Continuous mode solder jet apparatus and method

Abstract

A solder jet apparatus and method is disclosed. The solder jet apparatus is a continuous mode solder jet that includes a blanking system and raster scan system. The use of the raster scan and blanking systems allows for a continuous stream of solder to be placed anywhere on the surface in any desired X-Y plane. This allows for greater accuracy as well as greater product throughput. Additionally, with the raster scan system, repairs to existing soldered surfaces can be quickly and easily performed using a map of the defects for directing the solder to the defects.

1 . A liquid metal deposition apparatus comprising: 
 a continuous stream generator for producing a stream of liquid metal solder droplets, the liquid metal solder droplets having a substantially uniform size within a consistent predetermined range, the consistent predetermined range of substantially uniform size metal solder droplets being within a size of a selected bond pad of one a semiconductor die and the contact pads of the substrate; and    a director for selectively directing a stream of liquid metal solder droplets after being produced by the continuous stream generator onto the selected bond pads of the at least one semiconductor die of the substrate, the stream director including a raster scanner for scanning the stream of liquid metal solder droplets, the raster scanner including: 
 an electrical charge generator for charging at least a portion of the liquid metal solder droplets of the stream of liquid metal solder droplets with an electrical charge;  
 a stream blanking device for intermittently blanking at least some of the liquid metal solder droplets of the stream of liquid metal solder droplets; and  
 an electrically charged droplet deflector for deflecting at least one electrically charged liquid metal solder droplet of the stream of liquid metal solder droplets in a first direction and a second direction for deposition at a location of a plurality of locations extending throughout the surface of the substrate while the substrate remains stationary.  
   
   
   
       2 . The apparatus according to  claim 1 , wherein the continuous stream generator comprises: 
 a pressure inducer; and    the vibrator comprises a vibrator connected to the pressure inducer for causing formation of the stream of liquid metal solder droplets in connection with the pressure inducer.    
   
   
       3 . The apparatus according to  claim 2 , wherein the pressure inducer comprises a piezoelectric crystal operating at a desired frequency.  
   
   
       4 . The apparatus according to  claim 2 , wherein the vibrator comprises a piezoelectric crystal operating at a selected frequency to form liquid metal droplets having a size in the range of micron size droplets of a liquid metal solder.  
   
   
       5 . The apparatus according to  claim 1 , wherein the continuous stream generator includes a solder jet nozzle having an aperture producing a consistent range of droplets of the liquid metal solder for forming the stream of liquid metal solder droplets.  
   
   
       6 . The apparatus according to  claim 5 , wherein the continuous stream generator further includes a solenoid connected to the solder jet nozzle.  
   
   
       7 . The apparatus according to  claim 1 , wherein the stream blanking device at least provides blanking of the at least some of the stream of liquid metal solder droplets when the stream of liquid metal solder droplets is positioned between the endpoint of a first location of the plurality of locations extending throughout the surface of the substrate and the start point of a second location of the plurality of locations extending throughout the surface of the substrate.  
   
   
       8 . The apparatus according to  claim 1 , wherein the stream blanking device comprises: 
 a deflector field device selectively deflecting at least one droplet of the stream of liquid metal solder droplets; and    a droplet catcher catching the at least one droplet which has been deflected from the stream of liquid metal solder droplets prior to the at least one droplet which has been deflected from the stream of liquid solder droplets being deposited on at least one bond pad of the at least one semiconductor die of the substrate.    
   
   
       9 . The apparatus according to  claim 1 , wherein the stream director includes a programmable direction controller for determining a direction of the stream of liquid metal solder droplets.  
   
   
       10 . A method for depositing liquid metal comprising: 
 producing a stream of liquid metal solder droplets having a substantially uniform size within a consistent predetermined range, the consistent predetermined range of substantially uniform size metal solder droplets being within a size of a selected bond pad of one a semiconductor die and the contact pads of the substrate; and    directing a stream of liquid metal solder droplets after being produced by the continuous stream generator onto the selected bond pads of the at least one semiconductor die of the substrate, the stream director including a raster scanner for scanning the stream of liquid metal solder droplets, the raster scanner including: 
 an electrical charge generator for charging at least a portion of the liquid metal solder droplets of the stream of liquid metal solder droplets with an electrical charge;  
 a stream blanking device for intermittently blanking at least some of the liquid metal solder droplets of the stream of liquid metal solder droplets; and  
   deflecting at least one electrically charged liquid metal solder droplet of the stream of liquid metal solder droplets in a first direction and a second direction for deposition at a location of a plurality of locations extending throughout the surface of the substrate while the substrate remains stationary using an electrically charged droplet deflector.    
   
   
       11 . The method according to  claim 10 , wherein said producing further comprises: 
 heating a solder metal to a liquid state in the reservoir; and    controlling a temperature of the liquid solder metal in the reservoir for providing said stream of liquid solder metal droplets in said liquid state while selectively directing said stream of liquid solder metal droplets for contacting portions of a substrate located on a stationary support.    
   
   
       12 . The method according to  claim 10 , wherein said producing further comprises: 
 inducing a pressure on a source of liquid metal; and    vibrating said liquid metal to cause said stream of liquid solder metal droplets to be formed as said pressure is induced on said source of liquid metal.    
   
   
       13 . The method according to  claim 12 , wherein said pressure inducing is generated by a first piezoelectric crystal driven by a given frequency to produce a desired pressure.  
   
   
       14 . The method according to  claim 13 , wherein said vibrating is generated by a second piezoelectric crystal driven by a selected frequency to produce a given vibration frequency sufficient enough to form droplets having a diameter in the range of 40 microns to 300 microns.  
   
   
       15 . The method according to  claim 10 , wherein said producing further comprises forming said stream of liquid solder metal droplets having a consistent diameter in the range of 40 microns to 300 microns.  
   
   
       16 . The method according to  claim 10 , wherein said blanking comprises blanking when said stream of liquid solder metal droplets is positioned between an endpoint of a first horizontal scan line and a start point of a second horizontal scan line with respect to a substrate located on a stationary support.  
   
   
       17 . The method according to  claim 10 , wherein said blanking further comprises: 
 deflecting said stream of liquid solder metal droplets; and    catching said deflected stream of liquid solder metal droplets to prevent said drops from being deposited on said substrate located on a stationary support.    
   
   
       18 . The method according to  claim 10 , wherein said directing comprises 
 programmably controlling a direction of said stream of liquid solder metal droplets for deposition on portions of a substrate located on a stationary support.    
   
   
       19 . The method of  claim 10 , wherein the directing said stream of liquid solder metal droplets in a first dimension and a second dimension, such that solder is deposited at said locations on a substrate maintained in a stationary portion located on said stationary support, said directing comprising: 
 raster scanning said stream of liquid solder metal droplets, said raster scanning including electrically charging said stream of liquid solder metal droplets;    electrostatically deflecting said electrically charged stream of liquid solder metal droplets in a first variable electrostatic potential in said first dimension for contacting portions of a substrate located on a stationary support;    electrostatically deflecting said electrically charged stream of liquid metal droplets in a second variable electrostatic potential in said second dimension to said locations on said substrate located on a stationary support; and    blanking selectively said stream of liquid solder metal droplets to prevent a portion of said stream of liquid solder metal droplets from contacting said substrate located on a stationary support.