Infineon Technologies Ag

National Semiconductor Corporation

Lim Fong

Jaime A Bayan

Alexander Heinrich

Manfred Mengel

Edmund Riedl

Evelyn Napetschnig

Nghia Thuc Tu

Thomas Behrens

Chan Peng Yeen

Oliver Eichinger

Steffen Orso

A chip arrangement including a chip comprising a chip back side; a back side metallization on the chip back side, the back side metallization including a plurality of layers; a substrate comprising a surface with a metal layer; a zinc-based solder alloy configured to attach the back side metallization to the metal layer, the zinc-based solder alloy having by weight 8% to 20% aluminum, 0.5% to 20% magnesium, 0.5% to 20% gallium, and the balance zinc; wherein the metal layer is configured to provide a good wettability of the zinc-based solder alloy on the surface of the substrate. The plurality of layers may include one or more of a contact layer configured to contact a semiconductor material of the chip back side; a barrier layer; a solder reaction, and an oxidation protection layer configured to prevent oxidation of the solder reaction layer.

Chip arrangements

A solder alloy is providing, the solder alloy including zinc, aluminum, magnesium and gallium, wherein the aluminum constitutes by weight 8% to 20% of the alloy, the magnesium constitutes by weight 0.5% to 20% of the alloy and the gallium constitutes by weight 0.5% to 20% of the alloy, the rest of the alloy including zinc.

Solder alloys and arrangements

In one aspect of the invention, a method of attaching a semiconductor die to a microarray leadframe is described. The method comprises stamping an adhesive onto discrete areas of the microarray leadframe using a multi-pronged stamp tool. The adhesive is applied to the leadframe as a series of dots, each dot corresponding to an associated prong of the stamping tool. In some embodiments the adhesive used to attach the semiconductor die to a leadframe is a black epoxy based adhesive material. In an apparatus aspect of the invention, lead traces in a microarray leadframe are arranged to have tails that extend beyond their associated contact posts on the side of the contact post that is opposite a wire bonding region such that such lead traces extends on two opposing sides of their associated contact posts. The tails do not attach to other structures within the lead frame (such as a die attach structure). The width of at least some of these tailed lead traces in a region that overlies their associated contact post is narrower than their associated contact post. Thus, these narrowed lead traces have extensions that extend beyond their associated contact posts. The extensions provide additional surface area that gives an adhesive applied to the narrowed lead trace (as for example by stamping) room to bleed (flow) along the top surface of the lead trace on both sides of the associated contact pad.

Die attach method and leadframe structure

Die attach method and microarray leadframe structure

Growing community of inventors

Melaka, Malaysia

Lim Fong