Semiconductor package having flash-free contacts and techniques for manufacturing the same

Abstract

Techniques for forming packaged semiconductor devices having top surfaces with flash-free electrical contact surfaces are described. According to one aspect, a molding cavity is provided which has a molding surface that is sufficiently smooth such that when placed in contact with an electrically conductive contact, gaps between the conductive contact and the mold cavity surface do not form.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This is a Divisional application of co-pending prior U.S. application Ser. No. 10 / 274,056 (Atty. Dkt. No. NSC1P245 / P05326), entitled “TECHINIQUES FOR MANUFACTURING FLASH-FREE CONTACTS ON A SEMICONDUCTOR PACKAGE”, filed on Oct. 17, 2002, which is incorporated herein by reference and from which priority under 35 U.S.C. § 120 is claimed. [0002] This application is related to U.S. Pat. No. 6,364,542, filed May, 9, 2000, entitled “Device and Method for Providing a True Semiconductor to External Fiber Optic Cable Connection,” to U.S. patent application Ser. No. 09 / 922,598 (Attorney Docket No. NSC1P205), filed Jul. 11, 2001, entitled “Techniques for Joining an Optoelectronic Module to a Semiconductor Package”, to U.S. patent application Ser. No. 09 / 822,601 (Attorney Docket No. NSC1P212), filed Aug. 14, 2001, entitled “Optical Sub-Assembly for Opto-Electronic Modules”, to U.S. patent application Ser. No. 09 / 963,039 (Attorney Docket No. NSC1P215...

AI Technical Summary

Benefits of technology

The present invention is about a device that makes flash-free electrical contacts on the top of semiconductor packages without needing extra equipment or steps after injection molding. The device has a smooth inside surface that allows for better contact between the molding cavity and the electrical contacts, preventing molding material from flowing between them. This results in flash-free electrical contacts after the molding process. The device includes a molding chamber with a top molding cavity and a bottom molding cavity to support the semiconductor die. The method involves placing the semiconductor device with electrical connectors on its top surface in the molding chamber, lowering the top molding cavity onto the device, and injecting molding compound into the molding cavity to prevent flash formation on the top surfaces of the electrical connectors.

Problems solved by technology

The typical mold cavity does not form a perfect seal with the surfaces and edges of the device enclosed by the cavity.

Wherever gaps exist between the mold cavity and the device, there is a potential for resin material to be deposited in unwanted areas.

When flash forms on electrical contact leads, for instance, post-plating operations cannot proceed since metal cannot be deposited on the insulating layer.

This occurs because a standard mold chamber has surfaces that are not completely smooth.

Unfortunately, conventional means of removing flash are not desirable since they are slow and require additional equipment.

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