Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor
Reexamination Certificate
2000-06-13
2001-09-18
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
C438S051000
Reexamination Certificate
active
06291263
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to integrated circuit packaging technology, and more particularly, to a method of fabricating an integrated circuit package of the type having a core-hollowed encapsulation body for housing an optically-sensitive semiconductor chip.
2. Description of Related Art
Semiconductor device packaging technology is used to pack one or more semiconductor chips in a single module that can be easily handled and mounted onto printed circuit boards. Typically, the semiconductor chip or chips are enclosed inside an opaque compound (or called encapsulation body), and is thus invisible from the outside. However, for optically-sensitive types of semiconductor chips, such as image-sensor chips or ultraviolet-sensitive EP-ROM (Electrically-Programmable Read-Only Memory) chips, it is required to allow these chips to sense ambient light. For this reason, a special package configuration is used to pack these types of semiconductor chips. One conventional package configuration to pack an optically-sensitive semiconductor chip is to mount it inside an encapsulation body having a core-hollowed portion; and then, after performing wire bonding to the chip, hermetically seal an transparent lid over the opening of the core-hollowed portion of the encapsulation body. Ambient light can then pass through the transparent lid to the inside of the encapsulation body to be sensed by the chip enclosed therein.
One drawback to the forgoing package configuration, however, is that, during the molding of the core-hollowed encapsulation body, resin flash on lead frame is a serious problem, which would undesirably degrade the quality of the die attachment and wire bonding on the flashed parts of the lead frame. To solve this problem, various solutions have been proposed, including, for example, the U.S. Pat. No. 5,070,041 entitled “METHOD OF REMOVING FLASH FROM A SEMICONDUCTOR LEADFRAME USING COATED LEADFRAME AND SOLVENT” issued on Dec. 3, 1991, which can remove resin flash built up on lead frame without damaging resin molded section. This patented method is characterized in the steps of coating an organic high-molecule substance over the areas of the lead frame that are to be uncovered by the encapsulation body; and then, after the encapsulation body is completely formed, using a special solvent to wash away the organic high-molecule coating, whereby the resin flash can be removed together with the organic high-molecule coating. After this, a semiconductor chip is mounted onto the flash-free die pad, and then a transparent lid is hermetically sealed to the opening of the core-hollowed portion of the encapsulation body.
The forgoing patented method, however, has the following drawbacks. Firstly, the step of coating organic high-molecule substance and the subsequent step of dissolving the coating to remove resin flash are quite complex in procedure and costly to implement, making the overall fabrication process quite cost-ineffective. Secondly, the solvent can be corrosive to the lead frame, which would also undesirable degrade the quality of the die attachment and wire bonding on the lead frame. Third, the solvent, after being used, would cause pollution and thus is environmentally-unfriendly to use.
SUMMARY OF THE INVENTION
It is therefore an objective of this invention to provide a new method for fabricating a semiconductor device package of the type having a core-hollowed encapsulation body, which can help prevent resin flash on lead frame during the molding of the core-hollowed encapsulation body.
It is another objective of this invention to provide a new s method for fabricating a semiconductor device package of the type having a core-hollowed encapsulation body, which can help prevent resin flash on lead frame without having to use expensive coating process and environmentally-pollutant solvent.
It is still another objective of this invention to provide a new method for fabricating a semiconductor device package of the type having a core-hollowed encapsulation body, which can help prevent resin flash on lead frame in a more cost-effective and quality-assured way than the prior art.
It is still another objective of this invention to provide a new method for fabricating a semiconductor device package of the type having a core-hollowed encapsulation body, which allows the fabricated package to be more reliable to use than the prior art.
In accordance with the foregoing and other objectives, the invention proposes a new method for fabricating a semiconductor device package of the type having a core-hollowed encapsulation body.
The method of the invention comprises the following procedural steps: preparing a leadframe including a die-bonding area and a wire-bonding area and having a front side and a back side; attaching a tape of a specific size onto the front side of the leadframe to cover the entire die-bonding area and the wire-bonding area; performing a molding process by fixing the leadframe in an encapsulation mold and filling an encapsulation material into all the void portions in the encapsulation mold to thereby form an encapsulation body having a core-hollowed portion; removing the tape to expose the die-bonding area and the wire-bonding area; attaching a semiconductor chip onto the die-bonding area; connecting a set of bonding wires for electrically coupling the semiconductor die to the wire-bonding area of the leadframe; and covering a lid on the opening of the core-hollowed portion of the encapsulation body.
It is a characteristic feature of the invention that, since the entire die-bonding area and the wire-bonding area are covered by the tape during the molding of the encapsulation body, the entire die-bonding area and the wire-bonding area would be prevented from resin flash. Therefore, after the tape is removed, these areas would be substantially free of resin flash. Since the removal of the tape is very easy to carry out and would cause no pollution as compared to the use of solvent for post treatment by the prior art, the invention is more advantageous to use than the prior art.
REFERENCES:
patent: 5070041 (1991-12-01), Katayama et al.
patent: 5482898 (1996-01-01), Marrs
patent: 5563443 (1996-10-01), Beng et al.
patent: 5650593 (1997-07-01), Mc Millan et al.
Corless Peter F.
Edwards & Angell LLP
Nelms David
Nhu David
Siliconware Precision Industries Co., LTD.
LandOfFree
Method of fabricating an integrated circuit package having a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of fabricating an integrated circuit package having a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of fabricating an integrated circuit package having a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2516275