode of a mounted electronic component. A film carrier in which a bonding lead has a half-etched portion in a depth direction. The invention according to claim 2 is the film carrier according to claim 1, wherein the half-etched portion is on one surface of the bonding lead. The invention according to claim 3 is the film carrier according to claim 1 or 2, wherein the thickness of the half-etched portion in the bonding lead is 3 to 20 μm. According to a fourth aspect of the present invention, in the film carrier according to any one of the first to third aspects, the thickness of the bonding lead is 8 to 75 μm.
And a film carrier having a bonding lead width of 10 to 100 μm. An invention according to claim 5, which is a method for producing a film carrier comprising at least an insulating film and a metal foil, comprising applying a photoresist, exposing the photoresist, and then developing the photoresist. Forming a wiring pattern and a bonding lead by etching a film carrier developed by developing a part of a photoresist on a metal foil on which a bonding lead is to be formed. It is. The invention according to claim 6 is a method for manufacturing a film carrier according to claim 5,
The width of a part of the photoresist to be removed is 0.1 to 10
μm is a method for producing a film carrier.

According to a seventh aspect of the present invention, an electronic component having electrode bumps is arranged at least below a film carrier composed of an insulating film and a metal foil,
This is a method of manufacturing a BGA type semiconductor package in which a bonding tool is pressed against a bonding lead of a film carrier and lowered to break the bonding lead and to bond the electrode bump by thermocompression bonding. According to an eighth aspect of the present invention, in the method of manufacturing a BGA type semiconductor package according to the seventh aspect, the bonding lead has a half-etched portion in a depth direction.
This is a method for manufacturing an A-type semiconductor package.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view schematically showing the configuration of the film carrier of the present invention. FIG. 1 (a)
FIG. 1B is a cross-sectional view taken along line AA ′ of FIG. 1A. FIG. 2 is an enlarged view showing the bonding leads of the film carrier shown in FIG.
FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along line BB ′ in FIG. 2A. The film carrier of the present invention is composed of an adhesive film 2 on an insulating film 2 and a wiring pattern 5 of electrolytic copper foil 5.

The insulating film 2 comprises a film carrier 1
In the manufacturing process, various characteristics are required in order to undergo chemical and mechanical processing. For example, heat resistance that does not change even when exposed to a high temperature by bonding, and chemical resistance that does not change even when it comes into contact with an acid by etching, a solvent by washing, or the like is required. Furthermore, it is necessary to be excellent in flexibility because it is often used after being bent. For this purpose, examples of the material for the insulating film 2 include glass epoxy, BT resin, polyester, polyimide resin, and modified products thereof. In particular,
Polyimide resins are preferred. It shows high heat resistance and electrical insulation, and is excellent in flexibility. The polyimide resin is a polymer having an acid imide structure, and examples thereof include a condensation polymer of pyromellitic dianhydride and an aromatic diamine, and a condensation polymer of biphenyltetracarboxylic dianhydride and an aromatic diamine. The thickness of the insulating film 2 is 25
To 120 μm, preferably 50 to 75 μm.

The adhesive used for the adhesive layer 3 needs to have adhesiveness in addition to heat resistance, chemical resistance and flexibility, like the resin. Examples of the adhesive include an epoxy-based adhesive, a phenol-based adhesive, and modified products thereof. Particularly, an epoxy adhesive is preferable. It has excellent adhesion to metal, and excellent electrical insulation and heat resistance. Examples of the curing agent include amines, polyamides, polysulfides, and organic acid anhydrides. These hardeners are added to the epoxy adhesive, applied to the surface of the insulating film 2 or the electrolytic copper foil 5, and the insulating film 2 and the electrolytic copper foil 5 are bonded by leaving or heating at room temperature. The thickness of the adhesive layer 3 is 3
２３23 μm, preferably 10-21 μm.

As the metal foil, a copper foil 5 having excellent conductivity and corrosion resistance is used. Examples of the copper foil 5 include an electrolytic copper foil and a rolled copper foil. In particular, an electrolytic copper foil is preferable because the surface is rough and easily conforms to the adhesive. The thickness of the copper foil 5 is in the range of 8 to 75 μm, preferably 9 to 75 μm, and more preferably 9 to 50 μm. Thus, the thin copper foil 5 is easier to cope with the miniaturization of the outer lead 8. Here, the bonding lead 7 formed by etching the copper foil 5 has a half-etched portion 11 in the depth direction, as shown in FIG.

