Method for fabricating electrically connecting structure of circuit board

• US 20060252248A1
• Filed: 05/08/2006
• Published: 11/09/2006
• Est. Priority Date: 05/09/2005
• Status: Abandoned Application

• Current Assignee: Phoenix Precision Technology Corporation (Unimicron Technology Corporation)
• Original Assignee: Phoenix Precision Technology Corporation (Unimicron Technology Corporation)
• Inventors: Hu, Wen-Hung
• Application Number:
  US11/429,882
• Publication Number:
  US 20060252248A1
• Time in Patent Office: Days
• US Class Current: 438/613
• CPC Class Codes: H05K 2201/0367 Metallic bump or raised conductor not used as solder bump
• CPC Class Codes: H05K 2203/0353 Making conductive layer thin, e.g. by etching
• CPC Class Codes: H05K 2203/054 Continuous temporary metal layer over resist, e.g. for selective electroplating
• CPC Class Codes: H05K 2203/0723 Electroplating, e.g. finish plating
• CPC Class Codes: H05K 3/045 by making a conductive layer having a relief pattern, followed by abrading of the raised portions
• CPC Class Codes: H05K 3/243 characterised by selective plating, e.g. for finish plating of pads selective plating for making the circuit pattern H05K3/108, H05K3/182
• CPC Class Codes: H05K 3/28 Applying non-metallic protective coatings H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673
• CPC Class Codes: H05K 3/4007 Surface contacts, e.g. bumps H05K3/4092 takes precedence; deposition of finish layers on pads H05K3/24; forming solder bumps H05K3/3457

Abstract

A method for fabricating an electrically connecting structure of a circuit board is proposed. An insulating protecting layer is formed on a circuit board having electrically connecting pads and has openings to expose the electrically connecting pads. A resist layer with openings corresponding to the electrically connecting pads is formed on a conductive layer formed on the insulating protecting layer. A metal layer is formed in the openings of the resist layer and fills the openings. The resist layer is removed. The metal layer and the conductive layer on the surface of the insulating protecting layer are removed by thinning processing, so as to form a metal bump. An adhesive layer is formed on an exposed surface of the metal bump, so as to form the electrically connecting structure for electrically connecting the circuit board to an external electronic device.

Claims

1. A method for fabricating an electrically connecting structure of a circuit board, the method comprising:

providing a circuit board comprising a plurality of electrically connecting pads on at least one surface of the circuit board, and forming on the surface of the circuit board an insulating protecting layer comprising a plurality of openings for exposure of the electrically connecting pads;

forming a conductive layer on the insulating protecting layer and the openings of the insulating protecting layer;

forming on the conductive layer a resist layer comprising a plurality of openings corresponding to the electrically connecting pads;

forming a metal layer on the conductive layer exposed by the openings of the resist layer with an electroplating process, and filling the metal layer in the openings of the insulating protecting layer;

removing the resist layer, and removing part of the metal layer and the conductive layer above the insulating protecting layer with a thinning process, so as to form on each of the electrically connecting pads a metal bump; and

forming an adhesive layer on a surface of the metal bump exposed by each of the openings of the insulating protecting layer, so as to form the electrically connecting structure for electrically connecting the circuit board to an external electronic device.

2. The method for fabricating an electrically connecting structure of a circuit board of claim 1, wherein the adhesive layer is one selected from a group consisting of a solder material, a metal layer and an organic solderability preservative (OSP) layer.

3. The method for fabricating an electrically connecting structure of a circuit board of claim 2, wherein the metal layer is one selected from a group consisting of a nickel/gold bi-metal layer, gold, electroless plating tin and electroless plating silver.

4. The method for fabricating an electrically connecting structure of a circuit board of claim 2 further comprising performing a reflow process on the solder material to form a solder bump on the metal bump.

5. The method for fabricating an electrically connecting structure of a circuit board of claim 1, wherein the metal layer is made of at least one selected from a group consisting of lead, tin, silver and copper.

