Multilayer rigid flexible printed circuit board and method for manufacturing the same

Abstract

The present invention provides a multilayer rigid flexible printed circuit board including: a flexible region including a flexible film having a circuit pattern formed on one or both surfaces thereof and a laser blocking layer formed on the circuit pattern; and a rigid region formed adjacent to the flexible region and including a plurality of pattern layers on one or both surfaces of extended portions extended to both sides of the flexible film of the flexible region, and a method for manufacturing the same.

Claims

1. A multilayer rigid flexible printed circuit board comprising: a flexible film comprising a first circuit pattern on one or both surfaces, and having an area corresponding to a rigid region and a flexible region of the multilayer rigid flexible printed circuit board, the first circuit pattern comprising a first portion in the flexible region and a second portion in the rigid region; a first insulating layer disposed on the flexible film in the flexible region to cover the first portion of the first circuit pattern and having an extension portion extending into the flexible film in the rigid region; a first adhesive disposed between the first circuit pattern and the first insulating layer; a copper pattern positioned at the rigid region of the flexible film and disposed on the extension portion of the first insulating layer; a second insulating layer disposed on and in contact with the flexible film in the rigid region, covering the copper pattern, and comprising a second circuit pattern; and a plurality of conductive vias connecting to either one or both of the first circuit pattern and the second circuit pattern, wherein at least one of the plurality of conductive vias is not directly connected to the first circuit pattern.

2. The multilayer rigid flexible printed circuit board according to claim 1, wherein the copper pattern is physically isolated from the first circuit pattern and the second circuit pattern.

3. The multilayer rigid flexible printed circuit board according to claim 1, wherein the first insulating layer comprises a polyimide.

4. The multilayer rigid flexible printed circuit board according to claim 1, further comprising a second adhesive disposed between the first insulating layer and the copper pattern.

5. The multilayer rigid flexible printed circuit board according to claim 1, wherein the copper pattern is exposed on side surfaces of the first and the second insulating layers facing the flexible domain.

6. The multilayer rigid flexible printed circuit board according to claim 1, further comprising an electromagnetic shielding layer on the flexible film in the flexible region to cover the first circuit pattern formed thereon.

7. The multilayer rigid flexible printed circuit board according to claim 6, wherein the electromagnetic shielding layer comprises: an adhesive coated on the first circuit pattern formed on the flexible film; a polyimide layer formed on the adhesive to protect the first circuit pattern; and a copper foil layer formed on the polyimide layer.

8. The multilayer rigid flexible printed circuit board according to claim 6, wherein the electromagnetic shielding layer comprises: a third adhesive coated on the first circuit pattern formed on the flexible film; a polyimide layer formed on the third adhesive to protect the first circuit pattern; a fourth adhesive disposed on the polyimide layer; and a copper foil layer formed on the fourth adhesive.

9. The multilayer rigid flexible printed circuit board according to claim 1, wherein the rigid region further comprises at least one circuit pattern which is formed between a plurality of insulating layers to be electrically connected to either one or both of the first and the second circuit patterns.

10. The multilayer rigid flexible printed circuit board according to claim 1, wherein the rigid region further comprises an outer circuit pattern which is formed on the outermost upper surface of a plurality of insulating layers to be electrically connected to either one or both of the first and the second circuit patterns.

11. The multilayer rigid flexible printed circuit board according to claim 1, wherein the plurality of conductive vias are not directly connected to the portion of the first circuit pattern covered by the first insulating layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

(2) FIGS. 1 to 3 are views showing a cross section of a multilayer rigid flexible printed circuit board in accordance with a first embodiment of the present invention;

(3) FIGS. 4a and 4b are views showing a cross section of a laser blocking layer in accordance with an embodiment of the present invention;

(4) FIG. 5 is a view showing a cross section of a laser blocking layer in accordance with another embodiment of the present invention;

(5) FIGS. 6a and 6b are views showing various embodiments of a stacked structure of a laser blocking layer and an electromagnetic shielding layer in accordance with an embodiment of the present invention;

