Circuit board and manufacturing method thereof

Abstract

A circuit board including a substrate, a patterned conductive layer, a patterned insulating layer, a conductive terminal, and a dummy terminal is provided. The patterned conductive layer is disposed on the substrate. The patterned insulating layer is disposed on the substrate and at least covers a portion of the patterned conductive layer. The conductive terminal is disposed on the patterned conductive layer and has a first top surface. The dummy terminal is disposed on the patterned conductive layer and has a second top surface. A first height between the first top surface and the substrate is greater than a second height between the second top surface and the substrate.

Claims

1. A circuit board comprising: a substrate; a patterned conductive layer disposed on the substrate; a patterned insulating layer disposed on the substrate and at least covering a portion of the patterned conductive layer, the patterned insulating layer has a third top surface; a conductive terminal disposed on the patterned conductive layer and having a first top surface; and a dummy terminal disposed on the patterned conductive layer and having a second top surface, wherein a first height between the first top surface and the substrate is greater than a second height between the second top surface and the substrate, and the first height between the first top surface and the substrate is greater than a third height between the third top surface and the substrate, wherein the patterned insulating layer has an insulating opening, and the dummy terminal is embedded in the insulating opening, wherein the dummy terminal comprises a plating seed layer and a plating layer, the plating layer is disposed on the plating seed layer and physically separated from the patterned insulating layer, wherein the plating seed layer covers a bottom surface of the insulating opening and a side wall of the insulating opening, another plating layer disposed under the plating seed layer has a mesh pattern, and top and side surfaces of the mesh pattern are covered by the plating seed layer.

2. The circuit board of claim 1, wherein the conductive terminal and the dummy terminal are electrically separated from each other.

3. The circuit board of claim 1, wherein: the substrate has a first surface; the patterned conductive layer is disposed on the first surface of the substrate; and a ratio of a sum of a projected area of the conductive terminal on the first surface and a projected area of the dummy terminal on the first surface to a surface area of the first surface is greater than or equal to 10% and less than 100%.

4. The circuit board of claim 3, wherein a ratio of the projected area of the conductive terminal on the first surface to the surface area of the first surface is greater than or equal to 1% and less than or equal to 5%.

5. The circuit board of claim 1, wherein: the third height between the third top surface and the substrate is greater than the second height between the second top surface and the substrate.

6. The circuit board of claim 1, wherein: the substrate has a first surface; the patterned conductive layer is disposed on the first surface of the substrate; and a projected area of the conductive terminal on the first surface is smaller than a projected area of the dummy terminal on the first surface.

7. The circuit board of claim 1, wherein a maximum thickness of the dummy terminal is greater than a thickness of the patterned conductive layer.

8. The circuit board of claim 7, wherein a surface roughness of the first top surface is smaller than a surface roughness of the second top surface.

9. The circuit board of claim 1, wherein a surface roughness of the first top surface is substantially equal to a surface roughness of the second top surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.

(2) FIG. 1A to FIG. 1G are cross-sectional views of a manufacturing method of a circuit board according to a first embodiment of the invention.

(3) FIG. 1H is a top view of a manufacturing method of a circuit board according to a first embodiment of the invention.

(4) FIG. 1I is a top view of a manufacturing method of a circuit board according to a first embodiment of the invention.

(5) FIG. 2A to FIG. 2B are cross-sectional views of a manufacturing method of a circuit board according to a second embodiment of the invention.

(6) FIG. 2C is a top view of a manufacturing method of a circuit board according to a second embodiment of the invention.

(7) FIG. 3A to FIG. 3C are cross-sectional views of a manufacturing method of a circuit board according to a third embodiment of the invention.

(8) FIG. 3D is a top view of a manufacturing method of a circuit board according to a third embodiment of the invention.

DESCRIPTION OF THE EMBODIMENTS

(9) In this regard, directional terminology, such as “up,” “top”, “bottom”, etc., is used with reference to the orientation of the Figure(s) being described. As such, the directional terminology is used for purposes of illustration and is in no way limiting.