FIG. 3 is a view showing a step of single bonding the film carrier 1 of the present invention by a bonder. The fed film carrier 1 is fed by a positioned roller along the lower surface of the tape guide. After being aligned with the IC chip 30 on the heating stage 23, the heated bonding tool 24 descends and pushes down the bonding portion of one bonding lead 7, and contacts the electrode 14 provided on the IC chip 30. The electrode bump 13 is bonded. At this time,
The half-etched portion 11 of the bonding lead 7 is cracked and the bonding lead 7 is broken. Here, the half-etched portion 11 is preferably in the depth direction. Since the crack enters from the place where the stress is concentrated, the bonding tool 24 can be lowered smoothly by following the same direction as the bonding tool 24 that moves down. When provided at the side edge of the bonding lead 7, a large stress is required to make a crack, and the bonding tool 2
4 increases in size. Further, when the half-etched portion 11 breaks, the lowering speed of the bonding tool 24 is changed, so that excessive weight is applied at the time of bonding, which damages the IC chip 30 and the like, causes an operation failure, and lowers the reliability of the semiconductor package. Was. Therefore, the bonding lead 7 forming the half-etched portion 11 in the depth direction makes the lowering of the bonding tool 24 smooth, prevents overloading, prevents damage to the IC chip 30 and the like, and improves the reliability of the semiconductor package. Can be improved.

The half-etched portion 11 is preferably provided on one side of the bonding lead 7. This manufacturing method will be described in detail below.
In order to provide the half-etched portions 11 on both sides of the substrate, a step of exposing the photoresist 15 on both sides to form the wiring pattern 5 and a step of developing the photoresist 15 are required. Further, in order to form the half-etched portions 11 from both surfaces, it is difficult to manufacture the two half-etched portions 11 in the same manner. In addition, it is difficult to form a partially-deleted coating surface with a fine width in the application of the screen printing technology, and it is practically impossible to mechanically remove the coating with a fine width after uniform coating. Have difficulty. In any case, forming a protective layer in an etching process having a small width and a part missing in a process other than the etching greatly reduces productivity. Therefore, the half-etched portion 11
Is preferably provided on one side of the bonding lead 7. The half-etched portion 11 has a V-shape,
It may be U-shaped or box-shaped. When the bonding tool 24 is lowered, stress concentrates on the V-shaped or U-shaped bottom, and a crack easily enters. In addition, even if it is a box shape, a crack easily enters from a corner of the box.

The thickness of the half-etched portion 11 at the thinnest point is preferably in the range of 3 to 20 μm. In any of the electrolytic copper foil 5 or the rolled copper foil 5,
The strength is not high because it does not contain many alloy components.
Therefore, if the half-etched portion 11 is 20 μm or more, the film carrier 1 is easily broken or bent during the manufacturing process, and the productivity of the film carrier 1 is reduced. If the thickness is 3 μm or less, it is difficult to break even when the bonding tool 24 is lowered, and the effect of providing the half-etched portion 11 is small. The thickness of the bonding lead 7 is 8 to 75 μm,
Is preferably 10 to 100 mμ. If the thickness of the bonding lead 7 is 8 μm or less or the width of the bonding lead 7 is 10 μm or less, the half-etched portion may be broken or bent in another manufacturing process after etching. The thickness of the bonding lead 7 is 7
5 μm or more or the width of the bonding lead 7 is 100 μm
The above can be dealt with by forming the notch portion.

Next, a method of manufacturing the half-etched portion 11 will be described. The half-etched portion 11 is formed at the same time when the wiring pattern 5, the bonding leads 7, and the outer leads 8 are formed. A photoresist 15 is applied to one or both sides of the surface of the copper foil 5 to which the adhesive is applied. The applied photoresist 15 is exposed with the mask of the wiring pattern 5 suspended, and the exposed portion is developed with a developing solution. next,
The film carrier 1 on which the wiring pattern 5 has been exposed is etched in an etching bath to dissolve the copper in the exposed portion.
Thus, the wiring pattern 5 having the bonding leads 7 and the like on the copper foil 5 is formed. Here, in order to form the half-etched portion 11 on the bonding lead 7, it is necessary to develop a part of the photoresist 15 on the copper foil 5 on which the bonding lead 7 is formed. Then, development is performed with a developer using a mask having a pattern that forms the half-etched portion 11. Next, by etching in an etching bath, the half-etched portion 11 is formed simultaneously with the wiring pattern 5 and the like.
This is equally possible whether the formation of the wiring pattern 5 is positive or negative.