(6) FIGS. 7a and 7b are views showing various embodiments of a stacked structure of a laser blocking layer and an electromagnetic shielding layer in accordance with another embodiment of the present invention;

(7) FIGS. 8a to 8j are views showing a method for manufacturing a multilayer rigid flexible printed circuit board in accordance with an embodiment of the present invention;

(8) FIG. 9 is a view showing a cross section of a multilayer rigid flexible printed circuit board in accordance with a second embodiment of the present invention; and

(9) FIG. 10 is a view showing a cross section of a multilayer rigid flexible printed circuit board in accordance with a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to particular modes of practice, and it is to be appreciated that all changes, equivalents, and substitutes that do not depart from the spirit and technical scope of the present invention are encompassed in the present invention.

(11) A multilayer rigid flexible printed circuit board and a method for manufacturing the same in accordance with certain embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Those components that are the same or are in correspondence are rendered the same reference numeral regardless of the figure number, and redundant explanations are omitted.

(12) Multilayer Rigid Flexible Printed Circuit Board

(13) A multilayer rigid flexible printed circuit board in accordance with the present invention includes a flexible region F and a rigid region R. The flexible region F is a region which is made of a flexible material and where a bending portion is formed. The rigid region is a region which is made of a rigid material.

(14) The flexible region F includes at least one flexible film having a first circuit pattern formed on at least one surface thereof, and a laser blocking layer may be formed on at least one surface of the first circuit pattern.

(15) Further, an electromagnetic shielding layer may be further formed on the laser blocking layer of the flexible region F to shield electromagnetic waves.

(16) The rigid region R is formed adjacent to the flexible region F and may include a plurality of pattern layers on at least one surface of an extended portion of the at least one flexible film.

(17) Hereafter, various embodiments of the multilayer rigid flexible printed circuit board in accordance with the present invention will be specifically described.

Multilayer Rigid Flexible Printed Circuit Board

First Embodiment

(18) FIGS. 1 to 3 are views showing a cross section of a multilayer rigid flexible printed circuit board in accordance with a first embodiment of the present invention.

(19) As shown in FIGS. 1 to 3, a multilayer rigid flexible printed circuit board in accordance with a first embodiment of the present invention includes a flexible region F and a rigid region R, and a laser blocking layer 50 is formed in the flexible region F.

(20) The laser blocking layer 50 is formed on a base substrate 10 in the flexible region F, and a plurality of pattern layers 20, 30, and 40 are formed on the base substrate 10 in the rigid region R.

(21) First, when describing a structure of the flexible region F, the flexible region F has the structure in which the laser blocking layer 50 is formed on the base substrate 10.

(22) The base substrate 10 includes at least one flexible film 11 having a first circuit pattern 12 formed on at least one surface thereof, and the laser blocking layer 50 is formed on at least one surface of the first circuit pattern 12.

(23) The laser blocking layer 50 includes an adhesive 51, a polyimide layer 52, and a copper foil layer 53, and the adhesive 51 is disposed on the first circuit pattern 12.

(24) The polyimide layer 52 is formed to protect the first circuit pattern 12, the polyimide layer 52 and the first circuit pattern 12 are formed while interposing the adhesive 51 therebetween, and the copper foil layer 53 is formed on the polyimide layer 52.

(25) After copper plating 43 is performed on the copper foil layer 53 of the laser blocking layer 50 to form an outer layer circuit pattern, the outer layer circuit pattern is formed by etching portions of the copper plating 43 in correspondence to the circuit pattern (referring to FIGS. 2 and 3).

(26) The laser blocking layer 50 may be formed in various embodiments and will be described in detail in FIGS. 4a, 4b, and 5b.

(27) Further, the layer blocking layer 50 may be extended to the rigid region R.

(28) For example, each side surface of the copper foil layer 53 of the laser blocking layer 50 may be formed smaller than that of the polyimide layer 52 formed on a lower surface of the copper coil layer 53 by more than 10 m or the laser blocking layer 50 may be extended to the rigid region R from a boundary surface between the flexible region F and the rigid region R by 0.05 to 5 mm.

