Printed circuit board

Abstract

To provide a printed circuit board including a glass layer, capable of compensating for problems with the cracking characteristics of the glass layer and improving reliability.SOLUTION: The present disclosure relates to a printed circuit board including a glass layer, a first insulating layer disposed on the glass layer, a first wiring layer disposed on the first insulating layer, and a first protective layer covering a portion of the top surface of the glass layer, at least a portion of the side surface of the glass layer, and at least a portion of the side surface of the first insulating layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to printed circuit boards. [Background technology]

[0002] Recently, with the development of artificial intelligence (AI) technology, multi-chip packages containing memory chips such as high-bandwidth memory (HBM) and processor chips such as central processing units (CPUs), graphics processing units (GPUs), application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs) are being used to process data that has increased exponentially. In particular, the number of CPU and GPU cores in server products is rapidly increasing, driving demand for large-area substrates. Glass materials offer thermal and mechanical stability, helping to overcome warpage issues, leading to ongoing efforts to use them. Summary of the Invention [Problem to be solved by the invention]

[0003] Among the various objects of the present disclosure is to provide a printed circuit board that includes a glass layer.

[0004] Another of the various objects of the present disclosure is to provide a printed circuit board that can compensate for the problem of cracking characteristics of the glass layer.

[0005] Another of the various objects of the present disclosure is to provide a printed circuit board that can improve reliability. [Means for solving the problem]

[0006] One of the various solutions proposed through the present disclosure is to provide a printed circuit board including a glass layer, a first insulating layer disposed on the glass layer, a first wiring layer disposed on the first insulating layer, and a first protective layer covering a portion of the top surface of the glass layer, at least a portion of the side surface of the glass layer, and at least a portion of the side surface of the first insulating layer.

[0007] Another of the various solutions proposed through the present disclosure is to provide a printed circuit board including a glass layer, a first insulating layer disposed on the glass layer, and a first wiring layer disposed on the first insulating layer, wherein the width of the first insulating layer is smaller than the width of the glass layer. [Effects of the Invention]

[0008] Among other advantages of the present disclosure is the provision of a printed circuit board including a glass layer.

[0009] Another advantage of the present disclosure is that it provides a printed circuit board that can overcome the problem of cracking characteristics of the glass layer.

[0010] Another advantage of the present disclosure, among other advantages, is that it is possible to provide a printed circuit board that can improve reliability. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of a printed circuit board. [Figure 2] FIG. 10 is a cross-sectional view schematically showing another example of a printed circuit board. [Figure 3] FIG. 10 is a cross-sectional view schematically illustrating yet another example of a printed circuit board. [Figure 4] FIG. 10 is a cross-sectional view schematically illustrating yet another example of a printed circuit board. [Figure 5] 1A to 1C are cross-sectional views schematically showing an example of a method for manufacturing a printed circuit board. [Figure 6]1A to 1C are cross-sectional views schematically showing an example of a method for manufacturing a printed circuit board. [Figure 7] 1A to 1C are cross-sectional views schematically showing an example of a method for manufacturing a printed circuit board. [Figure 8] 1A to 1C are cross-sectional views schematically showing an example of a method for manufacturing a printed circuit board. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described below with reference to the accompanying drawings. The shapes and sizes of elements in the drawings may be scaled (or highlighted or simplified) for clarity.

[0013] <Printed circuit board> FIG. 1 is a cross-sectional view that schematically illustrates an example of a printed circuit board.

[0014] 1 , the printed circuit board according to an example may include a glass layer 110, a first insulating layer 111 disposed on the glass layer 110, a first wiring layer 121 disposed on the first insulating layer 111, and a first protective layer 150 covering a portion of the top surface of the glass layer 110, at least a portion of the side surfaces of the glass layer 110, and at least a portion of the side surfaces of the first insulating layer 111. Furthermore, in the printed circuit board according to an example, the thermal expansion coefficient of the first protective layer 150 may be greater than the thermal expansion coefficient of the first insulating layer 111.

[0015] The printed circuit board according to an embodiment includes the glass layer 110, which can have excellent flatness and advantageously control warpage due to a low coefficient of thermal expansion (CTE). In particular, the printed circuit board according to an embodiment can have the glass layer 110 as a core, which is advantageous not only for controlling warpage of the completed printed circuit board but also for controlling warpage during lamination of other insulating layers. Furthermore, the flatness can be increased, which is advantageous for forming high-density fine circuits with fine pitches. Furthermore, the dielectric properties of the glass layer 110, such as the variable Dk characteristics of glass (Dk 2.5 to 11), can reduce the number of layers in the printed circuit board, thereby increasing design flexibility.

