TWI807433B - Circuit board and manufacturing method thereof, light-emitting apparatus and manufacturing method thereof - Google Patents

Abstract

A circuit board including a substrate, a circuit layer, a first solder resist layer and a second solder resist layer is provided. The circuit layer is disposed on the substrate. The circuit layer includes a first pad and a second pad. The first solder resist layer is disposed on the substrate and at least surrounds the first pad and the second pad. The second solder resist layer covers the first solder resist layer. A method of manufacturing a circuit board, a light-emitting apparatus and a manufacturing method thereof are also provided.

Description

Circuit board and manufacturing method thereof, light emitting device and manufacturing method thereof

The present invention relates to an electronic product and its manufacturing method, and in particular to a circuit board and its manufacturing method, a light emitting device and its manufacturing method.

In the manufacturing process of circuit boards, the step of "solder mask window opening" is usually to remove the solder mask material corresponding to the place to be soldered (usually the connection pad; but not limited) to expose the corresponding soldered place. The part that has not been opened can still be covered with the substrate, other insulating materials or conductive materials that do not want to be exposed. For example, the solder resist layer can still cover part of the lines (commonly known as: cover lines). The circuit covered by the solder resist layer can avoid contact with other conductive materials in the subsequent manufacturing process by the solder resist layer covering it.

Due to the development of technology and/or the requirements of products, the layout density of circuit boards may need to be higher and higher. In other words, the cover line may become closer and closer to the window opening. Therefore, how to improve the quality of the covering line of the circuit board so that the solder mask can better cover or wrap the desired covering line, so as to improve the yield rate and product reliability, has become an urgent problem to be solved.

The invention provides a circuit board and its manufacturing method, a light emitting device and its manufacturing method, which can have better yield or quality.

The circuit board of the present invention includes a base material, a circuit layer, a first solder resist layer and a second solder resist layer. The circuit layer is located on the substrate. The circuit layer includes a first pad and a second pad. The first solder resist layer is located on the base material and at least surrounds the first pad and the second pad. The second solder resist layer covers the first solder resist layer.

In an embodiment of the invention, the first solder resist layer is in contact with the second solder resist layer.

In an embodiment of the present invention, there is an interface between the first solder resist layer and the second solder resist layer.

In an embodiment of the invention, the circuit layer includes a first conductive layer and a second conductive layer. The second conductive layer covers the first conductive layer.

In an embodiment of the present invention, the light reflectance of the second solder resist layer is greater than or equal to 80%.

In an embodiment of the present invention, the substrate has a bonding area and a pin area, the circuit layer further includes a plurality of pins, the first pad and the second pad are located in the bonding area, the pins are located in the pin area, and the second solder resist layer is away from the pin area.

In an embodiment of the present invention, the second solder resist layer is located in the bonding area, and the second solder resist layer exposes part of the first solder resist layer.

The manufacturing method of the circuit board of the present invention includes the following steps: providing a substrate structure, which includes a substrate and a first conductive layer on the substrate; forming a first solder resist layer on the substrate structure, and the first solder resist layer surrounds at least part of the first conductive layer; forming a second solder resist layer on the substrate structure, and the second solder resist layer covers the first solder resist layer; pad.

The light-emitting device of the present invention includes the aforementioned circuit board and light-emitting elements. The light emitting element is disposed on the circuit layer of the circuit board and electrically connected to the first pad and the second pad.

The manufacturing method of the light-emitting device of the present invention includes the following steps: providing the aforementioned circuit board; disposing the light-emitting element on the circuit layer of the circuit board to be electrically connected to the first pad and the second pad.

Based on the above, by using the second solder resist layer covering the first solder resist layer, the circuit board and/or the light emitting device can have better yield or quality.

The present invention will be described more fully with reference to the drawings of this embodiment. However, the present invention can also be embodied in various forms and should not be limited to the embodiments described herein. The thicknesses of layers and regions in the drawings may be exaggerated for clarity. The same or similar reference numbers indicate the same or similar elements, and the following paragraphs will not repeat them one by one. In addition, for the sake of clarity, some film layers or components may be omitted in the drawings.

