KR20010068515A - Semiconductor package and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A semiconductor package and a manufacturing method thereof are provided to enhance reliability of a semiconductor package by blocking a path through which moisture is infiltrated into an inside of the package from the outside. CONSTITUTION: A beam lead(14) is formed on a base film(13) at a predetermined pattern. The base film(13) is formed of polyimide, for example. The beam lead(14) is a copper wire. Only the gold plated beam lead(14) without a base film is exposed on a tape substrate on a chip pad(12) side. Accordingly, the beam lead(14) can be connected to the chip pad(12) by a pressing power applied from the outside in a physical manner. An encapsulant(18) is filled in the connect part of the beam lead(14) and the chip pad(12). The encapsulant(18) is also formed on an outer wall of the package(10). A cover film(20) is formed on a part of the base film(134) and the encapsulant(18) on the beam lead(14) side. A delamination phenomenon is generated between the encapsulant(18) and the beam lead(14) even under a poor environment like a reliability test. Because of the delamination, moisture is easily infiltrated into an inside of the package. However, the cover film blocks the moisture from being infiltrated into the package.

Description

Semiconductor Package And Manufacturing Method Thereof

The present invention relates to a semiconductor package and a method of manufacturing the same, and more particularly, a semiconductor chip and a tape wiring board are attached to both sides of an elastomer and a beam lead formed on the tape wiring board is electrically connected to the semiconductor chip to be protected by a sealing resin. The present invention relates to a chip size semiconductor package in which a solder ball is formed on a tape wiring board, and a manufacturing method thereof.

The so-called package used in the semiconductor industry refers to a form in which a semiconductor chip in which a microcircuit is formed is sealed with plastic resin or ceramic so that the semiconductor chip can be mounted on an actual electronic device. Therefore, the package manufacturing process may be referred to as a final productization process. The importance of packages is increasing with the trend of high integration and high speed of semiconductor chips, and they are being developed in the direction of high density, high speed, miniaturization and thinning.

One package that has recently attracted attention is a so-called chip size package (CSP). As the capacity of semiconductor memory chips continues to increase, the chip size is also increasing, but it is becoming increasingly difficult to secure reliability for large-capacity chips using existing package technologies. Therefore, a chip size package that can reduce the size of the package to the level of the chip size and maintain the characteristics of the bare chip in the package state has been in the spotlight recently.

There are many types of chip-size packages, and unique types are developed and introduced one after another according to each manufacturer. A representative type of chip size package is a fine pitch ball grid array (FP-BGA) along with a wafer level chip size package (WL-CSP). For example, Micro BGA, first introduced by Tessera in the United States, is a type of FP-BGA.

Fine pitch ball grid arrays generally use tape wiring boards in which beam leads are formed. The semiconductor chip is bonded to an elastomer attached to one side of the tape wiring board and electrically connected to the beam lead. The connection portion between the beam lead and the chip is protected by a sealing resin, and the terminal for external connection of the package such as a solder ball is formed on the opposite side of the tape wiring board.

However, this structure is vulnerable in terms of reliability. As is well known, semiconductor packages undergo several reliability checks after they have been manufactured, for example, temperature cycling and moisture resistance tests. The temperature cycle test (TC) is a test to check the reliability of a package by periodically changing the temperature from -55 ° C to 125 ° C. The moisture resistance test or the pressure cooker test (PCT) is a test for evaluating the moisture resistance of a package and is performed at 121 ± 2 ° C., 100% humidity, and 2 atmospheres.

The reliability checks provide a fairly harsh environment for the package. Therefore, various defects may occur in the package during the inspection, one of which is the delamination between the beam lead and the sealing resin. The interfacial separation between the two due to the decrease in adhesion between the beam lead and the sealing resin provides a path for moisture to penetrate into the package from the outside. In addition, moisture introduced into the package may cause serious defects such as chip pad corrosion.

Accordingly, an object of the present invention is to improve the reliability of a semiconductor package by blocking a path through which moisture can penetrate into the package from the outside.

1 is a cross-sectional view of a semiconductor package according to an embodiment of the present invention.

FIG. 2 is an enlarged detailed view of a portion of FIG. 1. FIG.

3 to 8 are views illustrating a method of manufacturing a semiconductor package according to an embodiment of the present invention.