(10) In the detailed description of the embodiments, the terms “first”, “second”, “third” and the like may be used to describe different elements. These terms are only used to distinguish elements from each other, but in the structure, these elements may not be limited by these terms. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the inventive concept. In addition, in the manufacturing method, the formation of these elements or components may not be limited by these terms except for a specific process flow. For example, the first element may be formed before the second element. Or, the first element may be formed after the second element. Alternatively, the first element and the second element may be formed in the same process or step.

(11) The thickness of layer(s) or region(s) in the drawings may be exaggerated for clarity. The same or similar reference numerals may indicate the same or similar elements, and have the same or similar materials, formation manners or configurations, and the following descriptions will not be repeated.

(12) FIG. 1A to FIG. 1G are cross-sectional views of a manufacturing method of a circuit board according to a first embodiment of the invention. FIG. 1H is a top view of a manufacturing method of a circuit board according to a first embodiment of the invention. FIG. 1I is a top view of a manufacturing method of a circuit board according to a first embodiment of the invention. For example, FIG. 1H may be a top view corresponding to the structure in FIG. 1B, and FIG. 1I may be a top view corresponding to the structure in FIG. 1F. Further, a part of the film layer or element may be omitted in FIG. 1A to FIG. 1I for clarity.

(13) Referring to FIG. 1A, a substrate 110 is provided. The material of the substrate 110 is not limited in the present invention. For example, the substrate 110 may be a rigid substrate adapted to support a film layer or element formed thereon in a subsequent process. For another example, the substrate 110 may be a flexible substrate, and the aforementioned flexible substrate may be disposed on a carrier (not shown).

(14) Referring to FIG. 1A, a patterned conductive layer 120 is formed on the first surface 110a of the substrate 110. The conductive material and the manner of forming the patterned conductive layer 120 are not limited in the present invention.

(15) In the embodiment, other layer(s), elements(s), or device(s) may be disposed between the patterned conductive layer 120 and the substrate 110 depending on the design or requirement. For example, a release layer 191 may be disposed on the first surface 110a of the substrate 110, and the circuit layer may be disposed on the release layer 191. An insulating layer 193 may be disposed between the circuit layer 192 and the patterned conductive layer 120. A portion of the circuit layer 192 and a portion of the patterned conductive layer 120 may be electrically connected to each other through a corresponding conductive via 194. The conductive via 194 and the patterned conductive layer 120 may be formed by the same or similar processes, but the invention is not limited thereto.

(16) In the embodiment, the patterned conductive layer 120 may include a contact area 121, a dummy plating area 122, and a circuit area 123. The circuit area 123 is connected to the contact area 121, and the dummy plating area 122 and the contact area 121 are separated from each other.

(17) In an embodiment, the contact area 121 may be electrically separate the dummy plating area 122.

(18) Referring to FIG. 1B and FIG. 1H, after forming the patterned conductive layer 120, the patterned insulating layer 130 is formed on the first surface 110a of the substrate 110. The patterned insulating layer 130 covers a portion of the patterned conductive layer 120. For example, the patterned insulating layer 130 may cover the circuit area 123 of the patterned conductive layer 120. The patterned insulating layer 130 has a first insulating opening 131 and a second insulating opening 132. The first insulating opening 131 may expose the contact area 121 of the patterned conductive layer 120, and the second insulating opening 132 may expose the dummy plating area 122 of the patterned conductive layer 120. In addition, the patterned insulating layer 130 may be a single-layer insulating structure or a multilayer insulating structure, and the insulating material and the manner of forming the patterned insulating layer 130 are not limited in the invention.

(19) In the embodiment, the dummy plating area 122 includes a plurality of strip structures 122a, but the invention is not limited thereto.

