Methods and systems for laser assisted wirebonding

Abstract

The invention provides methods and systems for laser assisted wirebonding. One or more conditioning laser pulses are used to prepare a bonding surface for wirebonding by removing impurities such as residues from manufacturing processes, oxides, or irregularities on the bonding surface. Subsequently, a free air ball is brought into contact with the conditioned bonding surface to form a weld.

1 . In a manufacturing process for a microelectronic semiconductor device having a bonding surface and a bondwire, a method of wirebonding comprising:
 conditioning the bonding surface with an application of at least one first laser pulse;   forming a free air ball on the bondwire for welding;   applying at least one second laser pulse to the bonding surface to heat the bonding surface; and   coordinating one or more control signals to control the second laser pulse and the free air ball such that a temperature of the bonding surface and the free air ball are suitable for forming a weld joining the bondwire with the bonding surface.   
     
     
         2 . A method according to  claim 1  wherein the at least one first laser pulse consists of light having a wavelength of about 1064 nanometers. 
     
     
         3 . A method according to  claim 1  wherein the at least one first laser pulse has a fluence within a range of about one micro-Joule to about one Joule per square centimeter. 
     
     
         4 . A method according to  claim 1  wherein the at least one first laser pulse has a duration of about one to one hundred nanoseconds. 
     
     
         5 . A method according to  claim 1  wherein the at least one first laser pulse comprises a plurality of laser pulses having a repetition rate of about 1-10,000 Hertz. 
     
     
         6 . A method according to  claim 1  wherein the bondwire comprises gold. 
     
     
         7 . A method according to  claim 1  wherein the bondwire comprises copper. 
     
     
         8 . A method according to  claim 1  wherein the bondwire comprises aluminum. 
     
     
         9 . A method according to  claim 1  wherein the bondwire comprises silver. 
     
     
         10 . A method according to  claim 1  wherein the bondwire comprises palladium. 
     
     
         11 . A method according to  claim 1  wherein the bonding surface comprises aluminum. 
     
     
         12 . A method according to  claim 1  wherein the bonding surface comprises copper. 
     
     
         13 . A method according to  claim 1  wherein the weld is formed without applying additional heat from below the bonding surface. 
     
     
         14 . A method according to  claim 1  wherein the weld is formed without applying ultrasonic energy to the bonding surface. 
     
     
         15 . A method according to  claim 1  wherein the bonding surface is a multilayer bond pad comprising a layer chosen from a low-K layer or an ultra-low-K layer.