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Pre-bend Leadframe Bonding Methodology

IP.com Disclosure Number: IPCOM000031286D
Published in the IP.com Journal: Volume 4 Issue 10 (2004-10-25)
Included in the Prior Art Database: 2004-Oct-25

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

Prior art of manufacturing of discrete semiconductors involves and needs a base leadframe, a die attached process, a wire bonding process, a molding process, a trim and form process and then testing. The leadframe is being unreeled and then proceeded to die bonder machine. The bonding machine picks up a die from the wafer and die-attaches to the leadframe. The wire bonding machine bond gold wire from the die pad to the leadframe designated area. The gold wire is being used for this wire bonding processes to form an electrical connection from the die bond pad to the leadframe. Forming processes have the tendency to add stresses onto the unit causing delamination. Wire bonding have the potential capability of creating sagging wire that will end up as a malfunction unit at customer field usage. A new method of wire bonding replaces the gold wire with the leadframe as an electrical connectivity element. A stamped and pre-formed leadframe is being reeled onto a base leadframe where the dies are mounted onto it. Then, the pre-formed leadframe is being unreeled and precisely aligned by a guidance system and then lands on top of the bond pads of the dies. After that, the base leadframe and the top leadframe is heated to allow for bonding of the dies with solder bump to the leadframe.

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Pre-bend Leadframe Bonding Methodology

Idea: Keong Bun Hin, MY-Melaka; Goh Koh Hoo, MY-Melaka

Prior art of manufacturing of discrete semiconductors involves and needs a base leadframe, a die attached process, a wire bonding process, a molding process, a trim and form process and then testing. The leadframe is being unreeled and then proceeded to die bonder machine. The bonding machine picks up a die from the wafer and die-attaches to the leadframe. The wire bonding machine bond gold wire from the die pad to the leadframe designated area. The gold wire is being used for this wire bonding processes to form an electrical connection from the die bond pad to the leadframe. Forming processes have the tendency to add stresses onto the unit causing delamination. Wire bonding have the potential capability of creating sagging wire that will end up as a malfunction unit at customer field usage.

A new method of wire bonding replaces the gold wire with the leadframe as an electrical connectivity element. A stamped and pre-formed leadframe is being reeled onto a base leadframe where the dies are mounted onto it. Then, the pre-formed leadframe is being unreeled and precisely aligned by a guidance system and then lands on top of the bond pads of the dies. After that, the base leadframe and the top leadframe is heated to allow for bonding of the dies with solder bump to the leadframe.

The new idea can offer a substantial advantage of reducing the cost structure of manufacturing semiconductor by eliminating the need of using gold during wire bonding. There is no need to do wire bonding, as the pre-bend leadframe itself is placed onto of the die whereby acting like a wire to do the required electrical connection directly to the leadpad. By means of p...