Texas Instruments Corporation

Richard L Mahle

Peter J Sakakini

Randall V Tekavec

John Walter Orcutt

Henry L Humphrey

A method for treating an area of a semiconductor wafer surface with a laser for reducing stress concentrations is disclosed. The wafer treatment method discloses treating an area of a wafer surface with a laser beam, wherein the treated area is ablated or melted by the beam and re-solidifies into a more planar profile, thereby reducing areas of stress concentration and stress risers that contribute to cracking and chipping during wafer singulation. Preferably, the treated area has a width less than that of a scribe street, but wider than the kerf created by a wafer dicing blade. Consequently, when the wafer is singulated, the dicing blade will preferably saw through treated areas only. It will be understood that the method of the preferred embodiments may be used to treat other areas of stress concentration and surface discontinuities on the wafer, as desired.

Method for reducing stress concentrations on a semiconductor wafer by surface laser treatment

Disclosed is a method of making a mold lock for bonding leadframe-to-plastic in an IC package. Steps include providing niches from opposing sides of the leadframe. The opposing niches are arranged such that an aperture and a mechanical key are formed within the leadframe material by the partial intersection of the niches. The key is encapsulated with mold compound to form a lock. An IC package mold lock in a leadframe is also disclosed, the lock having an aperture, a key, and mold compound encapsulating the key. Additionally, an IC package employing the leadframe-to-plastic lock is disclosed.

Leadframe-to-plastic lock for IC package

Method for reducing stress concentrations on a semiconductor wafer by surface laser treatment including the backside

A method of making a ball grid array package wherein there is provided a partially fabricated package including a semiconductor die, leads and balls secured to predetermined ones of the leads. The leads and balls are concurrently coated with palladium. The die, leads and at least a portion of each of the balls are then encapsulated. Encapsulation includes providing a mold including a plurality of recesses, each recesses for receiving one of the balls. A plurality of cavities is provided in the package, each extending to one of the leads at the location of one of the balls. A plurality of mold members is provided, each extendable into one of the cavities to apply a force against the ball associated with the lead to which the cavity extends. The partially fabricated package is placed into the mold so that the balls extend into the recesses and the mold members extends into the cavities. The molding material is applied to the mold cavity to provide the encapsulation.

Lead frame type plastic ball grid array package with pre-assembled ball type contacts

A wire bond station has a platform (32) in cavity (31) of the work station heater block (30) on which a lead frame die mount pad (33) is placed during wire bonding to semiconductor chip mounted on the die mount pad. The platform (32) is of a dimension such that the edges of the die mount pad (33) extend out from the platform (32) so that irregularities (34) on the edges of the die mount pad (33) do not support the die mount pad (33) above the platform (32).

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McKinney, TX, United States of America

Richard L Mahle