LIGHT EMITTED DIODE SUBSTRATE AND METHOD FOR PRODUCING THE SAME

• US 20110079814A1
• Filed: 10/01/2009
• Published: 04/07/2011
• Est. Priority Date: 10/01/2009
• Status: Abandoned Application

• Current Assignee: Chen-Yi Chang
• Original Assignee: Chen-Yi Chang
• Inventors: Chen, Yi-Chang
• Application Number:
  US12/571,481
• Publication Number:
  US 20110079814A1
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H05K 1/053 the metal substrate being covered by an inorganic insulating layer
• CPC Class Codes: H05K 2201/0355 Metal foils
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2203/0369 Etching selective parts of a metal substrate through part of its thickness, e.g. using etch resist
• CPC Class Codes: H05K 2203/0522 Using an adhesive pattern
• CPC Class Codes: H05K 3/06 the conductive material being removed chemically or electrolytically, e.g. by photo-etch process semi-additive methods H05K3/108
• CPC Class Codes: H05K 3/244 Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473

Abstract

A method for producing the LED substrate has steps of: p providing a conductive metallic board, forming multiple grooves in a top of the conductive metallic board; protecting the conductive metallic board from corrosion, forming an etched substrate with circuits and wires for plating on the conductive metallic board, electroless plating the etched substrate to form an electroless plated substrate, plating metal on the electroless plated substrate, and coating solder mask to obtain the LED substrate. Because LED chips are mounted on the surfaces of the metal layer without insulating adhesive below, heat from LED chips can be dissipated efficiently. The LED substrate of the present invention can be soldered directly onto a dissipation module to further enhance dissipation efficiency.

Claims

1. A method for producing a light emitted diode (LED) substrate comprising steps of:

providing a conductive metallic board with a top, a bottom and four sides and the conductive metallic board is made of aluminum (Al) or copper (Cu);

forming multiple grooves in the top of the conductive metallic board;

protecting the conductive metallic board from corrosion;

forming multiple copper layers having forming multiple copper layers on the conductive metallic board to be served as circuits and wires for plating and exposing the top of the conductive metallic board with the conversion coating and without contacting the adhesive layers to form an etched substrate;

electroless plating the etched substrate including pretreating the etched substrate and immersing the etched substrate into an electroless nickel (Ni) plating bath and electroless plating all exposing metal of the etched substrate to form an electroless plated substrate with electroless Ni layers;

attaching a thermal resistant adhesive tape on a bottom of the electroless plated substrate;

plating metal on the electroless plated substrate at least having a step of plating spraying tin or plating gold or plating silver on a top of the electroless plated substrate; and

coating solder mask partially on the metal to obtain the LED substrate.

2. The method as claimed in claim 1, wherein the step of forming multiple copper layers has

providing a flexible plastic board, an upper copper foil and a lower copper foil;

respectively pressing the upper and lower copper foils to an upper surface and a lower surface of the flexible plastic board to form a copper plastic board, wherein the upper and lower copper foils are served as two electrodes;

mechanically processing the copper plastic board to form multiple through holes in the copper plastic board according to the pre-determined pattern;

etching the upper and lower copper foils to form pretreated circuits and wires for plating;

immersing the copper plastic board into a copper sulphate (CuSO₄) solution to plate the copper plastic board to form plated layers with a thickness of 10˜

15 μ

m on surfaces of the upper and lower copper foils and inner walls of the through holes to communicate with the upper and lower copper foils;

etching the copper plastic board to form circuits and wires for plating;

screen-printing insulating adhesives on the lower copper foils of the copper plastic board;

pressing the copper plastic board on the conductive metallic board at 150˜

200°

C. for 30˜

50 minutes to form multiple copper layers and multiple adhesive layers;

exposing the top of the conductive metallic board covered with the conversion coating to form an etched substrate with copper layers served as circuits and wires for plating.