(29) Next, the rigid region R is formed adjacent to the flexible region F and includes a plurality of pattern layers 20, 30, and 40 on at least one surface of an extended portion of the at least one flexible film 11.

(30) Generally, one pattern layer is formed by sequentially stacking an insulator and a copper foil layer on a lower pattern layer, forming a via hole or a through hole in the insulator and the copper foil layer, performing copper plating on the insulator and the copper foil layer having the via hole or the through hole formed therein, and etching the insulator and the copper foil layer according to a circuit pattern.

(31) Here, the insulator may be prepreg or a rigid material, and the copper foil layer may be formed by a casting, laminating, or sputtering method.

(32) The via hole is a plated through hole formed on the insulator which is formed under the copper foil layer to be electrically connected to the lower circuit pattern, and the plated through hole passes through the base substrate to be electrically connected to the circuit pattern formed at an opposite side of the base substrate.

(33) The via hole or the through hole is a plated through hole formed by computer numerical control (CNC) drilling or laser drilling to electrically connect an outer layer circuit pattern and an inner layer circuit pattern.

(34) The multilayer rigid flexible printed circuit board in accordance with the present invention includes the plurality of pattern layers 20, 30, and 40 and a plurality of via holes A and B or through holes C and D for electrically connecting outer circuit patterns 42 and 43 and inner circuit patterns 12, 22, 23, 32, and 33.

Second Embodiment

(35) FIG. 9 is a view showing a cross section of a multilayer rigid flexible printed circuit board in accordance with a second embodiment of the present invention.

(36) As shown in FIG. 9, a multilayer rigid flexible printed circuit board in accordance with a second embodiment of the present invention includes a flexible region F and a rigid region R, and a laser blocking layer 50 and an electromagnetic shielding layer 60 are formed in the flexible region F.

(37) The other components are the same as those of a multilayer rigid flexible printed circuit board in accordance with a first embodiment, and only the components different from those of the multilayer rigid flexible printed circuit board in accordance with a first embodiment will be described in detail.

(38) The multilayer rigid flexible printed circuit board in accordance with a second embodiment has a structure in which the electromagnetic shielding layer 60 is further formed in a stacked structure of the multilayer rigid flexible printed circuit board in accordance with a first embodiment.

(39) That is, the laser blocking layer 50 and the electromagnetic shielding layer 60 are formed on a base substrate 10 in the flexible region F, and a plurality of pattern layers 20, 30, and 40 are formed on the base substrate 10 in the rigid region R.

(40) The laser blocking layer 50 may be formed on one surface of a single-sided printed circuit board or on both surfaces of a double-sided printed circuit board.

(41) The electromagnetic shielding layer 60 may be formed between the laser blocking layer 50 and a flexible film 11 of the single-sided printed circuit board or between the both laser blocking layers 50 and the flexible film 11 of the double-sided printed circuit board (referring to FIG. 9).

(42) Specifically, the flexible region F has a structure in which the electromagnetic shielding layer 60 is formed on the base substrate 10, and the base substrate 10 includes the at least one flexible film 11 having a first circuit pattern 12 formed on at least one surface thereof.

(43) The electromagnetic shielding layer 60 is formed on at least one or both surfaces of the first circuit pattern 12, and the laser blocking layer 50 is formed on the electromagnetic shielding layer 60 or on the flexible film 11 where the electromagnetic shielding layer 60 is not formed.

(44) The laser blocking layer 50 or the electromagnetic shielding layer 60 includes an adhesive 51 or 61, a polyimide layer 52 or 62, and a copper foil layer 53 or 63, and the adhesive 51 or 61 is disposed on the first circuit pattern 12.

(45) The polyimide layer 52 is formed to protect the first circuit pattern 12, the polyimide layer 52 and the first circuit pattern 12 are formed while interposing the adhesive 51 therebetween, and the copper foil layer 53 is formed on the polyimide layer 52.

