JP3324472B2 - Method for manufacturing TAB tape for BGA - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TAB (Tape Automat) mounting a semiconductor element such as an IC or an LSI.
More particularly, the present invention relates to a method for manufacturing a TAB tape suitable for a BGA (Ball Grid Array) type package.

[0002]

2. Description of the Related Art As a conventional method of manufacturing a TAB tape for BGA, for example, a method of forming via holes and device holes by laser processing is known.

In this manufacturing method, a metal foil is formed on both sides of an insulating film such as a polyimide serving as a base film, and then the metal foil on one side is first subjected to an etching treatment.
Thereby, a hole of a predetermined pattern is provided on the metal foil on one side, and then a via hole and a device hole corresponding to the hole shape of the predetermined pattern are formed by irradiating the metal foil with a CO ₂ laser or the like. Formed on the insulating film, then, after forming a metal plating from the metal foil on one side to the inner surface of the via hole, by etching the metal foil on the other side to form a wiring layer of a predetermined shape, The production proceeds by providing solder balls on one side.

[0004] This manufacturing method based on laser drilling is not only excellent in processing accuracy, but also has a remarkably advantageous work efficiency in comparison with an alkali etching method or the like which is excellent in processing accuracy. From
It is used as an effective manufacturing method.

[0005]

However, according to such a conventional method of manufacturing a TAB tape for BGA, the laser output must be set to a considerably high level in order to form a large-sized device hole. Therefore, there is a problem that a via hole having a small size formed simultaneously with the device hole deforms the inner surface shape.

FIG. 4 shows a state in which a via hole 5 is formed by a laser 18 passing through a hole 6 ′ of the copper foil 1.
The cross-sectional shape of the via hole 5, which should be originally formed as indicated by the dotted line 19 with respect to the insulating film 2, is deformed (etched back) as indicated by 20 due to excessive laser output. For this reason, the quality as a via hole may be impaired.

Further, according to the conventional TAB tape for BGA, when a semiconductor element is mounted and then connected to an external circuit such as a printed circuit board, stress due to thermal expansion and contraction is concentrated on the solder ball, and the wire is broken at that portion. Might be.

Accordingly, it is an object of the present invention to provide a method of manufacturing a TAB tape for BGA, which can be performed uniformly without deforming the formation of via holes in an insulating film.

Another object of the present invention is to provide a method of manufacturing a TAB tape for a BGA, which can manufacture a TAB tape for a BGA having high reliability in which a solder ball is not disconnected even when subjected to stress due to thermal expansion and contraction. I do.

[0010]

In order to achieve the above object, the present invention has solder balls arranged in an array in a predetermined pattern as terminals for connection to an external circuit. In a method of manufacturing a TAB tape for BGA having a via hole of a pattern corresponding to a pattern and a device hole for mounting a semiconductor element, a first metal layer is provided on a first surface, and an adhesive layer is provided on a second surface. The second surface of the insulating film on the second surface by the adhesive layer;
Before the bonding, the via hole and the device hole are formed by punching, and at least the inner wall surface of the via hole and its periphery have a thickness corresponding to the temperature and time of soldering of the solder ball. The second metal layer is processed into a wiring layer of a predetermined pattern, and the soldering temperature and the via hole are formed on the first surface of the insulating film via the conductive plating. Another object of the present invention is to provide a method of manufacturing a TAB tape for BGA, wherein the solder balls are soldered according to time.

According to another aspect of the present invention, there is provided a BGA TAB having solder balls arranged in an array in a predetermined pattern as terminals for connection to an external circuit.
In a method of manufacturing a tape, a first metal layer is provided on a first surface, and an insulating film having an adhesive layer on a second surface is punched to form a via hole having a punched pattern corresponding to the predetermined pattern, A second metal layer is bonded to the second surface of the insulating film by the adhesive layer, and the first metal layer is processed to form a hole having a predetermined shape, and a laser is irradiated from the hole. Forming a device hole corresponding to the shape of the hole in the insulating film, and forming a conductive film having a thickness according to the temperature and time of soldering the solder ball on at least the inner wall surface and the periphery of the via hole. Covering plating, processing the second metal layer to form a wiring layer of a predetermined pattern,
A method of manufacturing a TAB tape for BGA, wherein the solder ball is soldered to the via hole via the conductive plating according to the temperature and time of the soldering.

