TWI912155B - Circuit board and method for fabricating the same - Google Patents

Abstract

A circuit board and a method for fabricating the same are provided. The circuit board includes two wire boards. The wire boards are opposite to each other, and a spacing layer is located between the wire boards. Each wire board includes a circuit layer and a magnetic material layer disposed on the circuit layer. The magnetic material layer has a first magnetic pole and a second magnetic pole. The first magnetic pole is located between the circuit layer and the second magnetic pole, and the magnetic material layer of one of the wire boards faces to the magnetic material layer of the other one of the wire boards. A repulsive force is formed between the second magnetic poles of the magnetic material layers.

Description

Circuit board and its manufacturing method

This invention relates to a circuit board, and more particularly to a multilayer circuit board.

Modern multilayer circuit boards typically have four or more layers, with each layer connected structurally and electrically via adhesive layers and conductive copper layers. However, this structural limitation prevents relative displacement between layers. In the trend towards multifunctional terminal electronic products, this structure will significantly restrict the application of multilayer board functions.

Therefore, the present invention provides a circuit board for realizing relative displacement between two adjacent layers in the circuit board.

At least one embodiment of the present invention also provides a method for manufacturing the aforementioned circuit board.

At least one embodiment of the present invention provides a circuit board comprising two circuit substrates. The circuit substrates are disposed opposite to each other, and a gap layer is provided between the circuit substrates. Each circuit substrate includes a circuit layer and a magnetic material layer disposed on the circuit layer, and the magnetic material layer has a first magnetic pole and a second magnetic pole with opposite polarities. The first magnetic pole is located between the circuit layer and the second magnetic pole, and the magnetic material layer of one circuit substrate faces the magnetic material layer of the other circuit substrate, while a repulsive force is formed between the second magnetic pole of one magnetic material layer and the second magnetic pole of the other magnetic material layer.

This invention also provides a method for manufacturing a circuit board, comprising providing an insulating substrate; forming a conductive layer on the insulating substrate; forming a first magnetic material layer on the conductive layer, wherein the first magnetic material layer has a first magnetic pole and a second magnetic pole with opposite polarities, the first magnetic pole being located between the conductive layer and the second magnetic pole; forming a removable material on the first magnetic material layer, wherein the first magnetic material layer is located between the conductive layer and the removable material; A second magnetic material layer is formed on the removable material, with the removable material located between the second magnetic material layer and the first magnetic material layer; a first circuit layer is formed on the second magnetic material layer, with the second magnetic material layer located between the first circuit layer and the removable material; after forming the first circuit layer, multiple flexible conductive structures are formed in the first magnetic material layer, the removable material, and the second magnetic material layer, and the flexible conductive structures are electrically connected to the conductive layers.

Based on the above, at least one embodiment of the present invention provides a repulsive force through opposite magnetic poles in the magnetic material layer, preventing the two circuit substrates from directly contacting each other, but connecting (including electrical connection) the two circuit substrates through a flexible connection structure. In this way, without affecting the electrical connection between the two circuit substrates, displacement or deformation of one circuit substrate due to external force will not drive the other circuit substrate, thereby providing the feasibility of relative displacement of internal components (e.g., circuit substrates) of the circuit board.

This invention will be described in detail with reference to the following embodiments. It should be noted that the descriptions of the embodiments below are for illustrative purposes only and are not intended to reveal all embodiments exhaustively or to limit the specific embodiments of the invention. For example, the phrase "the first feature is formed on the second feature" includes multiple embodiments, covering situations where the first and second features are in direct contact, and situations where additional features are formed between the first and second features so that they are not in direct contact. Furthermore, the same element symbols used in the drawings and specifications will, to the extent possible, represent the same or similar elements.

Spatially relative terms, such as "lower," "below," "below," "above," and "above," are used here to briefly describe the relationship between one component or feature as shown in the diagram and another component or feature. These spatially relative terms cover not only the rotation depicted in the diagram but also different rotations during the use or operation of the device. Furthermore, when the component can be rotated (rotated 90 degrees or other angles), the spatially relative descriptive terms used here can also be interpreted accordingly.