9 is a cross-sectional view of a semiconductor package in accordance with another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: semiconductor package

11: semiconductor chip 12: chip pad

13: base film 14: beam lead

15: tape substrate 16: solder ball

17: elastomer 18: encapsulant

20: cover film 21: delamination

30: support frame

31: adhesive tape 32: bonding tool

33: dispenser 34: cutter

In order to achieve the above object, the present invention provides a tape wiring board including beam leads formed in a predetermined pattern on a base film, a semiconductor chip including chip pads to which the respective beam leads are bonded, the semiconductor chip and the An elastic polymer interposed between the tape wiring board, a sealing resin protecting the junction between the beam lead and the chip pad, and solder balls formed on the tape wiring board and electrically connected to the respective beam leads. Provided is a semiconductor package characterized in that a cover film is attached on the sealing resin and the base film to block the inflow of moisture from the.

In addition, the present invention provides a method of manufacturing a tape wiring board on which a beam lead is formed in a predetermined pattern and an elastomer is formed on a base film, and bonding a semiconductor chip on which chip pads are formed to the elastomer; Bonding the beam leads to the chip pads, and attaching a cover film over the base film; Applying a sealing resin to a junction of the beam lead and the chip pad; And forming solder balls on the tape wiring board to be electrically connected to the beam leads.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. Like numbers refer to like elements throughout.

1 is a cross-sectional view of a semiconductor package 10 according to an embodiment of the present invention. Referring to FIG. 1, a plurality of chip pads 12 serving as input / output terminals of an integrated circuit (not shown) formed inside the chip are formed on an upper surface of the semiconductor chip 11. The chip pads 12 are bonded to the beam leads 14 formed on the tape wiring board 15, respectively, and solder balls 16 are formed on opposite sides of the beam leads 14. Thus, a path for transmitting an electrical signal between the semiconductor chip 11 and an external electronic device (not shown) is secured through the chip pad 12, the beam lead 14, and the solder ball 16. An elastomer 17 such as a silicone resin is interposed between the tape wiring board 15 and the semiconductor chip 11.

In the tape wiring board 15, the beam lead 14 is formed on the base film 13 in a predetermined pattern. The base film 13 is made of polyimide, for example, and the beam lead 14 is a copper wiring. Only the gold-plated beam lead 14 without the base film is exposed on the tape wiring board on the chip pad 12 side. Accordingly, the beam lead 14 may be physically bonded to the chip pad 12 by a compressive force applied from the outside. The sealing resin 18 is filled in the junction between the beam lead 14 and the chip pad 12, and the sealing resin 18 is also formed in the outer portion of the package 10.

A feature of the present invention is a cover film 20 attached to the sealing resin 18 on the beam lead 14 side and a portion of the base film 13. As shown in detail in FIG. 2, the interfacial separation 21 phenomenon often occurs in a poor environment, such as a reliability test, between the beam lead 14 and the sealing resin 18. When the interface peeling 21 is generated in this way, moisture easily enters into the package through this. In particular, the moisture penetration is further accelerated when the package is placed under high pressure (2 atmospheres) as in the moisture resistance test described above.

However, when the cover film 20 is attached, the cover film 20 blocks the water penetration path, so even if the interface peeling 21 exists between the beam lead 14 and the sealing resin 18, Can prevent moisture penetration. The cover film 20 may use a self adhesive force or may use a separate adhesive. The material of the cover film 20 is preferably polyimide, and when an adhesive is used, a general epoxy-based adhesive may be used.

Next, a method of manufacturing a semiconductor package according to an embodiment of the present invention will be described with reference to FIGS. 3 to 8. According to this embodiment, several semiconductor packages are simultaneously manufactured on one tape wiring board. Therefore, as shown in FIG. 3, a tape wiring board 15 having a size capable of manufacturing several packages is used, and the tape wiring board 15 is attached onto the fixing frame 30, and the adhesive tape 31 is used. To be fixed. The tape wiring board 15 is composed of the base film 13 and the beam lead 14 described above, and the elastomer 17 is supplied with the tape wiring board 15 attached in advance.

The semiconductor chip 11 separated from the wafer (not shown) is bonded to the elastomer 17 (see FIG. 4). For reference, FIG. 4 is a partial cutaway perspective view of one chip 11 for clarity, and FIGS. 5, 6, and 7 are views corresponding to FIG. 4. 4, 5, and 6 illustrate a state in which the chip 11 is located below, while FIG. 7 illustrates a state in which the chip 11 is located above. As shown in FIG. 4, the chip pads 12 are exposed between the elastomers 17 and correspondingly beam beams 14 are formed. In addition, a portion of the base film 13 is removed in a predetermined region of the tape wiring board 15 so that solder balls may be formed later.