In the former manufacturing method, the formation of the via hole and the device hole is performed before or after the bonding of the second metal layer to the second surface of the insulating film as described above. However, these via holes and device holes are not always formed at the same time.

Although the device hole is usually formed before the second metal layer is bonded, the formation of the via hole is not particularly limited before and after the bonding.

[0014]

The manufacturing method is effective when forming a device hole by laser processing, and since the metal plating is formed on the inner surface of the via hole before laser irradiation, the via hole has a high output for processing the device hole. It is not affected by laser.

As the constituent material of the insulating film, a heat-resistant material such as polyimide or polyamide imide is used. As the material forming the first and second metal layers, a copper foil, a copper alloy foil, or the like is used. Is used.

As a method of forming the first metal layer on the first surface of the insulating film, a method that does not use an adhesive is desirable. Specifically, the material of the insulating film is applied to the first metal layer. Direct casting is preferred.

The adhesive layer provided on the second surface of the insulating film is formed, for example, by applying an adhesive obtained by dissolving a curable resin such as an epoxy resin in a solvent and drying the adhesive. The thickness differs depending on the connection type between the inner lead of the wiring layer and the semiconductor element to be mounted.

The connection between the inner lead of the wiring layer (second metal layer) bonded to the insulating film by this adhesive layer and the mounted semiconductor element is performed by wire bonding performed at a high temperature such as 200 ° C. It is preferable that the thickness of the adhesive layer is as thin as possible,
The thickness is desirably set to 7 μm or less, but when the inner lead and the semiconductor element are connected by inner lead bonding (TAB connection) using bumps, the thickness may be increased to a maximum of 50 μm. It is possible.

When a polyimide film is used as the insulating film, it is desirable that the polyimide film has a thickness of at least 20 μm in order to ensure a practical level of electrical insulation and strength during tape transport. When the metal layer is integrated by casting, it is desirable to set a thickness of 75 μm as an upper limit value in order to secure casting properties.

As the second metal layer constituting the wiring layer,
It is desirable that the copper foil is 35 μm or less.
In particular, when forming a so-called fine-pitch wiring by photoetching, which is required to have a wiring pitch of 80 μm or less, this is a preferable upper limit for ensuring this.

The size of the via hole is 50 to 500 μm in diameter.
m, and the device hole varies depending on the size of the semiconductor element to be mounted.
Its size is about 10 mm square.

A solder ball formed by soldering on the first surface of the insulating film via conductive plating, when connected to an external circuit such as a printed circuit board after mounting a semiconductor element, has a stress due to thermal expansion and contraction. There is a possibility of disconnection due to the intensively receiving of the conductive film, but in order to prevent this, the thickness of the conductive plating formed on the inner wall surface of the via hole and its periphery is important.

It is necessary that the thickness be determined in accordance with the temperature and time when the solder ball is formed in the via hole, and specifically, (245 ± 5) ° C. × (60 ± 1)
0) Having a thickness that can withstand a soldering operation performed under conditions such as seconds is a prerequisite for securing the resistance to the stress.

That is, when the soldering operation of the solder ball is performed under the conditions of (245 ± 5) ° C. and (60 ± 10) seconds, a preferable plating thickness when copper plating is applied as the conductive plating. The height is set in the range of 7 to 10 μm.

A plating layer made of nickel, gold, tin, solder, or the like is formed on the inner pad portion of the wiring layer or the ball pad portion where the solder ball is formed, if necessary.

[0026]

Next, a TA for BGA according to the present invention will be described.
An embodiment of a method for manufacturing a B tape will be described.