Furthermore, when using terms such as "approximately" or "about" to describe a number or a range of numbers, the term is intended to cover a reasonable range of numbers and must take into account the natural differences that a person skilled in the art would understand during the manufacturing process. A range of numbers covers a reasonable range including the number being described; for example, within +/-10% of the described number is based on known manufacturing tolerances that relate to the characteristics of the manufacturing feature. For instance, a material layer with a thickness of "approximately 5 nanometers" can cover a size range from 4.25 nanometers to 5.75 nanometers, where a manufacturing tolerance of +/-15% for depositing that material layer is known to a person skilled in the art. Furthermore, this invention may repeat reference numerals and/or designations in various examples. This repetition is for simplification and clarity, and is not intended to indicate the relationship between the various implementation methods and/or configurations discussed herein.

This invention provides a circuit board 100. Referring to FIG1, the circuit board 100 includes a circuit substrate 110 and a circuit substrate 120, and a flexible connection structure 130. The circuit substrate 110 and the circuit substrate 120 are disposed opposite to each other, and a gap layer 150 is provided between the circuit substrate 110 and the circuit substrate 120. Each circuit substrate includes a circuit layer and a magnetic material layer. Specifically, the circuit substrate 110 includes a circuit layer 112 and a magnetic material layer 114, while the circuit substrate 120 includes a circuit layer 122 and a magnetic material layer 124.

A magnetic material layer 114 is disposed on the circuit layer 112, and the magnetic material layer 114 has a first magnetic pole 114S and a second magnetic pole 114N with opposite polarities. On the other hand, a magnetic material layer 124 is disposed on the circuit layer 122, and the magnetic material layer 124 also has a first magnetic pole 124S and a second magnetic pole 124N with opposite polarities. The first magnetic pole 114S is located between the circuit layer 112 and the second magnetic pole 114N, while the first magnetic pole 124S is located between the circuit layer 122 and the second magnetic pole 124N.

It is worth mentioning that the magnetic material layer 114 of the circuit substrate 110 faces the magnetic material layer 124 of the circuit substrate 120. In other words, the magnetic material layers 114 and 124 are located between the circuit layers 112 and 122, and the second magnetic pole 114N of the magnetic material layer 114 faces the second magnetic pole 124N of the magnetic material layer 124. Since the magnetism of the first magnetic poles 114S and 124S is opposite to that of the second magnetic poles 114N and 124N, a repulsive force RF1 is formed between the second magnetic poles 114N and 124N.

Magnetic material layers 114 and 124 may contain magnetic thin film material, which may be a strongly magnetic material with a thickness of less than 1µm. For example, it may contain ferromagnetic or ferrimagnetic materials such as ferrite thin film material, wherein the ferrite thin film material may be a thin film formed by iron, oxygen and other metallic elements (e.g., zinc, nickel, manganese, cobalt, etc.) through a specific process.

In addition, the circuit substrate 110 also includes a conductive layer 115, an insulating substrate 116, and a bonding layer 118. The conductive layer 115 is disposed between the magnetic material layer 114 and the circuit layer 112, the insulating substrate 116 is disposed between the circuit layer 112 and the conductive layer 115, and the bonding layer 118 is disposed between the insulating substrate 116 and the magnetic material layer 114. On the other hand, the circuit substrate 120 includes a bonding layer 128, which is disposed on the circuit layer 122, and the circuit layer 122 is located between the magnetic material layer 124 and the bonding layer 128.

In this embodiment, the conductive layer 115 of the circuit substrate 110 may comprise copper or a similar metallic material. The insulating substrate 116 may comprise, for example, polyimide (PI) or a similar insulating material. The bonding layer 118 and bonding layer 128 may comprise, for example, epoxy resin or a similar insulating bonding material.

A flexible connection structure 130 is disposed between and connects the circuit substrate 110 and the circuit substrate 120. The circuit substrate 110 is electrically connected to the circuit substrate 120 through the flexible connection structure 130. Specifically, the two ends of the flexible connection structure 130 are respectively connected to the circuit layer 112 of the circuit substrate 110 and the circuit layer 122 of the circuit substrate 120, so as to form an electrical connection between the circuit layer 112 and the circuit layer 122.