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed descriptions of the embodiments with reference to the drawings. The directional terms mentioned in the following embodiments, such as "upper" or "lower", are only referring to the directions of the attached drawings. Accordingly, the directional terms used are illustrative, not limiting, of the invention.

1A to 1D are partial cross-sectional schematic views of a partial manufacturing method of a circuit board according to an embodiment of the present invention. FIG. 2 is a partial top view of a circuit board according to an embodiment of the present invention. FIG. 1D may be a partial cross-sectional schematic diagram corresponding to a section in FIG. 2 .

FIG. 3 is a schematic partial cross-sectional view of a circuit board according to a possible embodiment of the present invention, wherein FIG. 3 may be the same or similar enlarged view of the region R1 in FIG. 1D .

Referring to FIG. 1A , a substrate structure 110 is provided. The substrate structure 110 may include a substrate 120 and a patterned first conductive layer 141 . The first conductive layer 141 may be located on the substrate 120 .

In one embodiment, the base material 120 may include a rigid substrate, but the invention is not limited thereto. The rigid substrate may include glass, a glass fiber layer containing epoxy resin (such as: a common FR4 substrate), a bismaleimide triazine (bismaleimide triazine; BT) board, a board similar to the above (such as: a BT-like board (BT-like board), FR5 board, etc.), or other suitable boards.

In one embodiment, the base material 120 may include a flexible substrate, but the invention is not limited thereto. The material of the flexible substrate includes, for example, polyimide (PI) and polyethylene terephthalate (PET), but the invention is not limited thereto. For example, the flexible substrate may include a PI board, an MPI (Modify PI) board, an LCP (liquid crystal substrate) board or other suitable boards.

In one embodiment, the substrate 120 may include a rigid-flex board.

In one embodiment, the color of the substrate 120 may be white, but the invention is not limited thereto. For example, the base material 120 may include a white LCP board, a white BT board or a white BT-like board, but the invention is not limited thereto.

It should be noted that, in FIG. 1A or other similar figures, the substrate 120 is only schematically depicted. That is to say, the substrate 120 may be a bulk material with a single structure, a bulk material coated with at least one film layer, a stack of multiple materials or film layers, or other suitable analogs.

In this embodiment, based on the consideration of conductivity, the material of the first conductive layer 141 may include metal. For example, the material of the first conductive layer 141 may include copper. The first conductive layer 141 can be formed by a build-up method or a subtraction method, which is not limited in the present invention.

In one embodiment, the first conductive layer 141 may be formed by plating and photolithography, but the invention is not limited thereto.

In one embodiment, the base structure 110 may be formed of a copper foil substrate. For example, the copper foil on the copper foil substrate can be patterned in a suitable manner.

Referring to FIG. 1A to FIG. 1B , a first solder resist layer (a type of insulating layer) 151 is formed on the substrate structure 110 . The first solder resist layer 151 at least surrounds a portion of the first conductive layer 141 . For example, the first solder resist layer 151 may have an opening, and the opening exposes part of the first conductive layer 141 .

In this embodiment, there may be a distance 141d between the first solder resist layer 151 and part of the sidewall 141a of the first conductive layer 141 , but the invention is not limited thereto.

In an embodiment, a solder resist material (eg, liquid photoimageable solder mask (LPSM); but not limited to) can be coated on the base structure 110 . Then, part of the solder resist material may be removed by etching or other suitable patterning methods, so as to expose at least part of the first conductive layer 141 . The solder resist material on the base structure 110 can be appropriately cured (eg, photocured and/or thermally cured) to form a corresponding first solder resist layer 151 .

Referring to FIG. 1B to FIG. 1C , a second solder resist layer (a type of insulating layer) 152 is formed on the substrate structure 110 . The second solder resist layer 152 may cover the first solder resist layer 151 .

In one embodiment, the first solder resist layer 151 may be formed of thermal curable ink or thermal curable ink, and the second solder resist layer 152 may be formed of developing ink.

In an embodiment, a reflective layer (such as the reflective layer 260 described later, but not limited thereto) can be further formed on the second solder resist layer 152 .

In one embodiment, the first solder resist layer 151 may be formed by developing ink, and the second solder resist layer 152 may be formed by a material, film or sheet with high reflectivity (eg: reflectivity at about 470nm>70%; reflectivity at about 550nm>70%; and/or reflectivity in the range of about 470nm~550nm>70%). For example, a patterned film or sheet having the aforementioned properties can be attached to the substrate structure 110 to form the corresponding second solder resist layer 152 .

