THREE-DIMENSIONAL INDUCTANCE COIL AND A METHOD FOR PRODUCING THE SAME IN PRINTED CIRCUIT BOARD

Abstract

A three-dimensional inductance coil and a method for producing the same in printed circuit board are provided. The method comprises the following steps: 1) Drilling through-holes on a twin surface copper-clad laminate bilaterally, to form two rows of through-holes on the twin surface copper-clad laminate; 2) cleaning the interior of through-holes; 3) Copper-plating the walls of the through-holes to form a copper layer thereon; 4) filling the through-holes with copper fully to form the first copper column row and the second copper column row in the twin surface copper-clad laminate; 5) Attaching photosensitive dry films to twin surfaces of the copper-clad laminate, and exposing and developing the dry films to perform patterns on twin surfaces of the copper-clad laminate, then etching the twin surfaces of the copper-clad laminate, thereby the first and the second copper column rows, as well as several separate upper and lower traces are made, wherein the top of the (n+1)th column of the first copper column row is connected to the top of the nth column of the second copper column row through one upper trace, and the bottom of the nth column of the first copper column row is connected to the bottom of the nth column of the second copper column row through one lower trace. This method features high efficiency.

Claims

1. A method for producing a three-dimensional inductance coil in printed circuit board, comprising the steps of 1) Drilling through-holes on a twin surface copper-clad laminate bilaterally, to form two rows of through-holes on the twin surface copper-clad laminate; 2) Cleaning the interior of the through-holes to remove a residue after drilling; 3) Copper-plating the walls of the through-holes to form a copper layer thereon; 4) Filling the through-holes with copper fully to form a first copper column row and a second copper column row in the twin surface copper-clad laminate; and 5) Attaching photosensitive dry films to twin surfaces of the copper-clad laminate, and exposing and developing the dry films to perform patterns on twin surfaces of the copper-clad laminate, then etching the twin surfaces of the copper-clad laminate, thereby the first and the second copper column rows, as well as several separate upper and lower traces are made, wherein the top of the (n+1)th column of the first copper column row is connected to the top of the nth column of the second copper column row through one upper trace, and the bottom of the nth column of the first copper column row is connected to the bottom of the nth column of the second copper column row through one lower trace, where n is an integer and no less than 1.

2. The method of claim 1, wherein the drilling process of the step 1) is a UV laser drilling process; the cleaning process of the step 2) is a watery degumming process.

3. The method of claim 1, wherein the copper layer of the step 3) is made by an electroless copper metallization process.

4. The method of claim 1, wherein a thickness of the copper layer of the step 3) is 2-3 m.

5. The method of claim 1, wherein the filing process of the step 4) is a copper-plating process.

6. The method of claim 1, wherein the two rows of through-holes are parallel one another, the intervals between two adjacent through-holes in the two rows of through-holes are identical.

7. A three-dimensional inductance coil comprising a first copper column row, a second copper column row, and several conductive upper and lower traces; the top of the (n+1)th column of the first copper column row is connected to the top of the nth column of the second copper column row through the one upper trace, and the bottom of the nth column of the first copper column row is connected to the bottom of the nth column of the second copper column row through the one lower trace, where n is an integer and no less than 1.

8. The three-dimensional inductance coil of claim 7, wherein the first and second copper column rows are parallel one another, the intervals between two adjacent columns in the first and second copper column rows are identical.

9. The three-dimension inductance coil of claim 7, wherein said three-dimension inductance coil is produced by the method of any of claim 1.

10. The three-dimension inductance coil of claim 7, wherein said three-dimension inductance coil is produced by the method of any of claim 2.

11. The three-dimension inductance coil of claim 7, wherein said three-dimension inductance coil is produced by the method of any of claim 3.

12. The three-dimension inductance coil of claim 7, wherein said three-dimension inductance coil is produced by the method of any of claim 4.

13. The three-dimension inductance coil of claim 7, wherein said three-dimension inductance coil is produced by the method of any of claim 5.

14. The three-dimension inductance coil of claim 7, wherein said three-dimension inductance coil is produced by the method of any of claim 6.

15. The three-dimension inductance coil of claim 8, wherein said three-dimension inductance coil is produced by the method of any of claim 1.

16. The three-dimension inductance coil of claim 8, wherein said three-dimension inductance coil is produced by the method of any of claim 2.

17. The three-dimension inductance coil of claim 8, wherein said three-dimension inductance coil is produced by the method of any of claim 3.

18. The three-dimension inductance coil of claim 8, wherein said three-dimension inductance coil is produced by the method of any of claim 4.

19. The three-dimension inductance coil of claim 8, wherein said three-dimension inductance coil is produced by the method of any of claim 5.

20. The three-dimension inductance coil of claim 8, wherein said three-dimension inductance coil is produced by the method of any of claim 6.