A flexible connection structure 130 is distributed in the gap layer 150, and the flexible connection structure 130 further includes a conductive material 135 and a bonding layer 138. The conductive material 135 connects the circuit substrate 110 and the circuit substrate 120, and the circuit layer 112 of the circuit substrate 110 is connected to the circuit layer 122 of the circuit substrate 120 through the conductive material 135. The bonding layer 138 covers the outer surface 135s of the conductive material 135 and completely covers the outer surface 135s to isolate the conductive material 135 from the gap layer 150. The conductive material 135 may contain copper or a similar metal material, while the bonding layer 138 may contain epoxy resin or a similar insulating bonding material.

In this embodiment, the circuit board 100 further includes an electronic component 160 and a flexible conductive structure 170. The electronic component 160 is disposed on a circuit substrate 120, and the circuit substrate 120 is located between the electronic component 160 and the circuit substrate 110. More specifically, the electronic component 160 is disposed on a bonding layer 128 of the circuit substrate 120, wherein the bonding layer 128 is located between the electronic component 160 and the circuit layer 122.

A flexible conductive structure 170 is disposed between the circuit substrate 110 and the electronic component 160. As shown in FIG1, the flexible conductive structure 170 extends from the circuit substrate 120 through the gap layer 150 and to the conductive layer 115 in the circuit substrate 110, and the electronic component 160 is electrically connected to the circuit substrate 110 (and/or the circuit substrate 120) through the flexible conductive structure 170.

Notably, the circuit board 100 also includes multiple pads 102 and multiple solder materials (not shown). The pads 102 are disposed between the bonding layer 128 of the circuit board 120 and the electronic components 160, while the solder materials are disposed between the pads 102 and the electronic components 160. The electronic components 160 can be connected to the pads 102 via the solder materials and, in turn, to the flexible conductive structure 170 via the pads 102. That is, the electronic components 160 can be electrically connected to the flexible conductive structure 170 via the solder materials and the pads 102.

Referring to Figure 2, in another embodiment, the circuit board 100 may further include an electronic component 180. The electronic component 180 is disposed on and electrically connected to the circuit substrate 110. The circuit substrate 110 is located between the electronic component 160 and the electronic component 180. The electronic component 160 and the electronic component 180 can be active components such as transistors, or passive components such as capacitors and inductors. Furthermore, in other embodiments, the electronic component 160 may also be electrically connected to the circuit substrate 120 by means such as wire bonding.

Referring back to Figure 1, circuit substrates 110 and 120 also include multiple vias TH1 and TH2. These vias are distributed within the circuit layers and magnetic material layers, connecting opposite sides of the circuit substrates. Specifically, via TH1 is located within circuit layer 112 and magnetic material layer 114, connecting opposite sides of circuit substrate 110, while via TH2 is located within circuit layer 122 and magnetic material layer 124, connecting opposite sides of circuit substrate 120. Vias TH1 and TH2 can release stress on circuit substrates 110 and 120 during relative displacement, reducing the likelihood of damage to circuit substrates 110 and 120.

As shown in Figure 1, the circuit board 100 further includes a cover layer 190. This cover layer 190 is disposed on the circuit substrate 110. The circuit substrate 110 is located between the cover layer 190 and the circuit substrate 120, and the cover layer 190 covers the circuit layer 112 of the circuit substrate 110. The cover layer 190 can be a coverlay (CVL). In addition, the circuit board 100 also includes a protective layer 104, which is disposed on the cover layer 190, and the cover layer 190 is located between the protective layer 104 and the circuit substrate 110.

Please refer to Figures 3A and 3B together, which illustrate a schematic diagram of a circuit board according to at least one embodiment of the present invention applied to an electronic module. As shown in Figure 3A, the electronic module 30 includes a circuit board 100, a first module element 301, and a second module element 302. The first module element 301 and the second module element 302 are respectively disposed on opposite sides of the circuit board 100. Specifically, the first module element 301 is disposed on a circuit substrate 110, and the second module element 302 is disposed on a circuit substrate 120. The circuit substrates 110 and 120 are located between the first module element 301 and the second module element 302.