FIG. 4 is a schematic diagram showing a photoresist partially developed on a copper foil on which bonding leads are formed. The film carrier 1 is etched while moving through the etching bath at a constant speed. The etching solution is ammonium persulfate, ferric chloride, ferric chloride
Copper or the like can be used. In particular, it is preferable to use a cupric chloride aqueous solution as a main component. In addition, the etching bath stirs the etchant with a stirring blade or the like. The etching time can be shortened by bringing the etching solution having a low concentration of dissolved copper ions into contact with the surface of the copper foil 5 in which the solution is dissolved. However, in order to form the half-etched portion 11, the photoresist 15 is only partially developed in the portion 15.
a and the photoresist 15 to completely develop the copper foil 5.
Is developed, the circulation of the etching solution is different even when the etching solution is agitated. Therefore, the photoresist 15 has a portion 15a in which only a part has been developed.
Is narrower, so that the dissolved copper ions stay there, so that the copper dissolution rate is lower than that of the portion 15b where the other photoresist 15 is developed. for that reason,
Even if the etching is performed for the same time, the etched amount is different between the portion 15a where the photoresist 15 is partially developed and the portion 15b where the other photoresist 15 is developed,
The bonding lead 7 and the half-etched portion 11 can be formed simultaneously.

The size of the half-etched portion 11 can be controlled by the concentration of cupric chloride in the etching solution, the temperature of the etching solution, the etching time, and the like. Here, in particular, the concentration of the cupric chloride in the etching solution is 1 g / g.
L or less, the temperature of the etching solution is preferably 25 to 50 ° C., and the etching time is preferably 1 to 4 minutes. Thereby, when the thickness of the copper foil 5 is 6 to 75 μm, it can be completely etched, and the thickness of the half-etched portion 11 can be in the range of 3 to 20 μm. Further, the width of the portion 15a obtained by developing only a part of the photoresist 15 is preferably 0.1 to 10 μm. This is because the width of the half-etched portion 11 is 1 to 5 times the width of the photoresist 15 to be developed. Thus, the half-etched portion 11 that can be easily broken by the bonding tool 24 can be manufactured. Also,
Although the half-etched portion 11 covering the entire width of the bonding lead 7 has been described, a groove is provided as the half-etched portion 11 in the bonding lead 7 by removing or leaving the photoresist 15 in an island shape. You may. This is because the groove provided on the surface of the bonding lead 7 is a portion where stress due to the load of the bonding tool 24 is concentrated, and the bonding lead is easily broken.

Next, a BGA using the film carrier 1
The semiconductor package will be described. FIG. 5 is a schematic diagram showing the structure of the BGA type semiconductor package of the present invention. B to perform surface mounting on a circuit board or the like using solder balls
In the GA type semiconductor package 40, the film carrier 1
An electronic component such as an IC chip 30 is mounted on the device. This mounting is performed using a backing material 33 having an adhesive surface. next,
The electrodes 14 provided on the mounted IC chip 30 are bonded to the bonding leads 7 of the film carrier 1 by bonding. After bonding, the bonding leads 7
Is sealed with resin 32 in order to protect. Then, a large number of wiring solder balls 31 are mounted on the IC chip 30. Then, it is cut from the film carrier 1 and used for actual use.

As the backing material 33 used here, silicone resin can be used, but vulcanized rubber is particularly preferable. By providing the backing material 33, the IC
The heat generated during the operation of the chip 30 can absorb the stress caused by the difference in the coefficient of thermal expansion between the insulating film 2 and the copper foil 5. Here, as shown in FIG. 5, since the bonding leads 7 are easily broken by the bonding of the bonding leads 7 of the film carrier 1 and the electrodes of the IC chip 30, the bonding tool 24 smoothly descends and performs bonding. Because of the overweight I
An operation failure due to damage to the C chip or the like can be prevented, and the reliability of the BGA type semiconductor package 40 can be improved.

