Patent ID: 6341418
Filing Date: 2002-01-29
Classification: H01L,Y10T

Abstract:
A method for bonding a semiconductor chip formed of a semi-conducting material to a circuit board by solder bumps and an underfill layer comprising the steps of:providing a semiconductor chip having a top surface formed with a first multiplicity of conductive pads, coating a layer of insulating material with a multiplicity of apertures on said top surface of the semiconductor chip exposing said first multiplicity of conductive pads, said layer of insulating material having a thickness substantially similar to a thickness of said solder bumps to be deposited, depositing a ball-limiting-metallurgy (BLM) layer in said first multiplicity of apertures overlying said first multiplicity of conductive pads, filling said first multiplicity of apertures with a solder material forming a first multiplicity of solder bumps, providing a circuit board having a second multiplicity of conductive pads formed on a top surface positioned in mirror image to said first multiplicity of conductive pads on said semiconductor chip, dispensing a layer of an underfill material on said top surface of the circuit board, and engaging said top surface of the circuit board and said top surface of the semiconductor chip together with said first multiplicity of conductive pads intimately contacting said second multiplicity of conductive pads through said layer of underfill material and heating to a temperature sufficient to establish electrical communication between said first multiplicity and said second multiplicity of conductive pads, and bonding said semiconductor chip to said circuit board by said layer of insulating material having a CTE between that of said solder material and said semi-conducting material.