In this embodiment, the first module element 301 may include a camera lens, such as a complementary metal-oxide-semiconductor (CMOS) camera lens or a similar element, and is electrically connected to the circuit board 120. On the other hand, the second module element 302 may include a camera lens base plate and is electrically connected to the circuit board 110.

When the electronic module 30 is subjected to an external force F1, such as vibration or swaying, the first module element 301 will displace accordingly. Since the first module element 301 and the second module element 302 are connected to each other through a flexible connection structure 130, the flexible connection structure 130 will deform. Thus, the second module element 302 will not be displaced or deformed by the first force. In other words, although the flexible connection structure 130 provides a connection (electrical connection) between the first module element 301 and the second module element 302, it does not affect the independence of the displacement of the first module element 301 and the second module element 302.

At least one embodiment of the present invention provides a method for manufacturing a circuit board. Taking circuit board 100 as an example, this method may include several steps as shown in Figures 4A to 4E. Referring to Figure 4A, firstly, an insulating substrate 116 is provided. Next, a conductive layer 115 can be formed on the insulating substrate 116 by means of, for example, electroplating, photolithography, and etching. After forming the conductive layer 115, a magnetic material layer 114 can be formed on the conductive layer 115 by means of, for example, hot pressing. The magnetic material layer 114 has a first magnetic pole 114S and a second magnetic pole 114N with opposite polarities. As shown in Figure 4A, the first magnetic pole 114S is located between the conductive layer 115 and the second magnetic pole 114N.

Referring to Figure 4B, a removable material 405 is formed on the magnetic material layer 114. The magnetic material layer 114 is located between the conductive layer 115 and the removable material 405. The removable material 405 may contain, for example, polyvinyl carbonate (e.g., QPAC) or a similar material, and can be removed by, for example, thermal decomposition.

Next, a magnetic material layer 124 can be formed on the removable material 405 by means such as hot pressing. The removable material 405 is located between the magnetic material layer 124 and the magnetic material layer 114. Next, a circuit layer 122 can be formed on the magnetic material layer 124 by means such as sputtering, photolithography, and etching. The magnetic material layer 124 is located between the circuit layer 122 and the removable material 405.

Referring to Figure 4C, after forming the circuit layer 122, multiple flexible conductive structures 170 are formed in the magnetic material layer 114, the removable material 405, and the magnetic material layer 124, and these flexible conductive structures 170 are electrically connected to the conductive layer 115. Notably, the flexible conductive structures 170 are formed by first removing a portion of the magnetic material layer 114, the removable material 405, and the second magnetic material layer 124 by laser to form multiple openings (not shown).

Next, insulating material 407 is filled into the opening, completely covering the inner wall of the opening. After filling the opening with insulating material 407, a portion of the insulating material 407 can be removed by means such as laser drilling to form multiple secondary openings (not shown) within the insulating material 407, exposing the conductive layer 115. After forming the secondary openings, a conductive material 409 can be filled into the secondary openings by means such as electroplating, and the conductive material 409 is electrically connected to the conductive layer 115.

Referring to Figure 4D, after the flexible conductive structure 170 is formed, an electronic component 160 is disposed on the circuit layer 122. This electronic component 160 is electrically connected to the conductive layer 115 through the flexible conductive structure 170. Next, a metal layer 412' can be formed on the insulating substrate 116 by means of, for example, sputtering deposition.

Referring to Figure 4E, after the metal layer 412' is formed, multiple flexible connection structures 130 are formed in the magnetic material layer 114, the removable material 405 (shown in Figure 4D), the magnetic material layer 124, and the insulating substrate 116. These flexible connection structures 130 connect the circuit layer 122 and the metal layer 412' (shown in Figure 4D). In addition, some of the flexible connection structures 130 connect the electronic component 160 and the circuit layer 112.

