US 6,306,682 B1Granted

Method of fabricating a ball grid array integrated circuit package having an encapsulating body

AssigneeSiliconware Precision Industries Co., Ltd.

InventorsChien-Ping Huang, Randy H. Y. Lo, Tzong-Da Ho, Eric Ko, Jui-Meng Jao

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Abstract

A method of fabricating a BGA (Ball Grid Array) IC package of the type having an encapsulating body is proposed, which allows the BGA IC package to be manufactured without having to use conventional organic substrate and encapsulating-body mold having cavity, so that the manufacture process can be more cost-effective to carry out than the prior art. The proposed method is characterized in the use of a copper piece which is selectively removed to form an encapsulating-body cavity for the forming of an encapsulating body therein. The proposed method requires no use of mold with cavity for the forming of the encapsulating body, allowing the same mold to be used for the fabrication of various BGA IC packages of different sizes. Moreover, the proposed method allows fan-in design as well as fan-out design, thus allowing the number of I/O ports to be increased while making the overall package configuration compact in size, and also allows the implantation of the electrically-conductive balls to be easier to carry out and more precisely controlled than the prior art, making the ball implantation more assured in quality than the prior art. Therefore, the proposed method is more advantageous and cost-effective to use than the prior art.

Claims14

Dependent claims

A method for fabricating a BGA IC package, comprising the steps of:

(1) preparing a copper piece having a first surface coated with a first photoresist layer and a second surface coated with a second photoresist layer,
(2) performing a selective-removal process on the second photoresist layer;
(3) coating an electrically-conductive material over those areas over the second surface of the copper piece that are unmasked by the remaining part of the second photoresist layer to thereby form an electrically-conductive trace structure;
(4) removing all the remaining parts of the first and second photoresist layers;
(5) coating a first solder mask over the first surface of the copper piece and a second solder mask over the second surface of the copper piece;
(6) defining a plurality of solder-ball openings in the second solder mask and an encapsulating-body opening in the first solder mask,
(7) with the first solder mask serving as mask, removing the unmasked part of the copper piece through the encapsulating-body opening until reaching the electrically-conductive trace structure on the opposite side of the copper piece to thereby form an encapsulating-body cavity in the copper piece;
(8) mounting at least one IC chip within the encapsulating-body cavity and over the electrically-conductive trace structure and the second solder mask;
(9) electrically coupling the IC chip to corresponding points on the electrically-conductive trace structure;
(10) forming an encapsulating body in the combined hollow space of the encapsulating-body cavity and the encapsulating-body opening;
(11) implanting a plurality of electrically-conductive balls in the solder-ball openings;
and
(12) cutting away the remaining parts of the copper piece.

10 more elements

Dependencies are inferred from the claim text.