FIG. 1 shows a processing procedure in one embodiment of the present invention. First, as shown in (a), a copper foil 1 having a thickness of 18 μm to constitute a ground layer or a power supply layer.
To prepare a polyimide film 2 having a copper foil 1 (first metal layer) formed on its first surface by casting polyimide to a thickness of 50 μm. An adhesive layer 3 mainly composed of a curable epoxy resin was formed to a thickness of 13 μm to form a laminate 4.

Next, the laminate 4 is subjected to a punching process using a mold having a predetermined shape as shown in FIG.
As a result, a via hole 5 having a predetermined pattern of 80 μm in diameter and a 10 mm square device hole 6 for mounting a semiconductor element were formed.

Next, as shown in (c), a copper foil 7 (second metal layer) having a thickness of 25 μm is attached to the adhesive layer 3 and then heated to 140 ° C. Layer 3 was cured.

(D) Desmeared via hole 5
The inner wall surface and its surroundings are covered with a copper plating 8 which is formed to a thickness of 7 μm by electroplating.
As described above, a coating layer 9 made of a 15 μm-thick photo solder resist was formed at a predetermined location.

Further, the copper foil 7 was subjected to a photo-etching process, thereby forming a wiring layer 7 'having a wiring pitch of 80 μm including the inner lead 10, the lead wiring, and the input lead.

Next, as shown in (f), the inner wall surface of the via hole 5 and the surface of the copper plating 8 exposed from the coating layer 9 are covered with a 0.5 μm nickel plating having a thickness of 1 μm as a base. A gold plating 11 having a thickness was formed, and thereby a ball pad portion 12 was provided.

Next, after a coating 13 having a thickness of 15 μm made of a photo solder resist is formed on a predetermined portion of the wiring layer 7 ′, the ball pad portion 12 is
The solder balls 14 were formed by soldering under the conditions of 245 ° C. × 60 seconds, thereby producing a BGA TAB tape having a predetermined structure.

(H) is the B manufactured as described above.
This figure shows the mounting structure of the semiconductor element 15 on the TAB tape for GA. The electrode bump 16 of the semiconductor element 15 is bonded to the inner lead 10 of the wiring layer 7 ′. Thus, a BGA semiconductor package having a predetermined structure was formed.

FIG. 2 shows another embodiment in which device holes and via holes are formed by punching as in FIG. 1. The difference from FIG. 1 in this embodiment is that The point is that the formation times of device holes and via holes are shifted.

That is, as shown in (a), the polyimide film 2 formed by casting and the copper foil 1 (first metal layer) provided on the first surface of this film 2
And the adhesive layer 3 formed on the second surface of the polyimide film 2,
As shown in (b), a 10 mm square device hole 6 was punched out using a mold.

Next, as shown in (c), after bonding the copper foil 7 as the second metal layer to the adhesive layer 3,
As shown in (d), a via hole 5 having a predetermined pattern with a diameter of 80 μm is formed by punching using a mold, and further, photoetching is performed on the copper foil 7 so that the inner lead 10 and the leading wiring can be formed. A wiring layer 7 'including input leads was formed.

Unlike the case of FIG. 1, the via hole 5 in the present embodiment is formed so as to penetrate the entire laminate from the copper foil 1 to the wiring layer 7 '.

Then, after the inner surface of the via hole 5 is desmeared, a 8.5 μm thick copper film is formed from the inner wall surface to a predetermined portion of the copper foil 1 and the wiring layer 7 ′ as shown in FIG. A plating layer 8 is formed on the copper plating 8. Thereafter, a coating layer 9 made of a 15 μm-thick photo solder resist is formed on the copper plating 8 at a predetermined position, thereby forming a ball pad portion 12. ), The solder balls 14 are placed on the ball pad portions 12 of the copper foil 1.
Was formed by soldering under the conditions of 245 ° C. × 60 seconds to obtain a predetermined TAB tape for BGA.