In one embodiment, the color of the first solder resist layer 151 may be white, and the color of the second solder resist layer 152 may be silver or metallic luster having or similar high reflective properties.

In a possible embodiment, the material and/or forming method of the second solder resist layer 152 may be the same or similar to the material and/or forming method of the first solder resist layer 151 , but the present invention is not limited thereto.

In this embodiment, the second solder resist layer 152 may cover the surface of the first solder resist layer 151 away from the first conductive layer 141 . For example, on a cross section (such as the cross section shown in FIG. 1C ; but not limited thereto), the first solder resist layer 151 may have opposite first side 151 a and second side 151 b, wherein the second side 151 b is farther from the first side 151 a than the first side 151 a closest to the first conductive layer 141 (ie, the aforementioned first solder resist layer 151 for illustration), and the second solder resist layer 152 may cover the second side 151 b of the first solder resist layer 151 .

In one embodiment, during the patterning process of the first solder resist layer 151 , there may be slight or unexpected undercut phenomenon; and/or, when the corresponding first solder resist layer 151 is formed through the curing step, there may be a gap between part of the first solder resist layer 151 (eg, the edge portion of the first solder resist layer 151 ) and the substrate 120 due to the difference in coefficient of thermal expansion (Coefficient of Thermal Expansion; CTE) between materials. Slight or unexpected peeling. Therefore, during the process of forming the second solder resist layer 152 , the second solder resist layer 152 can be correspondingly filled into the aforesaid undercut and/or peeled off. For example, when the solder resist material for forming the second solder resist layer 152 is coated on the substrate structure 110 , part of the solder resist material may be filled into the aforementioned undercut and/or peeled off. In this way, the production yield and/or quality of the formed circuit board 100 (indicated in FIG. 1D or FIG. 2 ) can be improved.

In this embodiment, the first solder resist layer 151 and the second solder resist layer 152 may be in contact. Moreover, since the first solder resist layer 151 and the second solder resist layer 152 are made of different materials and/or are formed through different steps. In this way, there may be a corresponding interface (interface) 159 between the contacting first solder resist layer 151 and the second solder resist layer 152 . In one embodiment, the first solder resist layer 151 and the second solder resist layer 152 can be regarded as different solder resist layers.

Referring to FIG. 1C to FIG. 1D , a second conductive layer 142 is formed on the first conductive layer 141 . For example, the second conductive layer 142 may be formed on the part of the first conductive layer 141 exposed by the first solder resist layer 151 and the second solder resist layer 152 by plating or other suitable methods. At least a portion of the first conductive layer 141 and at least a portion of the second conductive layer 142 may constitute the circuit layer 130 . That is to say, the circuit layer 130 may include a corresponding first conductive layer 141 and a corresponding second conductive layer 142 .

In an embodiment, the oxidation resistance of the second conductive layer 142 may be better than that of the first conductive layer 141 . In an embodiment, the second conductive layer 142 may include a nickel-gold layer or a nickel-palladium-gold layer. For example, the second conductive layer 142 may include an electroless nickel immersion gold (ENIG) layer or an electroless nickel electroless palladium immersion gold (ENEPIG) layer.

As shown in FIG. 3 , in one embodiment, even if (but there may not be) in the process of forming the first solder resist layer 151, there may be slight or unexpected undercuts and/or peeling off, but because the second solder resist layer 152 covering the first solder resist layer 151 can fill in the aforementioned undercuts and/or peeling off. Therefore, the possibility that the second conductive layer 142 formed later will fill the aforementioned undercut and/or peeled off can be reduced. In this way, the possibility of unexpected electrical changes (such as possible short circuit or electrical signal instability; but not limited) caused by the second conductive layer 142 filling the aforementioned undercut and/or peeling can be reduced. For example, during the formation of the second conductive layer 142 , the possibility that the corresponding conductive material contacts the conductive elements embedded in the first solder resist layer 151 from the aforesaid undercut and/or peeled off can be reduced. In this way, the production yield and/or quality of the formed circuit board 100 can be improved. In addition, as shown in FIG. 3 , in the above case, part of the second solder resist layer 152 may be located between the first solder resist layer 151 and the base material 120 .