Description

BRIEF DESCRIPTION

[0026] FIG. 1 is a schematic view of through-holes made in step 1) of embodiment of the present invention;

[0027] FIG. 2 is a schematic view of a twin surface copper-clad laminate having the through-holes;

[0028] FIG. 3 is a schematic view of a twin surface copper-clad laminate having the through-holes which are plated and filled by copper;

[0029] FIG. 4 is a schematic view of a circuit on upper surface of the copper-clad laminate;

[0030] FIG. 5 is a schematic view of a circuit on lower surface of the copper-clad laminate;

[0031] FIG. 6 is a schematic view of a three-dimensional inductance coil fabricated in embodiment of the present invention.

DETAILED DESCRIPTION

[0032] The present invention will be described hereinafter with reference to the following embodiment and figures.

Embodiment

[0033] A three-dimensional inductance coil is fabricated by the steps of: [0034] 1) Getting a twin surface copper-clad laminate where a substrate having thickness of 50 m is sandwiched between twin surfaces made of copper foils having thickness of 18 m and; two parallel rows of holes thereon can be designed by AutoCAD software, there would be a first row 1 and a second row 2, and each row involves six holes with a 50 m diameter. As shown in FIG. 1, the intervals D2 between centers of two adjacent holes in the same row is 450 m, and the intervals D1 between centers of two neighboring holes in the two rows is 4950 m. As shown in FIG. 2, the corresponding two parallel rows of through-holes, i.e. a first row of through-holes 11, and a second row of through-holes 21, can be made on the copper-clad laminate 3 by UV laser drilling a copper-clad laminate 3 bilaterally; [0035] 2) Cleaning the interior of through-holes by watery degumming process to remove the residual gumming after drilling, and making the hole walls rough with surface roughness (Ra) of 500-1000 nm, so as to facilitate the subsequent electroless copper adhering and depositing; [0036] 3) Copper-plating the through-holes walls adopting electroless copper metallization technology which includes 30-second activation process, 10-second microetch process and 50-minute deposition process to ensure the thickness of plating copper on the through-holes walls at approximately 1 m; [0037] 4) Copper-plating the through-holes until full of copper so as to form a first copper column row 4 and a second copper column row 5 in the copper-clad laminate, as shown in FIG. 3; the solution used in this copper-plating technology mainly comprises copper sulfate pentahydrate (22020 g/L), sulphuric acid (5010 g/L), chloride complex (5010 ppm), accelerator (3620 A, 1.00.2 mL/L), inhibitor (3620 S, 153 mL/L), leveler (3620 L, 153 mL/L), wherein the accelerator, inhibitor and leveler is manufactured by Shanghai Xinyang Semiconductor Material Co. Ltd; and [0038] 5) Attaching photosensitive dry films to the twin surfaces of the copper-clad laminate, and a circuit pattern designed by AutoCAD software, as shown in FIGS. 4 & 5, is projected to the dry films by exposure machine, then the exposed dry film is developed and a circuit pattern is shown on the twin surfaces of the copper-clad laminate; after an etching process to the twin surfaces of the copper-clad laminate, three-dimensional inductance coil is therefore formed. In the etching process, a subtractive process or an semi-additive process is generally used, wherein subtractive process is a method that dry film protects circuit pattern from being etched while unprotected parts will be removed, and semi-additive process is a method that the dry film protects the parts except the circuit pattern while the circuit pattern is copper-plated such that the copper thickness in circuit pattern exceeds that of non-circuit pattern, then thin copper on the non-circuit pattern can be etched completely after an etching process, meanwhile as copper layer of the circuit pattern are perfectly thick and remain adequate, so as to form an inductance coil.

[0039] As shown in FIG. 6, the three-dimensional inductance coil fabricated by step 5 comprises the first copper column row 4, the second copper column row 5, five upper traces 6 positioned on upper surface of the copper-clad laminate and six lower traces 7 positioned on lower surface of the copper-clad laminate, wherein the top of the (n+1)th column of the first copper column row is connected to the top of the nth column of the second copper column row through one upper trace, and the bottom of the nth column of the first copper column row is connected to the bottom of the nth column of the second copper column row through one lower trace, where n is an integer and no less than 1, the solid lines in FIG. 6 depicts a three-dimensional inductance coil. For example, the top of the second column 42 of the first copper column row is connected to the top of the first column 51 of the second copper column row through one upper trace 6, and the bottom of the first column 41 of the first copper column row is connected to the bottom of the first column 51 of the second copper column row through one lower trace 7, and so on.

[0040] The present method for producing a three-dimensional inductance coil with six copper turns is effective, and meanwhile the coil produced by this method has higher inductance values as compared to the planar inductance coil with same turns.

[0041] The embodiment described hereinbefore is merely preferred embodiment of the present invention and not for purposes of any restrictions or limitations on the invention. It will be apparent that any non-substantive, obvious alterations or improvement by the technician of this technical field according to the present invention may be incorporated into ambit of claims of the present invention.