FIG. 3 shows an embodiment of a TAB tape manufacturing method of the present invention in which via holes and device holes are formed by a combination of punching and laser processing.

First, as shown in (a), a material is prepared by casting a polyimide film 2 so as to have a thickness of 50 μm with respect to a copper foil 1 (first metal foil) having a thickness of 18 μm. Then, a laminate 4 was manufactured by forming a curable epoxy-based adhesive layer 3 having a thickness of 13 μm on the second surface of the polyimide film 2.

Next, as shown in (b), a punching process was performed on the laminated body 4 to form a via hole 5 having a predetermined pattern having a diameter of 80 μm.

Next, as shown in (c), a copper foil 7 (second metal layer) having a thickness of 25 μm is attached to the adhesive layer 3 and heated to 140 ° C. 3
After that, as shown in (d), a 10 mm square hole 6 ′ is formed in the copper foil 1 by subjecting the copper foil 1 to photoetching, and the via hole 5 is desmeared. After the treatment, the inner wall surface of the via hole 5 and its periphery were covered with copper plating 8 having a thickness of 10 μm by electroplating.

Next, a device hole 6 having the same shape as the hole 6 'is formed by irradiating the polyimide film 2 with a CO ₂ laser 18 from above as shown in FIG. 7 by subjecting the inner lead 1 to a photo-etching process as shown in FIG.
A wiring pattern 7 ′ having a predetermined pattern including 0, routing wiring, and input leads was formed. Reference numeral 9 denotes a 15 μm-thick photo solder resist coating layer provided at a necessary portion of the copper plating 8.

In (g), 11 is 1 on the copper plating 9.
0.5μ formed through nickel plating of μm thickness
Reference numeral 12 denotes a ball pad portion formed by this, and reference numeral 13 denotes a 15 μm-thick photo-solder resist coating layer formed at a predetermined portion of the wiring layer 7 ′.

Reference numeral 14 denotes a solder ball provided on the ball pad portion 12, and the solder ball 14
The tape was formed under the conditions of 45 ° C. × 60 seconds, and thus a TAB tape for BGA having a predetermined structure was completed.

In the case of this embodiment, the device holes 6 are formed in the polyimide film 2 by laser processing. However, the via holes 5 during laser irradiation are in a state where the inner surfaces thereof are protected by the copper plating 8. Therefore, even if a high-power laser 18 for forming a device hole is received, the inner surface of the via hole 5 is not likely to be deformed. Therefore, this method is not suitable for a processing type in which a device hole is formed by a laser. Is an effective method.

Next, the device is manufactured according to the embodiment shown in FIGS.
A result of performing a characteristic test on each of the BGA TAB tapes formed with eight via holes 5 will be described.

The test was conducted at minus 55 ° C. and plus 150 ° C.
And a heat cycle test in which the temperature was maintained at 30 ° C. for 30 minutes for each cycle.
Conduction resistance was measured at each cycle of 0 cycle and 1,000 cycles, and the change was observed by observing the change. However, the increase of the conduction resistance was observed in any of the TAB tapes manufactured according to FIGS. No solder balls 15 were dropped off, and high thermal stress stability was confirmed.

A migration test with a DC bias of 24 V was performed continuously for 1,000 hours in an environment of a temperature of 85 ° C. and a humidity of 85%, but there was no conduction breakdown in the copper-plated via hole. No dielectric breakdown was observed between them.

[0051]

As described above, the BG according to the present invention is
According to the TAB tape for A, a via hole and a device hole are processed by punching, or a via hole is formed by punching and metal plating is formed on an inner surface thereof, and then a device hole is formed by laser processing. Therefore, there is no intervening factor that causes the via hole to be deformed due to the excessive laser unlike the related art, and therefore, it is possible to provide a TAB tape for BGA having a uniform via hole.