After the above process, the circuit board 100 of this embodiment can be substantially completed.

Referring to FIG. 1D and FIG. 2 , the circuit board 100 includes a base material 120 , a circuit layer 130 , a first solder resist layer 151 and a second solder resist layer 152 . The circuit layer 130 is located on the substrate 120 . The circuit layer 130 includes a first pad 131 and a second pad 132 . The first solder resist layer 151 is located on the substrate 120 . The first solder resist layer 151 at least surrounds the first pad 131 and the second pad 132 . The second solder resist layer 152 covers the first solder resist layer 151 .

In this embodiment, the first pad 131 and the second pad 132 may be electrically separated from each other.

In this embodiment, the layout design of the circuit layer 130 can be adjusted according to requirements, which is not limited in the present invention. That is to say, in the circuit layer 130 , the parts that are not connected in the drawing may be electrically connected by other not-shown places and/or other conductive elements.

In this embodiment, the substrate 120 may have a bonding area 121 and a lead area 124 . The first pad 131 and the second pad 132 can be located in the bonding area 121 .

In this embodiment, the circuit layer 130 may further include a plurality of pins 134 and connection lines 133 . The pins 134 may be located in the pin area 124 , and the connection wires 133 may extend from the bonding area 121 to the pin area 124 . In one embodiment, the pin 134 can be electrically connected to the corresponding pad (eg, the first pad 131 or the second pad 132 ) through the corresponding connection wire 133 .

In an embodiment, the area corresponding to the connection line 133 in the circuit board 100 may be suitable for bending. For example, since the connection line 133 is only covered by a solder resist layer (eg, the first solder resist layer 151 ), the area corresponding to the connection line 133 can be made more suitable for bending (eg, compared to the bonding area 121 ). For another example, the first solder resist layer 151 can be formed by ink suitable for flexible boards (such as: polyimide ink (PI ink) or photoimageable coverlay). Therefore, compared with the solder resist layer formed by ink commonly used for rigid boards, the circuit board 100 can have wider applicability, better yield or quality. In terms of application methods, polyimide ink (PI ink) or photoimageable coverlay (Photoimageable Coverlay) able Coverlay) may have lower rebound force, but the present invention does not limit the use of other materials. For example, traditional coverlay (CVL) (such as: PI coverlay) or liquid photo imageable (liquid photo imageable; LPI) ink can also be used.

In one embodiment, the circuit board 100 can be electrically connected to other electronic components (eg, Chip On Film (COF), but not limited to) via its pins 134 .

In the embodiment shown in FIG. 1D , the circuit board 100 is a single-sided circuit (for example, there is a circuit layer 130 on one surface of the substrate 120 ), but the present invention is not limited thereto. In other embodiments or other similar embodiments not shown, the circuit board 100 may be a double-sided circuit. For example, the substrate 120 may be located between the circuit layer 130 and other circuit layers. Moreover, part of the wiring in the aforementioned other circuit layers may be configured corresponding to the first pad 131 , the second pad 132 , the connection line 133 or the pin 134 , but the present invention is not limited thereto.

In this embodiment, the second solder resist layer 152 may be far away from the lead area 124 , but the invention is not limited thereto.

In this embodiment, the second solder resist layer 152 is located at the bonding area 121 , and the second solder resist layer 152 exposes part of the first solder resist layer 151 .

FIG. 4 is a schematic partial cross-sectional view of a circuit board according to a possible embodiment of the present invention. The circuit board 200 of this embodiment is similar to the circuit board 100 of the foregoing embodiments, and its similar components are denoted by the same reference numerals, and have similar functions, structures, materials and/or formation methods, and descriptions thereof are omitted.

Referring to FIG. 1D / FIG. 2 and FIG. 4 , the circuit board 200 includes a substrate 120 , a first circuit layer 130 , a first solder resist layer 151 , a second solder resist layer 152 , a third solder resist layer 253 , a second circuit layer 230 and conductive vias 235 . The base material 120 may be located between the first wiring layer 130 and the second wiring layer 230 . The conductive vias 235 may penetrate through the substrate 120 . Corresponding circuits in the first circuit layer 130 and corresponding circuits in the second circuit layer 230 can be electrically connected through conductive vias 235 .