(20) Referring to FIG. 1C, after forming the patterned insulating layer 130, a plating seed layer 140 is formed on the first surface 110a of the substrate 110. The plating seed layer 140 may be disposed on the patterned insulating layer 130 and a portion of the patterned conductive layer 120 that is not covered by the patterned insulating layer 130. For example, the plating seed layer 140 may cover the patterned insulating layer 130, the contact area 121 of the patterned conductive layer 120, and the dummy plating area 122 of the patterned conductive layer 120. That is, the plating seed layer 140 may be conformally covered on the patterned insulating layer 130 and a portion of the patterned conductive layer 120 that is not covered by the patterned insulating layer 130. In this way, the contact area 121 and the plating seed layer 122 may be electrically connected to each other by the plating seed layer 140. In addition, the plating seed layer 140 may be a single-layer conductive structure or a multilayer conductive structure, and the conductive material and the manner of forming the plating seed layer 140 are not limited in the invention.

(21) Referring to FIG. 1D, after forming the plating seed layer 140, a plating mask layer 150 is formed on the plating seed layer 140. The plating mask layer 150 is disposed on a portion of the plating seed layer 140. The plating mask layer 150 has a plating opening 151 and a dummy plating opening 152, the plating opening 151 is disposed corresponding to the contact area 121, and the dummy plating opening 152 is disposed corresponding to the plating area 122. In addition, the material and the manner of forming the plating mask layer 150 are not limited in the present invention.

(22) For example, the plating seed layer 140 includes a first seed portion 141, a second seed portion 142, and a third seed portion 143. The first seed portion 141 is disposed at least corresponding to the contact area 121 of the patterned conductive layer 120. The second seed portion 142 is disposed at least corresponding to the dummy plating area 122 of the patterned conductive layer 120. The third seed portion 143 is disposed corresponding to the circuit area 123 of the patterned conductive layer 120. The plating mask layer 150 is disposed on the third seed portion 143 of the plating seed layer 140. The plating opening 151 of the plating mask layer 150 exposes the first seed portion 141 of the plating seed layer 140. The dummy plating opening 152 of the plating mask layer 150 exposes the second seed portion 142 of the plating seed layer 140.

(23) In the embodiment, the ratio of the sum of the opening area of the plating opening 151 and the opening area of the dummy plating opening 152 to the surface area of the first surface 110a is greater than or equal to 10% and less than 100%. As such, in the subsequent electroplating process, the possibility of flash plating or skip plating may be reduced.

(24) In the embodiment, the ratio of the opening area of the plating opening 151 to the surface area of the first surface 110a is greater than or equal to 1% and less than or equal to 5%. In general, the position or area of the plating opening 151 is configured in accordance with the specifications of the product. Therefore, in the subsequent electroplating process, the entire plating area may be increased by the dummy plating opening 152, and the possibility of flash plating or skip plating within the plating opening 151 may be reduced.

(25) Referring to FIG. 1E, after forming the plating mask layer 150, a plating layer 160 is formed in the plating opening 151 and the dummy plating opening 152. The plating layer 160 includes a first plating portion 161 and a second plating portion 162. The first plating portion 161 is disposed within the plating opening 151, and the second plating portion 162 is disposed within the dummy plating opening 152. The plating layer 160 is formed by an electroplating process, and the plating layer 160 may be a single-layer conductive structure or a multilayer conductive structure. For example, the substrate 110 and the structure thereon (e.g., as shown in FIG. 1D) may be immersed in a plating solution (not shown), and then a plating electrode (not shown) may be electrically connected to the plating seed layer 140 and energized. The plating layer 160 is electroplated on a portion of the plating seed layer 140 that is not covered by the plating mask layer 150.

(26) In the embodiment, the opening area of the plating opening 151 may be smaller than the opening area of the dummy plating opening 152. In this way, the height of the first plating portion 161 can be made larger than the height of the second plating portion 162.