Further, since at least the inner wall surface of the via hole and the periphery thereof are covered with conductive plating having a thickness corresponding to the soldering temperature and the soldering time of the solder ball, the conductive plating is applied. The presence of plating gives a resistance to the solder ball forming portion when stress based on thermal expansion and contraction is concentrated, and therefore, a situation such as disconnection at the solder ball portion due to thermal expansion and contraction stress. It can be prevented beforehand.

[Brief description of the drawings]

FIGS. 1A to 1G are explanatory views of a manufacturing method of a TAB tape for BGA according to the present invention, wherein FIGS. 1A to 1G show the manufacturing procedure, and FIG.

FIG. 2 is an explanatory view of another embodiment of the method of manufacturing a TAB tape for BGA according to the present invention, and (a) to (f) show the manufacturing procedure.

FIG. 3 is an explanatory view of still another embodiment of the TAB tape for BGA according to the present invention, and FIGS.

FIG. 4 is an explanatory view of a problem in a conventional manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper foil 2 Polyimide film 3 Adhesive layer 5 Via hole 6 Device hole 6 'hole 7 Copper foil 7' wiring layer 8 Copper plating 14 Solder ball 18 Laser

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/60 H01L 23/12

Claims (6)

(57) [Claims] 1. A device for mounting solder balls arranged in an array in a predetermined pattern as terminals for connection to an external circuit, and for mounting via holes and semiconductor elements in a pattern corresponding to the predetermined pattern. A method of manufacturing a TAB tape for BGA having a hole, wherein the adhesive is attached to the second surface of an insulating film having a first metal layer on a first surface and an adhesive layer on a second surface. A second metal layer is adhered by a layer, and before the adhesion, the via hole and the device hole are formed by punching, and at least the inner wall surface of the via hole and its periphery are soldered according to the temperature and time of soldering of the solder ball. Covering the conductive plating with a thickness, processing the second metal layer to form a wiring layer of a predetermined pattern, and forming the wiring layer in the via hole on the first surface of the insulating film. Method for producing a TAB tape BGA, characterized by soldering the solder balls by the temperature and time of the soldering through Kishirube conductive plating. 2. The method according to claim 1, wherein the coating of the conductive plating is a copper plating coating having a thickness of 7 to 10 μm, where the temperature and time of the soldering are (245 ± 5) ° C. × (60 ± 10) seconds. 2. The TAB tape for BGA according to claim 1, wherein: 3. The insulating film has a thickness of 20 to 75 μm.
2. The TAB tape for BGA according to claim 1, wherein the second metal layer constituting the wiring layer is a copper foil having a thickness of 35 μm or less. 3. 4. A BGA having solder balls arranged in an array in a predetermined pattern as terminals for connection to an external circuit.
A method of manufacturing a TAB tape for use, comprising: a first metal layer on a first surface; and an insulating film having an adhesive layer on a second surface. The insulating film is punched to form a via hole having a punched pattern corresponding to the predetermined pattern. The second surface of the insulating film is formed on the second surface by the adhesive layer.
The first metal layer is adhered, a hole having a predetermined shape is formed by processing the first metal layer, and a laser hole is irradiated from the hole to form a device hole in the insulating film according to the shape of the hole. Forming at least an inner wall surface of the via hole and its periphery with conductive plating having a thickness corresponding to the temperature and time of soldering the solder ball;
Is processed into a wiring layer of a predetermined pattern, and the solder balls are soldered to the via holes on the first surface of the insulating film via the conductive plating by the temperature and time of the soldering. A method for producing a TAB tape for BGA. 5. The conductive plating coating is a copper plating coating having a thickness of 7 to 10 μm when the soldering temperature and time are (245 ± 5) ° C. × (60 ± 10) seconds. The method for producing a TAB tape for BGA according to claim 4, characterized in that: 6. The insulating film has a thickness of 20 to 75 μm.
5. The method for manufacturing a TAB tape for BGA according to claim 4, wherein the second metal layer constituting the wiring layer is a copper foil having a thickness of 35 μm or less. .