(46) After copper plating 43 is performed on the copper foil layer 53 of the laser blocking layer 50 to form an outer layer circuit pattern, the outer layer circuit pattern is formed by etching portions of the copper plating 43 in correspondence to the circuit pattern (referring to FIG. 9).

(47) A stacked structure of the laser blocking layer 50 or the electromagnetic shielding layer 60 may be formed in various embodiments and will be described in detail in FIGS. 6a, 6b, 7a, and 7b.

(48) The laser blocking layer 50 or the electromagnetic shielding layer 60 may be extended to the rigid region R, and the laser blocking layer 50 or the electromagnetic shielding layer 60 extended to the rigid region R is not removed by laser processing.

(49) For example, the laser blocking layer 50 or the electromagnetic shielding layer 60 may be extended to the rigid region R from a boundary surface between the flexible region F and the rigid region R by 0.05 to 5 mm.

Third Embodiment

(50) FIG. 10 is a view showing a cross section of a multilayer rigid flexible printed circuit board in accordance with a third embodiment of the present invention.

(51) As shown in FIG. 10, a multilayer rigid flexible printed circuit board in accordance with a third embodiment of the present invention includes a flexible region F and a rigid region R, and a laser blocking layer 50 and an electromagnetic shielding layer 60 are formed in the flexible region F.

(52) The other components are the same as those of a multilayer rigid flexible printed circuit board in accordance with a first embodiment, and only the components different from those of the multilayer rigid flexible printed circuit board in accordance with a first embodiment will be described in detail.

(53) The multilayer rigid flexible printed circuit board in accordance with a third embodiment has a structure in which the electromagnetic shielding layer 60 is further formed in a stacked structure of the multilayer rigid flexible printed circuit board in accordance with a first embodiment, and a via hole A or a through hole C is formed in the laser blocking layer 50 and the electromagnetic shielding layer 60.

(54) The flexible region F has a structure in which the electromagnetic shielding layer 60 is formed on a base substrate 10, and the base substrate 10 includes at least one flexible film 11 having a first circuit pattern 12 formed on at least one surface thereof.

(55) The electromagnetic shielding layer 60 is formed on at least one or both surfaces of the first circuit pattern 12, and the laser blocking layer 50 is formed on the electromagnetic shielding layer 60 or on the flexible film 11 where the electromagnetic shielding layer 60 is not formed.

(56) The laser blocking layer 50 or the electromagnetic shielding layer 60 includes an adhesive 51 or 61, a polyimide layer 52 or 62, and a copper foil layer 53 or 63, and the adhesive 61 is disposed on the first circuit pattern 12.

(57) The polyimide layer 62 of the electromagnetic shielding layer 60 is formed to protect the first circuit pattern 12, the polyimide layer 62 and the first circuit pattern 12 are formed while interposing the adhesive 61 therebetween, and the copper foil layer 63 is formed on the polyimide layer 62.

(58) After copper plating 43 is performed on the copper foil layer 53 of the laser blocking layer 50 to form an outer layer circuit pattern, the outer layer circuit pattern is formed by etching portions of the copper plating 43 in correspondence to the circuit pattern (referring to FIG. 10).

(59) A stacked structure of the laser blocking layer 50 or the electromagnetic shielding layer 60 may be formed in various embodiments and will be described in detail in FIGS. 6a, 6b, 7a, and 7b.

(60) The laser blocking layer 50 or the electromagnetic shielding layer 60 may be extended to the rigid region R.

(61) The laser blocking layer 50 or the electromagnetic shielding layer 60 extended to the rigid region R is not removed by laser processing, and the via hole A or the through holes C and D formed in the rigid region R pass through some or all of the laser blocking layer 50 and the electromagnetic shielding layer 60.

(62) For example, as shown in FIG. 10, a second circuit pattern 23 formed on a fifth pattern layer 20 may be electrically grounded by being connected to the copper foil layer 63 of the electromagnetic shielding layer 60 through the via hole A.