(27) Referring to FIG. 1F, after forming the plating layer 160, the plating mask layer 150 (shown in FIG. 1E) and a portion of the plating seed layer 140 (shown in FIG. 1E) are removed, and a conductive terminal 181 corresponding to the contact area 121 and a dummy terminal 182 corresponding to the dummy plating area 122 may be formed.

(28) For example, the plating mask layer 150 may be removed first to expose the third seed portion 143 of the plating seed layer 140 (shown in FIG. 1E). The plating mask layer 150 may be removed by a suitable process (e.g., ashing process or etching process) depending on the material of the plating mask layer 150, but the invention is not limited thereto.

(29) Then, after exposing the third seed portion 143 of the plating seed layer 140, the plating layer 160 (shown in FIG. 1E) may be used as a mask to remove the third seed portion 143 of the plating seed layer 140. The third seed portion 143 of the plating seed layer 140 may be removed by a suitable process (e.g., etching process) depending on the material of the plating seed layer 140, but the invention is not limited thereto.

(30) In an embodiment, after removing the third seed portion 143 of the plating seed layer 140, the first seed portion 141 of the plating seed layer 140 and the first plating portion 161 of the plating layer 160 may be electrically separated from the second seed portion 142 of the plating seed layer 140 and the second plating portion 162 of the plating layer 160.

(31) In an embodiment, in the step of removing the third seed portion 143 of the plating seed layer 140, a portion of the plating layer 160, a portion of the first seed portion 141 of the plating seed layer 140, and/or a second seed portion 142 of the plating seed layer 140 may further be removed slightly. For example, in a wet etching or other similar anisotropic etching process, a portion of the plating layer 160, a portion of the first seed portion 141 of the plating seed layer 140, and/or a second seed portion 142 of the plating seed layer 140 may further be removed slightly.

(32) After removing the third seed portion 143 of the plating seed layer 140, the first seed portion 141 and the first plating portion 161 may constitute the conductive terminal 181; and the second seed portion 142 and the second plating portion 162 may constitute the dummy terminal 182. That is, the conductive terminal 181 at least includes the first seed portion 141 and the first plating portion 161; and the dummy terminal 182 at least includes the second seed portion 142 and the second plating portion 162.

(33) Referring to FIG. 1G, in an embodiment, after removing the third seed portion 143 of the plating seed layer 140 (shown in FIG. 1E), a conductive protective layer 171 may be formed on the first seed portion 141 and the first plating portion 161, and a conductive protective layer 172 may be formed on the second seed portion 142 and the second plating portion 162. The conductive protective layers 171 and 172 are, for example, an electroless nickel electroless palladium immersion gold (ENEPIG) layer, but the invention is not limited thereto. The conductive protective layer 171 may enhance the bonding of the conductive terminals 181 with other electronic components. The conductive protective layers 171 and 172 may reduce damage (e.g., oxidation) of the first seed portion 141, the first plating portion 161, the second seed portion 142, and the second plating portion 162. In other words, the first seed portion 141, the first plating portion 161, and the conductive protective layer 171 (if any) may constitute the conductive terminal 181; and the second seed portion 142, the second plating portion 162, and the conductive protective layer 172 (if any) may constitute the dummy terminal 182. That is, the conductive terminal 181 may include the first seed portion 141, the first plating portion 161, and the conductive protective layer 171 (if any); and the dummy terminal 182 may include the second seed portion 142, the second plating portion 162, and the conductive protective layer 172 (if any).

