Method for generating continuous stream of liquid metal droplets

• US 6,350,494 B1
• Filed: 06/23/1999
• Issued: 02/26/2002
• Est. Priority Date: 12/12/1997
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Farnworth, Warren M.
• Primary Examiner(s): Beck, Shrive P.
• Assistant Examiner(s): CALCAGNI, JENNIFER A
• Application Number:
  US09/339,015
• Time in Patent Office: 979 Days
• Field of Search: 427/421, 427/422, 427/427, 427/458, 427/466, 427/468, 427/469, 427/472, 427/475, 427/562, 427/564, 427/565, 239/3, 239/4, 239/11, 239/13, 118/56, 118/57, 118/620, 118/624, 118/640
• US Class Current: 427/469
• CPC Class Codes: B22F 2009/0836 with electric or magnetic field or induction
• CPC Class Codes: B23K 20/004 Wire welding
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 3/0623 for shaped solder piece feeding, e.g. preforms, bumps, balls, pellets, droplets
• CPC Class Codes: B41J 2/085 Charge means, e.g. electrodes
• CPC Class Codes: B41J 2/09 Deflection means
• CPC Class Codes: G01N 33/6842 Proteomic analysis of subsets of protein mixtures with reduced complexity, e.g. membrane proteins, phosphoproteins, organelle proteins
• CPC Class Codes: H01L 21/67144 Apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates
• CPC Class Codes: H01L 21/6715 Apparatus for applying a liquid, a resin, an ink or the like H01L21/67126 takes precedence
• CPC Class Codes: H05K 2203/013 Inkjet printing, e.g. for printing insulating material or resist
• CPC Class Codes: H05K 2203/105 Using an electrical field; Special methods of applying an electric potential
• CPC Class Codes: H05K 3/3457 Solder materials or compositions; Methods of application thereof

Abstract

A solder jet apparatus 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.

Claims

1. A method for generating a continuous stream of liquid metal droplets comprising:

producing a continuous stream of liquid metal droplets; and

selectively directing said stream of liquid metal droplets in a first dimension and a second dimension, said selectively directing comprising;

raster scanning said stream of liquid metal droplets; and

blanking selectively said stream of liquid metal droplets.

2. The method according to claim 1, wherein said producing further comprises:

heating a metal to a liquid state;

controlling a temperature of said metal in said liquid state to maintain said metal in said liquid state.

3. The method according to claim 1, wherein said producing further comprises:

inducing a pressure on a source of liquid metal; and

vibrating said liquid metal to cause said liquid metal droplets to be formed as said pressure is induced on said source of liquid metal.

4. The method according to claim 3, wherein said pressure inducing is generated by a piezoelectric crystal driven by a given frequency to produce a desired pressure.

5. The method according to claim 3, wherein said vibrating is generated by a piezoelectric crystal driven by a selected frequency to produce a given vibration frequency sufficient enough to form droplets having a diameter substantially in the range of 40 microns to 300 microns.

6. The method according to claim 1, wherein said producing further comprises forming said liquid metal droplets having a substantially consistent diameter in the range of 40 microns to 300 microns.

7. The method according to claim 1, wherein said raster scanning comprises electrically charging said liquid metal droplets.

8. The method according to claim 7, wherein said raster scanning further comprises deflecting said electrically charged liquid metal droplets in said first dimension and said second dimension.

9. The method according to claim 1, wherein said blanking comprises blanking when said stream of liquid metal droplets is positioned between an endpoint of a first line and a start point of a second line.

10. The method according to claim 1, wherein said blanking further comprises:

deflecting said stream of liquid metal droplets; and

catching said deflected stream of liquid droplets prior to being deposited on a selected surface.

11. The method according to claim 1, wherein said selectively directing comprises programmably controlling a direction of said stream of liquid metal droplets.