[0016] The glass layer 110 may include glass, which is an amorphous solid. Examples of glass include pure silicon dioxide (approximately 100% SiO), soda-lime glass, borosilicate glass, and aluminosilicate glass. However, alternative glass materials, such as fluoroglass, phosphate glass, and chalcogenide glass, may also be used for the glass layer 110. Furthermore, other additives may be included to form glass with specific physical properties. These additives may include calcium carbonate (e.g., lime) and sodium carbonate (e.g., soda), as well as magnesium, calcium, manganese, aluminum, lead, boron, iron, chromium, potassium, sulfur, and antimony, as well as carbonates and / or oxides of these and other elements. The glass layer 110 is a layer that is distinct from materials containing glass fiber (glass fiber, glass cloth, glass fabric), such as CCL (Copper Clad Laminate) and PPG (Prepreg), and can be understood as, for example, sheet glass.

[0017] The first insulating layer 111 may be composed of one or more insulating layers and may include an organic insulating material. The organic insulating material may include a thermosetting resin such as an epoxy resin, a thermoplastic resin such as a polyimide, or a material containing a resin together with an inorganic filler, an organic filler, and / or glass fiber (glass fiber, glass cloth, glass fabric). For example, the insulating material may be a non-photosensitive insulating material such as Ajinomoto Build-up Film (ABF) or Prepreg (PPG), but is not limited thereto. Other polymer materials may also be used. The insulating material may also be a photosensitive insulating material such as a photoimageable dielectric (PID). The insulating material may also include an adhesive sheet such as a bonding sheet (BS). The first insulating layer 111 may be disposed on the upper and lower surfaces of the glass layer 110.

[0018] The width of the first insulating layer 111 may be narrower than the width of the glass layer 110. The printed circuit board according to an example may be a result of forming the first insulating layer 111 on the glass layer 110, removing a portion of the first insulating layer 111, and then cutting the glass layer 110.

[0019] To increase production yields, printed circuit boards may be manufactured in panel or strip form and then singulated into individual unit boards. When cutting the strip boards for singulation, the first insulating layer 111, which has a relatively higher thermal expansion coefficient, may expand or contract more than the glass layer 110, which has a relatively lower thermal expansion coefficient. If cooling is performed during the singulation step, the first insulating layer 111 may contract more, creating a stress difference between it and the glass layer 110, which may cause tensile stress on the side of the glass layer 110, which may lead to cracks on the side of the glass layer 110. While a printed circuit board with cracks may be defective, microcracks occurring inside or outside the glass layer 110 may cause defects when the printed circuit board is subsequently used.

[0020] In the printed circuit board according to an example, singulation is performed in the step of cutting the glass layer 110 after the step of removing a portion of the first insulating layer 111, so that stress generated when the first insulating layer 111 and the glass layer 110 are simultaneously cut can be minimized, and at this time, a portion of the first insulating layer 111 can be removed by forming a groove by removing more than the cutting position for singulation. Therefore, since a portion of the first insulating layer 111 is removed more than the cutting position of the glass layer 110, the width of the first insulating layer 111 according to an example may be narrower than the width of the glass layer 110.

[0021] Meanwhile, the width of the first insulating layer 111 can be measured by photographing a cross section of the printed circuit board cut in the lamination direction using a scanning microscope, etc. The width of the first insulating layer 111 can mean the horizontal distance across both sides of the first insulating layer 111, and can be the average value of distances measured at any five points. Meanwhile, the width of the glass layer 110 can be measured in the same manner, and can be measured as the horizontal distance across both sides of the glass layer 110.

[0022] The first wiring layer 121 may be composed of one or more wiring layers and may include a metal. Metals may include copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and / or alloys thereof. Preferably, but not limited to, copper (Cu). The first wiring layer 121 may perform various functions depending on the design. For example, it may include a signal pattern, a power pattern, a ground pattern, etc. These patterns may each have various forms, such as a line, a plane, or a pad. The first wiring layer 121 may include an electroless plating layer (or chemical copper) and an electrolytic plating layer (or electrolytic copper). Alternatively, it may include a metal foil (or copper foil) and an electrolytic plating layer (or electrolytic copper). Alternatively, it may include a metal foil (or copper foil), an electroless plating layer (or chemical copper), and an electrolytic plating layer (or electrolytic copper). A sputtering layer may be included instead of the electroless plating layer (or chemical copper), or both may be included if necessary. The first wiring layer 121 may be disposed on the first insulating layer 111, but is not limited thereto, and may also be disposed on the upper surface and / or the lower surface of the glass layer 110.