In this embodiment, the wiring design of the second circuit layer 230 can be adjusted according to requirements, which is not limited in the present invention. That is to say, in the second circuit layer 230 , the unconnected parts in the drawing may be electrically connected through other unshown places and/or other conductive elements.

In this embodiment, the circuit board 200 may further include a reflective layer 260 . The reflective layer 260 can cover the second solder resist layer 152 . The reflectivity of the reflective layer 260 is substantially greater than or equal to 85%. Preferably, the reflectivity of the reflective layer 260 may be greater than or equal to 90%.

In one embodiment, the color of the reflective layer 260 may be silver or metallic luster having or similar high reflective properties.

In one embodiment, the reflective layer 260 can be formed on the second solder resist layer 152 by sputtering, vapor deposition, chemical plating, electroplating, chemical replacement reaction, silver mirror reaction or other suitable methods. For example, the reflective layer 260 may include aluminum, silver, gold, copper, beryllium, chromium, molybdenum, platinum, nickel, iron or any combination thereof, or other metal layers with high reflectivity. In one embodiment, the reflectivity of silver at a wavelength of 800nm can be as high as about 99.2%, and the reflectivity of silver at a wavelength of 500nm can also reach about 97.9%. Therefore, silver can be the best material for the aforementioned reflective layer at the wavelength of visible light and near-infrared light. In addition, aluminum also has good reflectivity at near-ultraviolet light, visible light, near-infrared light and other wavelengths (the reflectivity of aluminum at a wavelength of 800nm is about 86.7%, and at a wavelength of 500nm it can reach as high as about 91.8%). However, due to its soft and easy to oxidize characteristics, when it is used as the material of the aforementioned reflective layer, it must be coated with a protective layer on the surface, and it can also be additionally coated with metal or non-metallic coatings to improve its reflectivity at specific wavelengths. The reflectivity of gold and copper between 650nm and 800nm is also very good (the reflectivity of gold at the wavelength of 800nm and 650nm is about 98.0% and 95.5 respectively, and the reflectivity of copper at the wavelength of 800nm and 650nm is about 98.1% and 96.6 respectively), but the reflectivity at the wavelength of 500nm is poor, so gold and copper can also be used as the reflective layer at the wavelength of 800nm and 650nm. material. Certainly, the aforementioned materials or methods are only used for illustration, and are not intended to limit the material of the reflective layer 260 .

In this embodiment, the circuit board 200 may further include a third solder resist layer (a type of insulating layer) 253 . The third solder resist layer 253 may cover the second wiring layer 230 .

In one embodiment, the material or formation method of the third solder resist layer 253 may be the same or similar to that of the first solder resist layer 151 , but the invention is not limited thereto.

In this embodiment, the circuit board 200 may further include a reinforcing material 270 . The reinforcing material 270 may be configured corresponding to the lead area 124 of the substrate 120 . In one embodiment, the Young's modulus of the reinforcing material 270 may be greater than the Young's modulus of the base material 120 . In this way, when the pins 134 of the circuit board 200 (or the pin area 124 of the substrate 120 ) are connected to other components, the damage or damage of the circuit board 200 can be reduced.

Fig. 5 is a schematic partial cross-sectional view of a light emitting device according to an embodiment of the present invention.

Some examples of manufacturing methods of the light emitting device 500 are as follows.

Please refer to Figure 5 to provide a circuit board. In this embodiment, the provided circuit board may be the same circuit board as the aforementioned circuit board 100 , therefore, in the subsequent description and/or corresponding drawings, the circuit board 100 and its corresponding symbols are used for illustration. In an embodiment, the provided circuit board may be a circuit board similar to the aforementioned circuit board 100 (eg, the circuit board 200 , but not limited thereto).

Please continue to refer to FIG. 5 , disposing the light emitting element 580 on the circuit layer 130 of the circuit board 100 to be electrically connected to the first pad 131 and the second pad 132 of the circuit layer 130 . For example, the light emitting element 580 can be electrically connected to the corresponding first pad 131 and the second pad 132 through the corresponding conductive connector 585 . The conductive connector 585 may include solder balls, but the present invention is not limited thereto.