Notably, the flexible connection structure 130 is formed by first removing a portion of the magnetic material layer 114, the removable material 405, and the second magnetic material layer 124 using a laser to form a plurality of first openings (not shown), which expose the wiring layer 122. Next, bonding material is filled into the first openings to form a bonding layer 138, which completely covers the inner walls of the first openings. After forming the bonding layer 138, a portion of the bonding layer 138 can be removed, for example, by laser drilling, to form a plurality of second openings (not shown) within the bonding layer 138, which expose the wiring layer 122. After the second opening is formed, a conductive material 135 can be filled into the second opening by means of electroplating, for example, and the conductive material 135 is electrically connected to the circuit layer 122.

After the flexible interconnect structure 130 is formed, the metal layer 412' can be patterned by means of, for example, photolithography and etching to form the circuit layer 112. The circuit layer 122 is electrically connected to the circuit layer 112 via the flexible interconnect structure 130. After the circuit layer 112 is formed, the removable material 405 is removed to form a gap layer 150 between the magnetic material layer 114 and the magnetic material layer 124. At this point, the circuit board 100 as shown in FIG. 1 has been substantially formed.

In summary, at least one embodiment of the present invention provides a repulsive force through opposite magnetic poles in a magnetic material layer, preventing two circuit substrates from directly contacting each other, but connecting (including electrical connections) the two circuit substrates through a flexible connection structure. In this way, without affecting the electrical connection between the two circuit substrates, displacement or deformation of one circuit substrate due to external force will not affect the other circuit substrate, thereby providing the feasibility of relative displacement of internal components (e.g., circuit substrates) within the circuit board.

Although the embodiments of the present invention have been disclosed above, they are not intended to limit the embodiments of the present invention. Anyone with ordinary skill in the art may make some modifications and refinements without departing from the spirit and scope of the embodiments of the present invention. Therefore, the scope of protection of the embodiments of the present invention shall be determined by the appended patent application.

100: Circuit board 102: Pad 104: Protective layer 110, 120: Circuit board substrate 112, 122: Circuit layer 114, 124: Magnetic material layer 114S, 124S: First magnetic pole 114N, 124N: Second magnetic pole 115: Conductive layer 116: Insulating substrate 118, 128, 138: Bonding layer 130: Flexible connection structure 135, 409: Conductive material 135s: Outer surface 150: Gap layer 160, 180: Electronic component 170: Flexible conductive structure 190: Covering layer 30: Electronic module 301: First module component 302: Second module component 405: Removable material 407: Insulating material 412’: Metal layer F1: External force RF1: Repulsive force TH1, TH2: Through-holes

The nature of the invention can be understood from the following detailed description and accompanying figures. It should be noted that many features are not drawn to industry-standard scale. In fact, the dimensions of various features can be arbitrarily increased or decreased for clarity of discussion. Figure 1 shows a cross-sectional view of a circuit board according to at least one embodiment of the invention. Figure 2 shows a cross-sectional view of a circuit board according to another embodiment of the invention. Figure 3A shows a schematic cross-sectional view of the circuit board according to at least one embodiment of the invention applied to an electronic module. Figure 3B shows a schematic cross-sectional view of the circuit board according to at least one embodiment of the invention applied to an electronic module. Figures 4A to 4E show cross-sectional views of a method for manufacturing the circuit board according to at least one embodiment of the invention.

100: Circuit Board

102: Pad

104: Protective Layer

110,120: Circuit substrate

112,122: Line layer

114, 124: Magnetic material layers

114S, 124S: First magnetic pole

114N, 124N: Second magnetic pole

115:Conductive layer

116: Insulating substrate

118, 128, 138: Bonding layer

130: Flexible connection structure

135: Conductive materials

135s: Outer surface

150: Interstitial layer

160: Electronic Components

170: Flexible conductive structure

190: Covering layer

RF1: Repulsive force

TH1, TH2: Through holes

Claims (10)