[0023] The first wiring layer 121 may be formed by any one of SAP (Semi Additive Process), MSAP (Modified Semi Additive Process), TT (Tenting), or subtractive process, but is not limited thereto and may be formed by any process that can form a circuit on a printed circuit board. The first wiring layer 121 may also be formed by different processes depending on the application, design, etc.

[0024] Meanwhile, the printed circuit board according to an example may further include a first via layer 131 penetrating at least a portion of the first insulating layer 111 to connect the first wiring layers 121 to each other.

[0025] The first via layer 131 may include a metal. Examples of the metal include copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and / or alloys thereof. Preferably, the first via layer 131 may include, but is not limited to, copper (Cu). The first via layer 131 may include filled vias that fill the respective via holes, or may include conformal vias arranged along the wall surfaces of the via holes. The first via layer 131 may perform various functions depending on the design. For example, it may include a ground via, a power via, a signal via, etc. Like the first wiring layer 121, the first via layer 131 may include an electroless plating layer (or chemical copper) and an electrolytic plating layer (or electrolytic copper). Alternatively, it may include a metal foil (or copper foil) and an electrolytic plating layer (or electrolytic copper). Instead of the electroless plating layer (or chemical copper), a sputtering layer may be included, or both may be included if necessary.

[0026] Meanwhile, the printed circuit board according to an example may further include a through via 130 that penetrates the glass layer 110 .

[0027] The through via 130 may include a metal. Examples of the metal include copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and / or alloys thereof. Preferably, the metal may include, but is not limited to, copper (Cu). The through via 130 may penetrate the upper and lower surfaces of the glass layer 110. The upper and lower surfaces of the through via 130 may be substantially coplanar with the upper and lower surfaces of the glass layer 110, respectively. The through via 130 may be a so-called filled via, which is filled with a metal layer, but is not limited thereto. The through via 130 may have various structures, such as a conformal via arranged along the wall surface of a via hole. The through via 130 may perform various functions depending on the design. For example, the through via 130 may be a ground via, a power via, a signal via, etc. The through via 130 may have a substantially circular, elliptical, or polygonal shape in a plane, but is not limited thereto, and may have a composite shape in which various shapes are combined in a plane, for example, to ensure adhesion by increasing the specific surface area. The side surface of the through via 130 may be substantially perpendicular to the upper and lower surfaces of the through via 130, but is not limited thereto, and may be tapered to have an hourglass shape or the like in cross section as necessary.

[0028] According to an example, the printed circuit board may further include a solder resist layer 140 disposed on the first insulating layer 111. The solder resist layer 140 may be disposed on the top and bottom sides of the printed circuit board to protect the printed circuit board from the outside. The solder resist layer 140 may be a known solder resist, and may include, but is not limited to, a liquid or film-type material. Other types of insulating materials may be used, such as a thermosetting resin and an inorganic filler dispersed in the thermosetting resin, but may not include glass fiber. The insulating resin may be a photosensitive insulating resin, and the filler may be, but is not limited to, an inorganic filler and / or an organic filler. Other polymer materials may also be used as needed. The solder resist layer 140 may have openings, through which at least a portion of the first wiring layer 121 may be exposed. The first wiring layer 121 exposed through the openings may be connected to a device such as a semiconductor chip, or may be connected to a main board or another printed circuit board. The wiring layer exposed through the opening functions as a pad, and a surface treatment layer may be further formed on the pad as needed, or a metal bump or post may be further formed on the pad, or the pad may have a protruding structure in the form of a pillar as needed.

[0029] The printed circuit board according to an example may include a first protective layer 150 covering a portion of the top surface of the glass layer 110, at least a portion of the side surface of the glass layer 110, and at least a portion of the side surface of the first insulating layer 111. That is, the first protective layer 150 may be disposed on the outer surface of the printed circuit board. This may be the result of forming the first protective layer 150 on the side surface of each unit board after singulating the boards in panel units or strip units during the manufacturing process of the printed circuit board according to an example. The first protective layer 150 may be formed on the side surface of the printed circuit board by a method such as liquid coating or spraying, or may be formed by dipping one side surface of the printed circuit board into a liquid material. The first protective layer 150 may be integrally formed and extend over at least a portion of the side surface of the glass layer 110, the top surface of the glass layer 110, and the side surface of the first insulating layer 111. In this case, the first protective layer 150 is not limited to covering at least a portion of the upper surface of the glass layer 110, but may also cover at least a portion of the lower surface of the glass layer 110. The first protective layer 150 may also cover at least a portion of the side surface of the solder resist layer 140. This may be the result of singulating the substrate in strip units after forming the solder resist layer 140. However, this is not necessarily limited thereto, and in the case where the solder resist layer 140 is formed after forming the first protective layer following the singulation step, the solder resist layer 140 may also be formed on the first protective layer 150.