In an embodiment, the light reflectance of the second solder resist layer 152 may be greater than or equal to 80%. In this way, the performance of the light emitting device 500 can be improved. In one embodiment, the appearance of the second solder resist layer 152 may be white, silvery white or a similar color with metallic luster.

In one embodiment, the light emitting element 580 may include a light emitting diode. The aforementioned light emitting diodes may include red light emitting diodes, green light emitting diodes, blue light emitting diodes or white light emitting diodes, but the present invention is not limited thereto.

In one embodiment, the light emitting device 500 may be a backlight module, but the invention is not limited thereto.

In one embodiment, the light emitting device 500 may be a display panel or a part of the display panel, but the invention is not limited thereto.

To sum up, the circuit board and/or light-emitting device of the present invention can have better yield or quality through the second solder resist layer covering the first solder resist layer.

100: circuit board 110: Substrate structure 120: Substrate 121: Junction zone 124: Pin area 130: line layer 131: The first pad 132: Second pad 133: Connecting line 134: pin 230: line layer 235: Conductive vias 141: the first conductive layer 141a: side wall 141d: Spacing 142: second conductive layer 151: The first solder resist layer 151a, 151b: side 152: Second solder resist layer 253: The third solder resist layer 159: interface 260: reflective layer 270: reinforcement material 500: Lighting device 580: light emitting element 585: Conductive connector R1: Region

1A to 1D are partial cross-sectional schematic views of a partial manufacturing method of a circuit board according to an embodiment of the present invention. FIG. 2 is a partial top view of a circuit board according to an embodiment of the present invention. FIG. 3 is a schematic partial cross-sectional view of a circuit board according to a possible embodiment of the present invention. FIG. 4 is a schematic partial cross-sectional view of a circuit board according to a possible embodiment of the present invention. Fig. 5 is a schematic partial cross-sectional view of a light emitting device according to an embodiment of the present invention.

100: circuit board

120: Substrate

121: Junction zone

124: Pin area

130: line layer

131: The first pad

132: Second pad

133: Connecting line

134: pin

141: the first conductive layer

142: second conductive layer

151: The first solder resist layer

152: Second solder resist layer

R1: Region

Claims (10)

A circuit board, comprising: Substrate; a circuit layer located on the substrate, and the circuit layer includes a first pad and a second pad; a first solder resist layer located on the base material and surrounding at least the first pad and the second pad; and The second solder resist layer covers the first solder resist layer. The circuit board according to claim 1, wherein the first solder resist layer is in contact with the second solder resist layer. The circuit board according to claim 2, wherein there is an interface between the first solder resist layer and the second solder resist layer. The wiring board as claimed in item 1, wherein the wiring layer includes: the first conductive layer; and The second conductive layer covers the first conductive layer. The circuit board according to claim 1, wherein the light reflectance of the second solder resist layer is greater than or equal to 80%. The circuit board as described in claim item 1, wherein: The substrate has a bonding area and a pin area; The wiring layer further includes a plurality of pins, wherein the first pad and the second pad are located in the bonding area, and the plurality of pins are located in the pin area; and The second solder resist layer is far away from the lead area. The circuit board according to claim 6, wherein the second solder resist layer is located in the bonding area, and the second solder resist layer exposes part of the first solder resist layer. A method of manufacturing a circuit board, comprising: providing a substrate structure, which includes a substrate and a first conductive layer positioned on the substrate; forming a first solder resist layer on the substrate structure, and the first solder resist layer surrounds at least part of the first conductive layer; forming a second solder resist layer on the substrate structure, and the second solder resist layer covers the first solder resist layer; and forming a second conductive layer on the first conductive layer to form a circuit layer including the first conductive layer and the second conductive layer, wherein: The circuit layer includes a first pad and a second pad; and The first solder resist layer at least surrounds the first pad and the second pad. A lighting device comprising: Such as the circuit board of claim 1; and The light emitting element is disposed on the circuit layer of the circuit board and electrically connected to the first pad and the second pad. A method of manufacturing a light emitting device, comprising: Provide the circuit board as in claim 1; The light emitting element is disposed on the circuit layer of the circuit board to be electrically connected to the first pad and the second pad.

Images