[0021]

(Embodiment 1) An embodiment of the present invention will be described below.
A desired shape is formed by punching a polyimide resin film having a thickness of 50 μm. Next, an electrolytic copper foil 5 having a thickness of 18 μm is adhered to the adhesive layer 3. A photoresist 15 is applied on the electrolytic copper foil 5 and exposed. At this time, the photoresist 15 on the copper foil 5 on which the bonding leads 7 are formed is partially developed with a width of 1 μm. next,
Etching was performed at 35 ° C. using an etching solution of cupric chloride. The etching time was 1 minute, and etching was further performed for 20 to 30 seconds after the copper foil 5 on the film was lost.
Thereby, the width of the bond portion is 25 μm and the thickness is 16 μm.
The half-etched portion 11 has a width of 10 μm and a thickness of 1
The bonding lead 7 has a thickness of 0 μm. The interval between the bonding leads 7 is 25 μm. After that, a gold plating layer having a thickness of 0.5 μm is formed on the surface of the bonding lead 7. The IC chip 30 is mounted thereon, and the bonding leads 7 and the electrodes 14 of the IC chip 30 are joined to obtain the film carrier 1. Using this film carrier 1, a single bonding type bonder (4522:
(Curic and Sofa)
0 is mounted and bonding is performed. At this time, no operation failure occurred due to the overload of the bonding tool 24.

[0022]

As described above, in the film carrier of the present invention, by providing the bonding lead with the half-etched portion, the bonding lead is easily broken by the lowering of the bonding tool, and the lowering speed of the bonding tool is smooth. Therefore, it is possible to prevent an operation failure of an electronic component such as an IC chip due to excessive load of the bond portion and the bump. Further, in the method for manufacturing a film carrier of the present invention, the half-etched portion can be provided on the bonding lead in the same manufacturing process as that of the conventional film carrier. In addition, the BG of the present invention
The A-type semiconductor package improves reliability by preventing the occurrence of operation failure of an electronic component such as an IC chip due to the overload of the bond portion and the bump due to the easy lowering of the bonding tool due to the easy breakage of the bonding lead. be able to.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a configuration of a film carrier of the present invention.

FIG. 2 is an enlarged view of a bonding lead portion of the film carrier shown in FIG.

FIG. 3 is a view showing a step of performing single bonding of the film carrier of the present invention using a bonder.

FIG. 4 is a schematic view showing a photoresist in which a part is removed on a copper foil on which bonding leads are formed.

FIG. 5 is a schematic view showing a structure of a BGA type semiconductor package.

FIG. 6 is an enlarged view showing a conventional bonding lead portion having a half-etched portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Film carrier 2 Insulating film 3 Adhesive layer 5 Copper foil or wiring pattern 7 Bonding lead 8 Outer lead 9 Sealing resin 11 Half etching part 12 Notch part 14 Electrode bump 15 Photoresist 15a One of the photoresists for producing a bonding lead The part where the part has been removed 15b The part where the photoresist has been removed for the production of the bonding lead 20 Film carrier transport roller 21 Film carrier take-up roller 22 Thermal insulator 23 Heating stage 24 Bonding tool 30 IC chip 31 Solder ball 32 Sealing resin 33 Back Adhesive 40 BGA type semiconductor package

Claims (8)

[Claims] 1. A film carrier comprising at least an insulating film and a metal foil and having an inner lead for joining an electrode of an electronic component to be mounted, wherein the bonding lead has a half-etched portion in a depth direction. A film carrier characterized by the following. 2. The film carrier according to claim 1, wherein the half-etched portion is on one side of the bonding lead. 3. The film carrier according to claim 1, wherein the thickness of the half-etched portion of the bonding lead is 3
A film carrier having a thickness of from about 20 μm to about 20 μm. 4. The film carrier according to claim 1, wherein the thickness of the bonding lead is 8 to 75 μm, and the width of the bonding lead is 10 to 100 μm. 5. A method for producing a film carrier comprising at least an insulating film and a metal foil, comprising applying a photoresist, exposing the photoresist, and then developing the photoresist, and a film developed from the photoresist. A method of manufacturing a film carrier, comprising the steps of: forming a wiring pattern and bonding leads by etching the carrier, wherein a part of a photoresist on a metal foil on which the bonding leads are formed is developed. Production method. 6. The method for manufacturing a film carrier according to claim 5, wherein the width of a part of the photoresist to be removed is 0.1 to 10 μm.
m. 7. An electronic component having electrode bumps is disposed below a film carrier composed of at least an insulating film and a metal foil, and a bonding tool is pressed against an inner lead of the film carrier to lower the bonding lead. And manufacturing the BGA type semiconductor package by thermocompression bonding to the electrode bumps. 8. The method of manufacturing a BGA type semiconductor package according to claim 7, wherein the bonding lead has a half-etched portion in a depth direction.