3. The method as claimed in claim 1, wherein the step of forming multiple copper layers has

screen-printing insulating adhesives on the conversion coatings in the grooves of the conductive metallic board to form multiple adhesive layers;

pressing a copper foil onto the adhesive layers under 150˜

200°

C. for 30˜

50 minutes;

etching the copper foil without connecting the adhesive layers according to the pre-determined pattern to form an etched substrate with copper layers served as circuits and wires for plating and partially exposing the top of the conductive metallic board with the conversion coating.

4. The method as claimed in claim 2, wherein the adhesive layer is made of phenyl novolac epoxy and has a thickness of less than 0.05 mm.

5. The method as claimed in claim 3, wherein the adhesive layer is made of phenyl novolac epoxy and has a thickness of less than 0.05 mm.

6. The method as claimed in claim 1, wherein the step of protecting the conductive metallic board from corrosion comprises conversion coating the top, the bottom and the sides of the conductive metallic board with fluoride or chromate including trivalent chromium to form a conversion coating with a thickness of about 0.1˜

1 micrometer (nm).

7. The method as claimed in claim 1, wherein when the conductive metallic board is made of Al, the step of electroless plating the etched substrate comprises immersing the etched substrate into an electroless nickel plating bath, wherein the conductive metallic board is electroless plated by zinc (Zn) replacement and the copper layer is electroless plated by contact plating via the wires for plating.

8. The method as claimed in claim 1, wherein when the conductive metallic board is made of Cu, the step of electroless plating the etched substrate comprises immersing the etched substrate into an electroless nickel plating bath, wherein the conductive metallic board and the copper layer are electroless plated by contact plating via the wires for plating.

9. The method as claimed in claim 1, wherein the step of plating metal on the electroless plated substrate further has steps of:

plating copper (Cu) comprises plating Cu on the electroless Ni layer;

plating nickel (Ni) comprises plating Ni on the plated Cu layer to form a plated Ni layer; and

the step of spraying tin, plating gold or plating silver comprises spraying tin, plating gold or plating silver on the plated Ni layer.

10. A light emitted diode (LED) substrate, comprising:

a conductive metallic board being made of Al or Cu and having

a top;

a bottom;

multiple grooves formed in the top of the conductive metallic board according to a pre-determined pattern; and

multiple adhesive layers formed in the grooves in the conductive metallic board;

multiple copper layers formed on the adhesive layers;

multiple electroless Ni layers electroless plated over the copper layers and the top of the conductive metallic board without covered by the adhesive layers;

multiple metal layers mounted on the electroless Ni layers above the top of the conductive metallic board and each metal layer at least having a tin layer or gold layer or silver layer mounted on the electroless Ni layers; and

a solder mask layer partially applied on the metal layer to expose surfaces of the metal layer without copper layer below adapted for attaching LED chips and with copper layer below adapted for bonding wires.

11. The LED substrate as claimed in claim 10, wherein each copper layer comprises

a flexible plastic board having an upper surface and a lower surface;

an upper copper foil pressed on the upper surface of the flexible plastic board;

a lower copper foil pressed on the lower surface of the flexible plastic board;

multiple through holes formed in the copper layer through the upper copper foil, the flexible plastic board and the lower copper foil and each through hole having an inner wall; and

multiple plated layers plated on the inner walls of the through holes to electrically communicate with the upper copper foil and the lower copper foil.

12. The LED substrate as claimed in claim 10, wherein each copper layer is made of a copper foil.

13. The LED substrate as claimed in claim 10, wherein

each groove has a thickness of at least 0.05 mm;

and

each adhesive layer is made of phenyl novolac epoxy and has a thickness of less than 0.05 mm.

14. The LED substrate as claimed in claim 10, wherein the metal layer further has

a plated copper layer formed between the electroless Ni layer and the tin layer or gold layer or silver layer;

and

a plated Ni layer formed between the plated copper layer and the tin layer or gold layer or silver layer.

15. The LED substrate as claimed in claim 10, wherein the conductive metallic board further has multiple conversion coatings formed in the grooves, formed between the conductive metallic board and the adhesive layers, are made of trivalent chromium or fluoride and individually have a thickness of 0.1˜

1 μ

m.