Application of acoustic and vibrational energy for fabricating bumped IC die and assembly of PCA's

• US 7,293,567 B2
• Filed: 12/16/2003
• Issued: 11/13/2007
• Est. Priority Date: 07/24/1999
• Status: Expired due to Fees

• Current Assignee: Allen David Hertz, Dennis D. Epp, Eric Lee Hertz
• Original Assignee: Allen David Hertz, Dennis D. Epp, Eric Lee Hertz
• Inventors: Hertz, Allen David, Epp, Dennis D., Hertz, Eric Lee
• Primary Examiner(s): Tran; Len
• Application Number:
  US10/737,240
• Publication Number:
  US 20040124230A1
• Time in Patent Office: 1,428 Days
• Field of Search: 228/201, 228/33, 228/39, 228/199, 101/123, 101/129, 134/1, 134/1.3, 134/6, 134/16, 134/25.4
• US Class Current: 134/1.3
• CPC Class Codes: B08B 7/028 Using ultrasounds
• CPC Class Codes: B41F 35/005 for flat screens
• CPC Class Codes: B41P 2235/14 using ultrasonic energy
• CPC Class Codes: F26B 5/02 by using ultrasonic vibrations using sonic energy generated by pulse jet combustion F26B23/026
• CPC Class Codes: F26B 5/12 by suction
• CPC Class Codes: H05K 3/1216 by screen printing or stencil printing
• CPC Class Codes: H05K 3/227 Drying of printed circuits
• CPC Class Codes: H05K 3/26 Cleaning or polishing of the conductive pattern

Abstract

A method and apparatus are disclosed for improving a screen printing process by applying vibrational energy to assist in the print release, cleaning, and drying processes. The vibrational energy or acoustic pressure waves may be created by a transducer where the waves are transferred to the stencil or printable material through air or a vibrational interface medium. The vibrational energy in turn assists with separating the printable material from the side walls of the apertures of the stencil. The vibrational energy can further assist in the process of cleaning the stencil. The acoustic pressure can also be used in the drying process by having the waves impinge on the water droplets to atomize the droplets on the surface of the stencil. The technology can be used for the assembly of Printed Circuit Assemblies, Ball Grid Array IC Packages, Flip Chip, etc. The same technology may be applied to other cleaning processes for cleaning Printed Circuit Assemblies, tooling, and the like, whereby the cleaning processes can assist in cleaning within the cracks, crevices and hard to reach areas of connectors and other components, without undesirable heat.

Claims

1. A method for cleaning at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies, the steps comprising:

cleaning at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies by applying a fluid to said at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies via a fluid application apparatus,

applying a drying step utilizing vibrational energy in accordance with at least one of;

a) via a mechanical coupling a vibrational energy and said stencil by placing a material between a vibrational energy source and said stencil; and

b) via applying vibrational energy through the air, directing said vibrational energy towards the at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies,

wherein said vibrational energy is to aid in drying the at least one of electronic assemblies and tooling related to manufacture of electronic assemblies by applying vibrational energy to a section of said at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies via a vibrational energy application apparatus, wherein said vibrational energy application apparatus applies said vibrational energy after said fluid cleaning step, where said vibrational energy is applied for atomizing residual moisture droplets resident to the at least one of electronic assemblies and tooling related to manufacture of electronic assemblies.

2. The method of claim 1, the method further comprising the step of:

applying vibrational energy to aid in cleaning of at least one of electronic assemblies and tooling related to manufacture of electronic assemblies.

3. The method of claim 2, the method further comprising transferring the relational proximity of the vibrational energy source and the at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies to one another.

4. The method of claim 1, the method further comprising transferring the relational proximity of the vibrational energy source and the at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies to one another.

5. The method of claim 1, wherein the step of applying vibrational energy by transferring the vibrational energy for drying is accomplished by:

applying vibrational energy through the air, wherein said vibrational energy is directed towards the at least one of electronic assembly, stencil, and tooling related to manufacture of electronic assemblies.

6. A method for cleaning a solder stencil, the method comprising the steps:

applying a fluid to a section of a solder stencil for cleaning said solder stencil for a fluid cleaning process,

applying vibrational energy by at least one of mechanically coupling a vibrational energy source and the solder stencil and transferring the vibrational energy through the air directed towards the solder stencil,

moving said vibrational energy source respective to said solder stencil, and

applying said vibrational energy to apply a vibrational energy to said solder stencil, wherein said vibrational energy application apparatus applies said vibrational energy after the fluid cleaning process, where said vibrational energy is applied to assist in drying any residual fluid from said solder stencil by atomizing said residual fluid away from a top surface of said solder stencil.

7. The method of claim 6, the method further comprising the step:

transferring the relational proximity of the vibrational energy source and the solder stencil to one another.

8. The method of claim 7, the method further comprising the step:

applying vibrational energy to the fluid to assist in a cleaning process.

9. The method of claim 6, the method further comprising the step:

applying vibrational energy to the fluid to assist in a cleaning process.

10. The method of claim 9, the method further comprising the steps commonly associated with automated solder screen printing, the commonly associated steps of solder screen printing comprising aligning electronic pads of a printed circuit board and apertures of the solder stencil, passing solder paste across apertures of a stencil, and separating the printed circuit board and the solder stencil.

11. The method of claim 6, the method further comprising the steps commonly associated with automated solder screen printing, the commonly associated steps of solder screen printing comprising aligning electronic pads of a printed circuit board and apertures of the solder stencil, passing solder paste across apertures of a stencil, and separating the printed circuit board and the solder stencil.

12. The method of claim 6, the method further comprising the step:

wiping the stencil with the wiping material.

13. The method of claim 12, method further comprising the step:

applying a vacuum force to aid in cleaning the stencil, wherein said vacuum force applies a vacuum force from underneath and proximate the stencil.

14. The method of claim 6, the method further comprising the step:

applying a vacuum force to aid in cleaning the stencil.

15. A method for cleaning and drying a stencil, the method comprising the steps:

aligning at least one of;

a printed circuit board to the stencil and an Integrated Circuit (IC) Wafer to the stencil, the stencil comprising at least one aperture,

positioning the printed circuit board proximate the stencil;

passing a printable medium across the at least one aperture of the stencil to apply a pattern of printable medium onto at least one of the printed circuit board and the IC wafer,

applying a fluid based cleaning process to at least one of the stencil and a wiping material; and

applying vibrational energy by at least one of;

through the air,

via mechanical contact to the stencil, and

to the wiping material,

wherein said vibrational energy is applied towards said solder stencil, wherein said vibrational energy application apparatus applies said vibrational energy after said fluid cleaning process, where said vibrational energy is applied to aid in drying the stencil wherein said vibrational energy for drying is applied in a manner to evaporate the material via the top of said stencil.

16. The method of claim 15, the method further comprising the step:

applying the vibrational energy to aid in cleaning the stencil.

17. The method of claim 15, the method further comprising the step:

wiping the stencil with the wiping material.

18. The method of claim 16, the method further comprising the step:

applying a vacuum force to aid in cleaning the stencil, wherein said vacuum force applies a vacuum force from underneath and proximate the stencil.

19. The method of claim 16, the method further comprising the step:

solidifying said printable medium applied onto the IC wafer.

20. The method of claim 16, the method further comprising the step:

applying vibrational energy to assist in releasing the printable medium from said stencil.