(63) Further, the second circuit pattern 23 formed on the fifth pattern layer 20 may be connected to a second circuit pattern 23 formed on a third pattern layer 20 by passing through the electromagnetic shielding layer 60 and the laser blocking layer 50 through the through holes C and D.

(64) That is, the through holes C and D can ground the circuit patterns of the upper and lower pattern layers with respect to the base substrate 10.

(65) <Laser Blocking Layer>

(66) FIGS. 4a, 4b, and 5 are views showing various embodiments of a laser blocking layer.

First Embodiment

(67) As shown in FIG. 4a, a laser blocking layer 50 in accordance with a first embodiment of the present invention is formed in a three-layer structure including an adhesive 51, a polyimide layer 52, and a copper foil layer 53.

(68) The polyimide layer 52 is formed to protect a circuit pattern, and the polyimide layer 52 and the circuit pattern are formed while interposing the adhesive 51 therebetween, and the copper foil layer 53 is formed on the polyimide layer 52.

Second Embodiment

(69) As shown in FIG. 4b, a laser blocking layer 50 in accordance with a second embodiment of the present invention is formed in a four-layer structure including a first adhesive 51a, a second adhesive 51b, a polyimide layer 52, and a copper foil layer 53.

(70) It is possible to improve a stacked structure by interposing the first adhesive 51a and the second adhesive 51b between the polyimide layer 52 and the circuit pattern and between the polyimide layer 52 and the copper foil layer 53.

Third Embodiment

(71) As shown in FIG. 5, both ends of a copper foil layer 53 of a laser blocking layer 50 in accordance with a third embodiment of the present invention are formed shorter than both ends of a polyimide layer 52.

(72) That is, the both ends of the polyimide layer 52 of a flexible region F are extended to a rigid region R, and the copper foil layer 53 formed on the polyimide layer 52 is also extended to the rigid region R.

(73) The above method of forming the laser blocking layer 50 is just one embodiment, and the laser blocking layer 50 may be formed by various methods.

(74) <Electromagnetic Shielding Layer>

(75) FIGS. 6a, 6b, 7a, and 7b are views showing various embodiments of a stacked structure of a laser blocking layer and an electromagnetic shielding layer.

First Embodiment

(76) FIG. 6a is a view showing a stacked structure of a three-layer laser blocking layer 50 and a three-layer electromagnetic shielding layer 60, and FIG. 6b is a view showing a stacked structure of a four-layer laser blocking layer 50 and a four-layer electromagnetic shielding layer 60.

(77) The laser blocking layer 50 and the electromagnetic shielding layer 60 include adhesives 51 and 61, polyimide layers 52 and 62, and copper foil layers 53 and 63, respectively. The adhesive is disposed on at least one (referring to FIG. 6a) or both (referring to FIG. 6b) of upper and lower surfaces of the polyimide layers 52 and 62.

(78) That is, both of the laser blocking layer 50 and the electromagnetic shielding layer 60 are formed in three layers of the adhesives 51 and 61, the polyimide layers 52 and 62, and the copper foil layers 53 and 63 or in four layers of the first adhesives 51a and 61a, the polyimide layers 52 and 62, the second adhesives 51b and 61b, and the copper foil layers 53 and 63.

(79) Further, the laser blocking layer 50 may be formed in three layers, and the electromagnetic shielding layer 60 may be formed in four layers. Or, the laser blocking layer 50 may be formed in four layers, and the electromagnetic shielding layer 60 may be formed in three layers.

Second Embodiment

(80) FIG. 7a shows that a copper foil layer 63 of an electromagnetic shielding layer 60 is formed shorter than a polyimide layer 62 in a stacked structure of the laser blocking layer 50 and the electromagnetic shield layer 60 shown in FIG. 6a, and FIG. 7b shows that the copper foil layer 63 of the electromagnetic shielding layer 60 and a copper foil layer 53 of the laser blocking layer 50 are formed shorter than the polyimide layer 52 or 62 of the electromagnetic shielding layer 60 or the laser blocking layer 50.