(34) Referring to FIG. 1G and FIG. 1I, after the above manufacturing process is performed, a circuit board 100 provided in the present embodiment is substantially formed. The circuit board 100 includes a substrate 110, a patterned conductive layer 120, a patterned insulating layer 130, at least one conductive terminal 181, and at least one dummy terminal 182. The patterned conductive layer 120 is disposed on the substrate 110. The patterned insulating layer 130 is disposed on the substrate 110 and at least covers a portion of the patterned conductive layer 120. The conductive terminal 181 is disposed on the patterned conductive layer 120. The dummy terminal 182 is disposed on the patterned conductive layer 120. The conductive terminal 181 has a first top surface 181a (e.g., a surface of the conductive terminal 181 that is furthest from the first surface 110a of the substrate 110). The first top surface 181a and the substrate 110 have a first height 181h therebetween. The dummy terminal 182 has a second top surface 182a (e.g., a surface of the dummy terminal 182 that is furthest from the first surface 110a of the substrate 110). The second top surface 182a and the substrate 110 have a second height 182h therebetween. The first height 181h is greater than the second height 182h. In this way, when the other electronic component(s) (e.g., a chip) is/are bonded to the circuit board 100 (e.g., a chip is bonded to the circuit board 100 by flip-chip bonding), the possibility that the aforementioned electronic component touches the dummy terminal 182 may be reduced.

(35) In the embodiment, the number of conductive terminals 181 and/or the number of dummy terminals 182 is not limited.

(36) In terms of process, the projected area of the conductive terminal 181 on the first surface 110a is substantially the same or similar to the opening area of the plating opening 151 (shown in FIG. 1E) of the plating mask layer 150 (shown in FIG. 1E); and the projected area of the dummy terminal 182 on the first surface 110a is substantially the same or similar to the open area of the dummy plating opening 152 (shown in FIG. 1E) of the plating mask layer 150. That is, the ratio of the sum of the projected area of the conductive terminal 181 on the first surface 110a and the projected area of the dummy terminal 182 on the first surface 110a to the surface area of the first surface 110a is substantially greater than or equal to 10% and less than 100%. That is, the ratio of the projected area of the conductive terminal 181 on the first surface 110a to the surface area of the first surface 110a is substantially greater than or equal to 1% and less than or equal to 5%.

(37) In the embodiment, the projected area of the conductive terminal 181 on the first surface 110a is smaller than the projected area of the dummy terminal 182 on the first surface 110a.

(38) In the embodiment, the conductive terminal 181 may be electrically separated from the dummy terminal 182 from each other, but the invention is not limited thereto. In an embodiment, the dummy terminal 182 of the circuit board 100 may be an isolated electrical conductor. That is, in an embodiment, the dummy terminal 182 may not be electrically connected to other electrical conductors, and the plurality of dummy terminals 182 are not electrically connected to each other.

(39) In the embodiment, the patterned insulating layer 130 has a third top surface 130a, the third top surface 130a and the substrate 110 have a third height 130h therebetween, and the third height 130h is greater than the second height 182h, but the invention is not limited thereto.

(40) In the embodiment, the maximum thickness 182t of the dummy terminal 182 is greater than the thickness 120t of the patterned conductive layer 120, but the invention is not limited thereto.

(41) In the embodiment, the surface roughness of the first top surface 181a is smaller than the surface roughness of the second top surface 182a, but the invention is not limited thereto.

(42) FIG. 2A to FIG. 2B are cross-sectional views of a manufacturing method of a circuit board according to a second embodiment of the invention. FIG. 2C is a top view of a manufacturing method of a circuit board according to a second embodiment of the invention. For example, FIG. 2C may be a top view corresponding to the structure in FIG. 2A. Further, a part of the film layer or element may be omitted in FIG. 2A to FIG. 2C for clarity.

(43) Referring to FIG. 2A and FIG. 1A, a patterned conductive layer 220 is formed on the substrate 110 similar to the step illustrated in FIG. 1A. The patterned conductive layer 220 may include a contact area 121, a dummy plating area 222, and a circuit area 123. The circuit area 123 is connected to the contact area 121, and the dummy plating area 222 and the contact area 121 are separated from each other.

(44) Referring to FIGS. 2A, 2C and 1B, after forming the patterned conductive layer 220, the patterned insulating layer 130 is formed on the first surface 110a of the substrate 110. The patterned insulating layer 130 covers a portion of the patterned conductive layer 220. For example, the patterned insulating layer 130 may cover the circuit area 123 of the patterned conductive layer 220. The first insulating opening 131 may expose the contact area 121 of the patterned conductive layer 220, and the second insulating opening 132 may expose the dummy plating area 222 of the patterned conductive layer 220.