[0030] In this case, the outer surface of the first protective layer 150 may be substantially flat, and in this case, the outer surface of the printed circuit board according to an example may be substantially flat. However, this is not necessarily limited thereto, and the outer surface of the first protective layer 150 may be formed conformally along the shapes of the side surfaces of the first insulating layer 111 and the glass layer 110.

[0031] In addition, the first protective layer 150 of the printed circuit board according to an example may have a larger thermal expansion coefficient than the first insulating layer 111, and the first protective layer 150 may have a larger thermal expansion coefficient than the glass layer 110. Because the first protective layer 150 has a larger thermal expansion coefficient than the first insulating layer 111, the printed circuit board according to an example may prevent cracks generated in the glass layer 110 from growing. In addition, the first protective layer 150 may partially penetrate into cracks generated on the outer surface of the glass layer 110 during the singulation process into the unit substrate, thereby reducing the cracks, and compressive residual stress may be generated in the glass layer 110, thereby providing a double crack prevention function. In addition, since the outermost layer of the printed circuit board can be made of the first protective layer 150, it is possible to prevent external impacts from being directly applied to the glass layer 110, thereby preventing the glass layer 110 from breaking due to external impacts, and it is also possible to protect the first insulating layer 111 and the solder resist layer 140 from external impacts applied to the side surfaces of the first insulating layer 111 and the solder resist layer 140.

[0032] The first protective layer 150 may include an insulating material, such as an organic insulating material. The first protective layer 150 may include an underfill material, and known underfill materials may be used. The organic insulating material may also include a material used as a solder resist. The organic insulating material may include a thermosetting resin and an inorganic filler dispersed in the thermosetting resin, but may not include glass fiber. The insulating resin may be a photosensitive insulating resin or a resin such as epoxy. The filler may be an inorganic filler and / or an organic filler, but is not limited thereto. Other polymeric materials may also be used as needed. However, the first protective layer 150 is not limited thereto. Any material may be used for the first protective layer 150 as long as it has a high thermal expansion coefficient and can be formed on the side of the printed circuit board to protect the printed circuit board from damage. That is, the first protective layer 150 may be any material having a thermal expansion coefficient greater than those of the first insulating layer 111 and the glass layer 110.

[0033] In this case, the first protective layer 150 may include a material substantially different from that of the first insulating layer 111. The first insulating layer 111 is an insulating material used for interlayer insulation that insulates between the first wiring layers 121 of the printed circuit board, whereas the first protective layer 150 is not intended for interlayer insulation but for protecting the glass layer 110 and the first insulating layer 111, and so the first protective layer 150 may include a material substantially different from that of the first insulating layer 111.

[0034] Meanwhile, the first protective layer 150 may be formed by coating an insulating material in a liquid state and then curing it, but is not necessarily limited to this. In this case, the coating method may be any method that can form the first protective layer 150 on the outside of the printed circuit board, such as spraying or dipping, and is not necessarily limited to being formed by coating.

[0035] Meanwhile, the first protective layer 150 may include one or more protective layers. While FIG. 1 illustrates the first protective layer 150 as being a single layer, the present invention is not limited thereto and the first protective layer 150 may be composed of a plurality of first protective layers 150. When the first protective layer 150 is composed of a plurality of first protective layers 150, the plurality of first protective layers 150 may include substantially the same insulating material, but is not limited thereto and may include different insulating materials. When the first protective layer 150 includes a plurality of protective layers, the plurality of first protective layers 150 may be formed by forming one first protective layer 150 and then forming another first protective layer 150. In this case, the boundaries between the respective first protective layers 150 may be visible, but this is not necessarily limited thereto and the boundaries between the plurality of first protective layers 150 may be unclear. In this case, the boundaries between the plurality of first protective layers 150 may be confirmed by observing a cross section of the printed circuit board using a scanning microscope.

[0036] 1 shows the printed circuit board as being symmetrical with respect to the glass layer 110, but this is merely an illustration and is not necessarily limited to this. For example, the number of first insulating layers 111 located above the glass layer 110 may be different from the number of first insulating layers 111 located below the glass layer 110, the first wiring layers 121 located on the upper and lower surfaces of the glass layer 110 may be different from each other, or an asymmetric structure may be formed in which no first wiring layer 121 is located on one of the upper and lower surfaces of the glass layer 110.