(81) The above embodiment is just one embodiment of the present invention, and the stacked structure may be variously formed.

(82) The above method of forming the electromagnetic shielding layer 60 is just one embodiment, and the electromagnetic shielding layer 60 may be formed by various methods.

(83) Method for Manufacturing Multilayer Rigid Flexible Printed Circuit Board

(84) A method for manufacturing a multilayer rigid flexible printed circuit board in accordance with the present invention includes the steps of providing a base substrate, forming a laser blocking layer, stacking a plurality of pattern layers, and forming an outer pattern layer.

(85) FIGS. 8a to 8j are views showing a method for manufacturing a multilayer rigid flexible printed circuit board in accordance with an embodiment of the present invention.

(86) As shown in FIGS. 8a and 8b, in the step of providing a base substrate 10, a first circuit pattern 12 is formed by stacking a copper foil layer 12 on at least one surface of a flexible film 11 and etching the copper foil layer 12.

(87) As shown in FIG. 8c, a laser blocking layer 50 is completed by forming a polyimide layer 52 in a flexible region F of the base substrate 10 while interposing an adhesive 51 therebetween and forming a copper foil layer 53 on the polyimide layer 52.

(88) Further, the laser blocking layer 50 is completed by forming the polyimide layer 52 in the flexible region F of the base substrate 10 while interposing a first adhesive 51a therebetween and forming the copper foil layer 53 on the polyimide layer 52 while interposing a second adhesive 51b therebetween.

(89) At this time, each side surface of the copper foil layer formed on the adhesive may be formed smaller than the polyimide layer formed on a lower surface by 10 m.

(90) Further, the laser blocking layer 50 may be extended to a rigid region R from a boundary surface between the flexible region F and the rigid region R by 0.05 to 5 mm.

(91) As shown in FIGS. 8d to 8f, in the step of stacking a plurality of pattern layers 20 and 30, one pattern layer is formed by forming a copper foil layer 22 or 32 while interposing at least one insulator 21 or 31, forming via holes A and B or through holes C and D in portions of the insulator 21 or 31 or the copper foil layer 22 or 32, and forming a circuit pattern 23 or 33 after performing copper plating on the copper foil layer 22 or 32 having the via holes A and B or the through holes C and D formed therein, and the plurality of pattern layers are formed by repeating the above steps.

(92) As shown in FIGS. 8g to 8j, in the step of forming an outer pattern layer 40, an outer circuit pattern is formed by forming a copper foil layer 42 on the plurality of pattern layers 20 and 30 while interposing at least one insulator 41 therebetween, forming a via hole or a through hole, forming windows in the via hole or the through hole of the outer pattern layer 40 and the flexible region, and performing laser processing on the windows.

(93) Here, the method of forming the outer circuit pattern by forming the windows and performing the laser processing on the windows forms the outer circuit pattern by forming copper foil openings in the via hole or the through hole of the outer pattern layer and the flexible region through window etching, irradiating laser through the copper foil openings to remove the insulator, performing copper plating on the outer pattern layer from which the insulator is removed, and etching portions of the outer pattern layer.

(94) Further, a method for manufacturing a multilayer rigid flexible printed circuit board in another embodiment of the present invention can protect devices from external electromagnetic waves by providing a base substrate, forming a laser blocking layer, and further forming an electromagnetic shielding layer on the laser blocking layer.

(95) In an embodiment of the present invention, since the flexible region is manufactured without window processing by using materials and equipment of a rigid build-up substrate, it is possible to achieve process simplification and cost reduction and minimize scale change. Therefore, there is an effect of utilizing an existing rigid substrate production line without change.

(96) Further, since general prepreg can be used as the insulator used for manufacturing the rigid flexible printed circuit board instead of no flow prepreg, there are effects of improving filling performance and reducing cost.

(97) Further, since the electromagnetic shielding layer is further provided, there is an effect of minimizing influence of external electromagnetic waves.

(98) Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.