A circuit board comprising: two circuit substrates disposed opposite to each other, with a gap layer between the circuit substrates, wherein each of the circuit substrates comprises: a circuit layer; and a magnetic material layer disposed on the circuit layer, the magnetic material layer having a first magnetic pole and a second magnetic pole of opposite polarity, wherein the first magnetic pole is located between the circuit layer and the second magnetic pole, and the magnetic material layer of one circuit substrate faces the magnetic material layer of the other circuit substrate, and a repulsive force is formed between the second magnetic pole of one magnetic material layer and the second magnetic pole of the other magnetic material layer. The circuit board of claim 1 further comprises: a flexible connection structure disposed between the circuit substrates and connecting the circuit substrates, wherein one of the circuit substrates is electrically connected to the other circuit substrate via the flexible connection structure. The circuit board of claim 2, wherein the flexible connection structure further comprises: a conductive material connecting the circuit substrate, wherein a circuit layer of one of the circuit substrates is connected to a circuit layer of the other circuit substrate via the conductive material; and a bonding layer covering an outer surface of the conductive material. The circuit board of claim 1, wherein one of the circuit substrates further comprises: a conductive layer disposed between the magnetic material layer and the circuit layer; an insulating substrate disposed between the circuit layer and the conductive layer; and a bonding layer disposed between the insulating substrate and the magnetic material layer. The circuit board of claim 4 further comprises: a first electronic component disposed on one of the circuit substrates, wherein the other circuit substrate is located between the first electronic component and the other circuit substrate; and a flexible conductive structure disposed between the other circuit substrate and the first electronic component, wherein the flexible conductive structure extends from one of the circuit substrates through the gap layer and to the conductive layer of the other circuit substrate, and the first electronic component is electrically connected to at least one of the circuit substrates through the flexible conductive structure. The circuit board of claim 1, wherein each of the circuit substrates further comprises: a plurality of through-holes distributed within the circuit layer and the magnetic material layer, and connecting opposite sides of the circuit substrate. The circuit board of claim 1 further comprises: a cover layer disposed on one of the circuit substrates, wherein the one of the circuit substrates is located between the cover layer and the other circuit substrate. A method for manufacturing a circuit board includes: providing an insulating substrate; forming a conductive layer on the insulating substrate; forming a first magnetic material layer on the conductive layer, the first magnetic material layer having a first magnetic pole and a second magnetic pole of opposite polarity, wherein the first magnetic pole is located between the conductive layer and the second magnetic pole; forming a removable material on the first magnetic material layer, wherein the first magnetic material layer is located between the conductive layer and the removable material; forming a second magnetic material layer on the removable material, wherein the removable material is located between the second magnetic material layer and the first magnetic material layer; forming a first circuit layer on the second magnetic material layer, wherein the second magnetic material layer is located between the first circuit layer and the removable material; and After forming the first circuit layer, a plurality of flexible conductive structures are formed in the first magnetic material layer, the removable material, and the second magnetic material layer, wherein the flexible conductive structures are electrically connected to the conductive layers. The method of claim 8 further comprises: After forming the flexible conductive structure, forming a metal layer on the insulating substrate; After forming the flexible conductive structure, forming a plurality of flexible connection structures in the first magnetic material layer, the removable material, the second magnetic material layer, and the insulating substrate, wherein the flexible connection structures connect the first circuit layer and the metal layer; After forming the flexible connection structures, patterning the metal layer to form a second circuit layer, wherein the first circuit layer is electrically connected to the second circuit layer through the flexible connection structures; and After forming the second circuit layer, removing the removable material to form a gap layer between the first magnetic material layer and the second magnetic material layer. The method of claim 9, wherein forming the flexible connection structure comprises: removing a portion of the first magnetic material layer, the removable material, and the second magnetic material layer to form a plurality of first openings, wherein the first openings expose the first circuit layer; filling the first openings with an insulating material to form a bonding layer, wherein the bonding layer completely covers an inner wall of the first opening; after forming the bonding layer, removing a portion of the bonding layer to form a plurality of second openings, wherein the second openings expose the first circuit layer; and after forming the second openings, filling the second openings with a conductive material, wherein the conductive material is electrically connected to the first circuit layer.