A semiconductor wafer has a plurality of semiconductor die with contact pads for electrical interconnect. An insulating layer is formed over the semiconductor wafer. A bump structure is formed over the contact pads. The bump structure has a buffer layer formed over the insulating layer and contact pad. A portion of the buffer layer is removed to expose the contact pad and an outer portion of the insulating layer. A UBM layer is formed over the buffer layer and contact pad. The UBM layer follows a contour of the buffer layer and contact pad. A ring-shaped conductive pillar is formed over the UBM layer using a patterned photoresist layer filled with electrically conductive material. A conductive barrier layer is formed over the ring-shaped conductive pillar. A bump is formed over the conductive barrier layer. The buffer layer reduces thermal and mechanical stress on the bump and contact pad.

An integrated circuit device may include a multi-material toothed bond pad including (a) an array of vertically-extending teeth formed from a first material, e.g., aluminum, and (b) a fill material, e.g., silver, at least partially filling voids between the array of teeth. The teeth may be formed by depositing and etching aluminum or other suitable material, and the fill material may be deposited over the array of teeth and extending down into the voids between the teeth, and etched to expose top surfaces of the teeth. The array of teeth may collectively define an abrasive structure. The multi-material toothed bond pad may be bonded to another bond pad, e.g., using an ultrasonic or thermosonic bonding process, during which the abrasive teeth may abrade, break, or remove unwanted native oxide layers formed on the respective bond pad surfaces, to thereby create a direct and/or eutectic bonding between the bond pads.

An integrated circuit device may include a multi-material toothed bond pad including (a) an array of vertically-extending teeth formed from a first material, e.g., aluminum, and (b) a fill material, e.g., silver, at least partially filling voids between the array of teeth. The teeth may be formed by depositing and etching aluminum or other suitable material, and the fill material may be deposited over the array of teeth and extending down into the voids between the teeth, and etched to expose top surfaces of the teeth. The array of teeth may collectively define an abrasive structure. The multi-material toothed bond pad may be bonded to another bond pad, e.g., using an ultrasonic or thermosonic bonding process, during which the abrasive teeth may abrade, break, or remove unwanted native oxide layers formed on the respective bond pad surfaces, to thereby create a direct and/or eutectic bonding between the bond pads.

A solder ball includes a silver ball structure and a shell structure. The shell structure wraps a surface of the silver ball structure, and a material of the shell structure at least includes tin. When the solder ball is bonded to other devices, the ball height of the solder ball remains constant to avoid collapse.

A structure comprises a plurality of top pads protruding over a top surface of a package substrate, wherein a top pad comprises a first half-circle portion, a second half-circle portion and a first rectangular portion between the first half-circle portion and the second half-circle portion, a plurality of bottom pads embedded in the package substrate, wherein a bottom pad comprises a third half-circle portion, a fourth half-circle portion and a second rectangular portion between the third half-circle portion and the fourth half-circle portion and a plurality of vias coupled between the top pads and their respective bottom pads.

An integrated circuit structure includes an alignment bump and an active electrical connector. The alignment bump includes a first non-solder metallic bump. The first non-solder metallic bump forms a ring encircling an opening therein. The active electrical connector includes a second non-solder metallic bump. A surface of the first non-solder metallic bump and a surface of the second non-solder metallic bump are substantially coplanar with each other.

Provided are a lead-free solder alloy which consists of Sb in an amount of more than 3.0% but 10% or less by mass, and the balance including Sn, and others.

Methods, techniques, and structures relating to die packaging. In one exemplary implementation, a die package interconnect structure includes a semiconductor substrate and a first conducting layer in contact with the semiconductor substrate. The first conducting layer may include a base layer metal. The base layer metal may include Cu. The exemplary implementation may also include a diffusion barrier in contact with the first conducting layer and a wetting layer on top of the diffusion barrier. A bump layer may reside on top of the wetting layer, in which the bump layer may include Sn, and Sn may be electroplated. The diffusion barrier may be electroless and may be adapted to prevent Cu and Sn from diffusing through the diffusion barrier. Furthermore, the diffusion barrier may be further adapted to suppress a whisker-type formation in the bump layer.

A method of forming a semiconductor package is provided. The method includes forming a metallization stack over a semiconductor die. Polymer particles are mounted over the metallization stack. Each of the polymer particles is coated with a first bonding layer. A heat spreader lid is bonded with the semiconductor die by reflowing the first bonding layer. A composite thermal interface material (TIM) structure is formed between the heat spreader lid and the semiconductor die during the bonding. The composite TIM structure includes the first bonding layer and the polymer particles embedded in the first bonding layer.

A method of forming a semiconductor package is provided. The method includes forming a metallization stack over a semiconductor die. Polymer particles are mounted over the metallization stack. Each of the polymer particles is coated with a first bonding layer. A heat spreader lid is bonded with the semiconductor die by reflowing the first bonding layer. A composite thermal interface material (TIM) structure is formed between the heat spreader lid and the semiconductor die during the bonding. The composite TIM structure includes the first bonding layer and the polymer particles embedded in the first bonding layer.