Advanced Micro Devices Corporation

Mathias Boettcher

Frank G Kuechenmeister

Dennis J Herrell

Gisela Schammler

A solder bump structure and a method for forming the same are disclosed. Over a contact pad a first and a second metal film are deposited, wherein the second metal film is patterned prior to the deposition of a solder bump material such that an opening isolates an inner region of the second metal film from an outer region of the second metal film. The solder material deposited on the inner region and, at least partially, in the opening serves as an etch stop for a subsequent removal of the outer region.

Solder bump structure and a method of forming the same

A plurality of uniform bumps are formed on a semiconductor device by forming a mask onto the surface of the semiconductor device with openings in the mask that correspond to the electrical contact pads on the surface of the semiconductor device. Solder or other conductive material is deposited on the pads. A rate of solder or other conductive material deposition which may not give a uniform thickness of solder or other conductive material across the surface of the wafer may be used. Solder or other conductive material is deposited until each opening in the mask is filled with solder or other conductive material. Next, the mask and solder or other conductive material balls formed are scrubbed until the mask and the soldier balls reach a substantially uniform height. The openings formed in the mask have substantially the same footprint or area associated with each pad. Since the solder or other conductive material balls are at the same height, the solder or other conductive material balls have approximately the same volume. The next step is to remove the mask and plating base metallization using a wet or dry etching process. If the material is solder, the next step is to reflow the solder to form substantially uniform solder balls or bumps on each pad across the wafer. The wafer is then diced to form individual chips having bumps which are uniform in height and volume.

Bump scrub after plating

A decoupling capacitor structure formed integral with an integrated circuit chip and over top of circuitry defined thereon advantageously provides decoupling capacitance in close electrical proximity to switching circuits of the integrated circuit chip without substantially affecting die footprint. In contrast with on-die gate oxide capacitor configurations, a decoupling capacitor structure formed toward the back end of processing, typically after interconnect metal, allows large area capacitor structures without substantial impact on area available for devices and circuitry. Inductance associated with the intervening portion of a power supply loop circuit between switching circuits of the integrated circuit chip and the decoupling capacitor structure can be extremely low in configurations in accordance with the present invention. In some configurations, connection points, e.g., bonding pads and/or solder bumps for conveying power supply voltages, are defined over top of the decoupling capacitor structure.

Decoupling capacitor configuration for integrated circuit chip

A plurality of uniform bumps are formed on a semiconductor device by forming a plurality of bond limiting metallization areas. The surface of the semiconductor device is then plated with a plating metal that will be alloyed with the solder of the solder bump, said solder and the plating material forming an alloy during the reflowing step. A mask is then placed onto the surface of the semiconductor device. Openings are made in the mask that correspond to the plurality of bond limiting metallization areas on the surface of the semiconductor device. The plurality of bond limiting metallization areas are also the electrical contact pads. Solder is then deposited through the openings in the mask at a rate of solder deposition which provides a uniform thickness of solder across the surface of the wafer which is later diced into many chips. The openings formed in the mask have substantially a bigger footprint or area associated with each pad. Since the solder balls are at the same height, the solder balls have approximately the same volume. Next, the mask and plating layer beneath the mask are removed leaving a substantially uniform volume of solder and plating material positioned on and near the plurality of bond limiting metallization areas. The next step is to reflow the solder to form substantially uniform solder balls or bumps on each pad across the wafer by consuming the plating metal. The plating material beneath the solder alloys with the solder during this step. In addition, the solder and plating material gathers on each bond limiting metallization area to form bumps which are uniform in height and volume.

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Dresden, Germany

Mathias Boettcher