6. The method for fabricating an electrically connecting structure of a circuit board of claim 1, wherein the thinning process is one selected from a group consisting of an etching, a buff and an abrasive process.

7. A method for fabricating an electrically connecting structure of a circuit board, the method comprising:

providing a circuit board comprising a plurality of electrically connecting pads on at least one surface of the circuit board, and forming on the surface of the circuit board an insulating protecting layer comprising a plurality of openings for exposure of the electrically connecting pads;

forming a conductive layer on the insulating protecting layer and the openings of the insulating protecting layer;

forming a metal layer on the conductive layer with an electroplating process, and filling the metal layer in the openings of the insulating protecting layer;

removing part of the metal layer and the conductive layer above the insulating protecting layer with a thinning process, and keeping a remaining part of the metal layer and the conductive layer filled in the openings of the insulating protecting layer opening, so as to form on each of the electrically connecting pads a metal bump; and

forming an adhesive layer on a surface of the metal bump exposed by each of the openings of the insulating protecting layer, so as to form the electrically connecting structure for electrically connecting the circuit board to an external electronic device.

8. The method for fabricating an electrically connecting structure of a circuit board of claim 7, wherein the adhesive layer is one selected from a group consisting of a solder material, a metal layer and an OSP layer.

9. The method for fabricating an electrically connecting structure of a circuit board of claim 8, wherein the metal layer is one selected from a group consisting of a nickel/gold bi-metal layer, gold, electroless plating tin and electroless plating silver.

10. The method for fabricating an electrically connecting structure of a circuit board of claim 8 further comprising performing a reflow process on the solder material to form a solder bump on the metal bump.

11. The method for fabricating an electrically connecting structure of a circuit board of claim 7, wherein the metal layer is made of at least one selected from a group consisting of lead, tin, silver and copper.

12. The method for fabricating an electrically connecting structure of a circuit board of claim 7, wherein the thinning process is one selected from a group consisting of an etching, a buff and an abrasive process.

13. A method for fabricating an electrically connecting structure of a circuit board, the method comprising:

providing a circuit board comprising a plurality of electrically connecting pads on at least one surface of the circuit board, and forming on the surface of the circuit board an insulating protecting layer having a plurality of openings for exposure of the electrically connecting pads;

forming a conductive layer on the insulating protecting layer and the openings of the insulating protecting layer;

forming on the conductive layer a resist layer having a plurality of openings corresponding to the electrically connecting pads;

forming a metal layer on the conductive layer exposed by the openings of the resist layer with an electroplating process, and filling the metal layer in the openings of the insulating protecting layer;

removing the metal layer and the conductive layer above the insulating protecting layer with a thinning process, and keeping the metal layer and the conductive layer filled in the openings of the insulating protecting layer, so as to form a metal bump on each of the electrically connecting pads; and

removing the resist layer and the conductive layer covered by the resist layer, and forming an adhesive layer on a surface of the metal bump exposed by each of the openings of the insulating protecting layer, so as to form the electrically connecting structure for electrically connecting the circuit board to an external electronic device.

14. The method for fabricating an electrically connecting structure of a circuit board of claim 13, wherein the adhesive layer is one selected from a group consisting of a solder material, a metal layer and an OSP layer.

15. The method for fabricating an electrically connecting structure of a circuit board of claim 14, wherein the metal layer is one selected from a group consisting of a nickel/gold bi-metal layer, gold, electroless plating tin and electroless plating silver.

16. The method for fabricating an electrically connecting structure of a circuit board of claim 14 further comprising performing a reflow process on the solder material to form a solder bump on the metal bump.

17. The method for fabricating an electrically connecting structure of a circuit board of claim 13, wherein the metal layer is made of at least one selected from a group consisting of lead, tin, silver and copper.

18. The method for fabricating an electrically connecting structure of a circuit board of claim 13, wherein the thinning process is performed by the use of an etching process.