(45) The patterned conductive layer 220 of the present embodiment is similar to the patterned conductive layer 120 of the first embodiment, with the difference that the dummy plating area 222 includes a plurality of block structures 222b.

(46) Referring to FIG. 2A to FIG. 2B and FIG. 1B to FIG. 1G, after forming the patterned conductive layer 220, the fabrication of the circuit board 200 of the embodiment may be substantially provided by steps similar to those illustrated in FIG. 1B to FIG. 1G.

(47) The circuit board 200 of the present embodiment is similar to the circuit board 100 of the first embodiment. In the embodiment, the dummy terminal 282 may include a second seed portion 242, a second plating portion 262, and a conductive protective layer 272 (if any). Compared with the circuit board 100 of the first embodiment, the surface roughness of the second top surface 282a of the dummy terminal 282 of the circuit board 200 may be smaller than the surface roughness of the second top surface 182a of the dummy terminal 182 of the circuit board 100.

(48) In the embodiment, the surface roughness of the first top surface 181a is smaller than the surface roughness of the second top surface 282a, but the invention is not limited thereto.

(49) FIG. 3A to FIG. 3C are cross-sectional views of a manufacturing method of a circuit board according to a third embodiment of the invention. FIG. 3D is a top view of a manufacturing method of a circuit board according to a third embodiment of the invention. For example, FIG. 3D may be a top view corresponding to the structure in FIG. 3B. Further, a part of the film layer or element may be omitted in FIG. 3A to FIG. 3D for clarity.

(50) Referring to FIG. 3A, a patterned conductive layer 320 is formed on the first surface 110a of the substrate 110 similar to the step of FIG. 1A. The patterned conductive layer 320 may include a contact area 121 and a circuit area 123.

(51) Referring to FIGS. 3A, 3D and 1B, after forming the patterned conductive layer 320, the patterned insulating layer 130 is formed on the first surface 110a of the substrate 110 similar to the step of FIG. 1B. The patterned insulating layer 130 covers a portion of the patterned conductive layer 320. For example, the patterned insulating layer 130 may cover the circuit area 123 of the patterned conductive layer 320. The first insulating opening 131 may expose the contact area 121 of the patterned conductive layer 320, and no conductive layer (e.g., the patterned conductive layer 320) may be exposed within the opening area of the second insulating opening 132.

(52) Referring to FIG. 3B to FIG. 3C and FIG. 1B to FIG. 1G, after forming the patterned insulating layer 130, the fabrication of the circuit board 300 of the embodiment may be substantially provided by steps similar to those illustrated in FIG. 1B to FIG. 1G. For example, in a step similar to FIG. 1D, the opening area of the dummy plating opening 152 (shown in FIG. 1D) may not be overlapped with the patterned conductive layer 320. As such, the formed dummy terminals 382 may not overlap the patterned conductive layer 320.

(53) The circuit board 300 of the present embodiment is similar to the circuit board 100 of the first embodiment. In the embodiment, the dummy terminal 382 may include a second seed portion 342, a second plating portion 362, and a conductive protective layer 372 (if any). Compared with the circuit board 100 of the first embodiment, the surface roughness of the second top surface 382a of the dummy terminal 382 of the circuit board 300 may be smaller than the surface roughness of the second top surface 182a of the dummy terminal 182 of the circuit board 100.

(54) In the embodiment, the surface roughness of the first top surface 181a may be substantially equal to the surface roughness of the second top surface 382a.

(55) In summary, in the manufacturing method of a circuit board of the present invention, the plating area in an electroplating process may be improved by a dummy plating opening. As such, in the electroplating process, the possibility of flash plating or skip plating may be reduced, and the yield or quality of the circuit board may be improved.

(56) It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.