When the bonding of the chip 11 and the elastomer 17 is completed, as shown in FIG. 5, the beam lead 14 is pressed by the presser 32 to be bonded to the chip pad 12, and as shown in FIG. 6. The cover film 20 is attached together. The cover film 20 is adhered to the base film 13, and polyimide, which is the same material as the base film 13, is mainly used. An epoxy-based adhesive may be used to attach the cover film 20.

After attaching the cover film 20, the sealing resin 18 is supplied to protect the beam lead 14 and the chip pad 12 joint as shown in FIG. 7. The sealing resin 18 is a liquid polymer having a predetermined viscosity and is supplied through the applicator 33. The space between the elastomers 17 where the beam lead 14 junctions are formed is actually a very narrow gap. Therefore, when the sealing resin 18 is dropped at the inlet of the gap and left for a predetermined time, the sealing resin 18 flows between the gaps by capillary action to fill all the beam lead joints. At this time, the cover film 20 serves to prevent the sealing resin 18 from flowing down. Vacuum processes may be added to shorten the time that the sealing resin 18 is fully filled and to remove air remaining in the sealing resin, and in most cases, the elastomer 17 and the chip (not just the beam lead 14 junction) 11) Apply the sealing resin 18 to the outside.

After hardening the sealing resin 18, a conventional marking step of printing a product name or the like on the back of the chip is continued (not shown), and then forming the solder balls 16, and then using the cutter 34 The tape wiring board 15 is separated in units of packages 10 (see FIG. 8). Solder ball 16 formation includes detailed processes such as flux application, solder ball attachment, reflow, and the like according to conventional methods. Balls or bumps may be formed of other metals in addition to solder, and paste printing using a mask may be possible.

Unlike the embodiment described above, the cover film may have a size corresponding to the tape wiring board. In this case, like the tape wiring board, the through film should be formed in the cover film so that the place where the solder ball will be formed is exposed to the outside. When the tape wiring board is separated by the package, the cover film is also removed.

The semiconductor package of the present invention may have a structure as in the following embodiment. Referring to FIG. 9, the chip pads 12 of the semiconductor chip 11 are formed at the edge side of the chip, not at the center of the chip. Thus, the elastomer 17 also does not need to be separated into two, unlike the embodiment described above. The pattern structure of the beam lead 14 of the tape wiring board 15 as well as the elastomer 17 is determined according to the arrangement of the chip pads 12. In addition, a sealing resin 18 for protecting the beam lead 14 joint is also formed only at the outside of the package 10. Therefore, the cover film 20 is attached on the sealing resin 18 and the base film 13 toward the outer edge of the package. As described above, the package structure of the present embodiment is somewhat different from that of the above-described embodiment, but the basic configuration is the same, and the manufacturing method thereof is also as described above.

The present invention can significantly improve the reliability of the package because it blocks the path of moisture penetration into the package using the cover film. Moisture introduced into the package along the interface between the beam lead and the sealing resin may corrode the chip pad, thereby lowering the electrical conductivity or, in severe cases, causing the beam lead to fall off the chip pad. In addition, moisture present at the interface between the beam lead and the sealing resin may cause cracking of the sealing resin. As such, various reliability defects that may occur due to moisture can be effectively prevented by the use of the cover film.

In the present specification and drawings, two preferred embodiments of the present invention have been disclosed, and although specific terms are used, these are merely used in a general sense to easily explain the technical content of the present invention and to help the readers understand the present invention. It is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

Claims (3)

A tape wiring board including beam leads formed in a predetermined pattern on a base film, a semiconductor chip including chip pads to which each beam lead is bonded, an elastomer interposed between the semiconductor chip and the tape wiring board, And a sealing resin protecting the junction between the beam lead and the chip pad, and solder balls formed on the tape wiring board and electrically connected to the respective beam leads, to prevent the inflow of moisture from the outside. And a cover film is attached on the sealing resin and the base film. Preparing a tape wiring board having beam leads formed in a predetermined pattern on the base film and having an elastomer formed thereon; and bonding a semiconductor chip having chip pads formed thereon to the elastomer; Bonding the beam leads to the chip pads, and attaching a cover film over the base film; Applying a sealing resin to a junction of the beam lead and the chip pad; Forming solder balls on the tape wiring board to be electrically connected to the beam leads. The method of claim 2, wherein the preparing of the tape wiring board comprises attaching a tape wiring board having a size for simultaneously manufacturing a plurality of semiconductor packages to a fixing frame, and after the forming of the solder ball, the tape wiring The method of manufacturing a semiconductor package further comprising the step of separating the substrate into individual package units.