Method for selectively applying solder mask

• US 6,641,865 B2
• Filed: 12/31/2002
• Issued: 11/04/2003
• Est. Priority Date: 09/11/2000
• Status: Expired due to Fees

• Current Assignee: Proteinix, Inc.
• Original Assignee: Proteinix, Inc.
• Inventors: Hertz, Allen D.
• Primary Examiner(s): Talbot, Brian K.
• Application Number:
  US10/334,756
• Publication Number:
  US 20030099768A1
• Time in Patent Office: 308 Days
• Field of Search: 427/96, 427/282, 427/140, 118/504, 228/119
• US Class Current: 427/140
• CPC Class Codes: H05K 1/0269 for visual or optical inspection
• CPC Class Codes: H05K 13/0465 by soldering H05K13/0469 takes precedence
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer
• CPC Class Codes: H05K 2201/10734 Ball grid array [BGA]; Bump grid array
• CPC Class Codes: H05K 2203/0108 Male die used for patterning, punching or transferring
• CPC Class Codes: H05K 2203/0537 Transfer of pre-fabricated insulating pattern
• CPC Class Codes: H05K 2203/166 Alignment or registration; Control of registration
• CPC Class Codes: H05K 2203/176 Removing, replacing or disconnecting component; Easily removable component
• CPC Class Codes: H05K 3/1216 by screen printing or stencil printing
• CPC Class Codes: H05K 3/225 Correcting or repairing of printed circuits H05K1/0292, H05K3/222, H05K3/288, H05K3/4685 take precedence
• CPC Class Codes: H05K 3/3452 Solder masks

Abstract

A method is disclosed for applying solder mask to an area respective of a plurality of receiving pads on a Printed Circuit Board. The solder mask can be at least partially removed during the component removal process exposing the conductor, via and annular ring. The exposed conductor, via and annular ring can cause defects and unreliable solder joints should the solder flow along the conductor and into the via. A small stencil can be used to apply solder mask in a desirable pattern to a selective area of a PCB. Alternatively, an elastomeric transferring apparatus can be used. Various methods can be included to assist in aligning the applicator to the desired area such as an overlaid, dual imaging system.

Claims

1. A method of selectively applying solder mask to a Printed Circuit Board, the method comprising the steps:

repairing solder mask having been damaged as a result of removing at least one of a component and solder from the Printed Circuit Board,

registering a selective solder mask applicator, the selective solder mask applicator comprising a pattern for applying a solder mask material, to a pattern of electronic pads respective to the damaged solder mask of the Printed Circuit Board, and

applying the solder mask material proximate the pattern of electronic pads respective to the damaged solder mask on the Printed Circuit Board, wherein the solder mask material is applied between the electronic pads and leaving the electronic pads exposed.

2. The method of claim 1 wherein the selective solder mask applicator is a stencil comprising a plurality of apertures.

3. The method of claim 1, the method further comprising the step of

applying the solder mask material to the solder mask applicator, wherein the solder mask applicator is a transferring apparatus.

4. The method of claim 3, the transferring apparatus comprising a replicated array pattern, wherein the method further comprises the step of reducing the replicated array pattern on the transferring apparatus to correspond to the pattern of electronic pads respective to the damaged solder mask on the Printed Circuit Board.

5. The method of claim 3, the transferring apparatus comprising a transferring surface and a pattern of recessions, wherein the transferring surface is used to transfer the solder mask and the pattern of recessions is similar to the pattern of electronic pads on the Printed Circuit Board to avoid transference of the solder mask.

6. The method of claim 5, wherein the transferring apparatus is of an elastomeric material.

7. The method of claim 5, wherein the transferring surface further comprises at least one of texturing and recessions to enhance the transferring process.

8. A method of selectively applying solder mask to a Printed Circuit Board, the method comprising the steps:

repairing solder mask having been damaged as a result of removing at least one of a component and solder from the printed circuit board,

registering a selective solder mask applicator, the selective solder mask applicator comprising a pattern for applying a heat curable solder mask material, to a pattern of electronic pads respective to the damaged solder mask of the Printed Circuit Board, and

applying the heat curable solder mask material proximate the pattern of electronic pads respective to the damaged solder mask on the Printed Circuit Board, wherein the heat curable solder mask is applied between the electronic pads and leaving the electronic pads exposed,

and applying heat to cure the heat curable solder mask.

9. The method of claim 8 wherein the selective solder mask applicator is a stencil comprising a plurality of apertures.

10. The method of claim 8, the method further comprising the step of

applying the heat curable solder mask material to the solder mask applicator, wherein the solder mask applicator is a transferring apparatus.

11. The method of claim 10, the transferring apparatus comprising a transferring surface and a pattern of recessions, wherein the transferring surface is used to transfer the heat curable solder mask material and the pattern of recessions is similar to the pattern of electronic pads on the Printed Circuit Board to avoid transference of the heat curable solder mask material.

12. The method of claim 11, wherein the transferring apparatus is of an elastomeric material.

13. The method of claim 11, wherein the transferring surface further comprises at least one of texturing and recessions to enhance the transferring process.

14. A method of selectively applying solder mask to a Printed Circuit Board, the method comprising the steps:

repairing solder mask having been damaged as a result of removing at least one of a component and solder from the printed circuit board,

registering a selective solder mask applicator to a pattern of electronic pads respective to the damaged solder mask on an Printed Circuit Board, wherein the solder mask applicator is at least one of a stencil and a material transferring apparatus, and

applying the solder mask material proximate the pattern of electronic pads respective to the damaged solder mask on an Printed Circuit Board, wherein the solder mask material is applied between the electronic pads and leaving the electronic pads exposed.

15. The method of claim 14, the method further comprising the steps of using a magnifier to aid in registration of the selective solder mask applicator to the pattern of electronic pads respective to the single component of an Printed Circuit Board.

16. The method of claim 15 wherein the step of registering further includes a prism.

17. The method of claim 15 wherein the solder mask material is heat curable and the method further comprising the steps of applying heat for curing the solder mask material.

18. The method of claim 14, the solder mask applicator comprising a replicated array pattern, wherein the method further comprises the step of reducing the replicated array pattern on the solder mask applicator to correspond to the pattern of electronic pads respective to the damaged solder mask on the Printed Circuit Board.

19. The method of claim 14, the method further comprising the steps:

removing a component from the Printed Circuit Board, and

removing any residual solder from the pattern of electronic pads respective to the single component of the Printed Circuit Board.

20. The method of claim 19, the method further comprising the step of replacing the single component onto the Printed Circuit Board.