[0037] Meanwhile, the printed circuit board according to the example is not limited to the configuration shown in Fig. 1, and may further include general components of a printed circuit board, or may omit some components. That is, it may further include components that can be utilized by a person having ordinary skill in the art.

[0038] FIG. 2 is a cross-sectional view schematically showing another example of a printed circuit board.

[0039] Another example of a printed circuit board further includes a second insulating layer 112 arranged on the first insulating layer 111, and a second wiring layer 122 arranged on the second insulating layer 112, and the average pitch of the second wiring layer 122 may be smaller than the average pitch of the first wiring layer 121.

[0040] According to another example, the printed circuit board may have an asymmetric structure in which the number of insulating layers stacked on the upper side of the glass layer 110 is not symmetrical to the number of insulating layers stacked on the lower side. Even if the upper and lower sides of the glass layer 110 are not symmetrical to each other, the printed circuit board can be protected from warping because stiffness can be ensured through the glass layer 110. However, the printed circuit board can be protected from warping even if the insulating materials of the first insulating layer 111 and the second insulating layer 112 have different compositions.

[0041] The second insulating layer 112 may be composed of one or more insulating layers and may include an organic insulating material. The organic insulating material may include a thermosetting resin such as an epoxy resin, a thermoplastic resin such as a polyimide, or a material containing a resin together with an inorganic filler, an organic filler, and / or glass fiber (glass fiber, glass cloth, glass fabric). For example, the insulating material may be a non-photosensitive insulating material such as ABF (Ajinomoto Build-up Film) or PPG (Prepreg), but is not limited thereto. Other polymeric materials may also be used. The insulating material may also be a photosensitive insulating material such as PID (Photo Imageable Dielectric). The insulating material may also include an adhesive sheet such as BS (Bonding Sheet). The second insulating layer 112 may be disposed on the first insulating layer 111, but is not necessarily limited thereto. The second insulating layer 112 may be directly laminated on the glass layer 110 so that the second insulating layer 112 is in contact with the glass layer 110.

[0042] The first insulating layer 111 and the second insulating layer 112 may contain different insulating materials. The first insulating layer 111 and the second insulating layer 112 may contain different insulating materials. This not only means that the first insulating layer 111 and the second insulating layer 112 contain different types of insulating materials from the group of insulating materials described above, but also means that the insulating material of the first insulating layer 111 may contain a material that is the same type of insulating material, but that has a composition and a composition ratio that is partially different from the composition and a composition ratio of the insulating material of the second insulating layer 112. For example, the first insulating layer 111 and the second insulating layer 112 may each contain Ajinomoto Build-up Film (ABF), but the composition contained in the first insulating layer 111 and the composition contained in the second insulating layer 112 may be partially different. That is, the first insulating layer 111 and the second insulating layer 112 each contain a filler, but the fillers may be different, so that the first insulating layer 111 and the second insulating layer 112 may contain different insulating materials. Alternatively, the filler contained in the second insulating layer 112 may have a finer structure than the filler contained in the first insulating layer 111. In this case, the filler may be an inorganic filler, but is not necessarily limited to this. The fact that the filler contained in the second insulating layer 112 is finer than the filler contained in the first insulating layer 111 may mean that the diameter, volume, etc. of the filler contained in the second insulating layer 112 is smaller than the diameter, volume, etc. of the filler contained in the first insulating layer 111. The second insulating layer 112 may contain a finer filler than the inorganic filler of the first insulating layer 111. Therefore, the second insulating layer 112 may be more advantageous for fine pattern processing than the first insulating layer 111, and the second wiring layer 122 disposed on the second insulating layer 112 may include finer wiring than the first wiring layer 121.

[0043] The fact that the fillers contained in the first insulating layer 111 and the second insulating layer 112 are different can be confirmed by analyzing a vertical cross-section of the printed circuit board. Each filler can be compared using a scanning microscope or optical microscope based on the polished or cut cross-section of the printed circuit board, and if necessary, the vertical cross-section can be stained to more easily identify the filler. The diameter of the filler can be measured using a scanning microscope or optical microscope based on the polished or cut cross-section of the printed circuit board, as described above, and the average value can be compared with the average value of values ​​measured at any five points.

[0044] The second wiring layer 122 may be composed of one or more wiring layers and may include a metal. Metals may include copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and / or alloys thereof. Preferably, but not limited to, copper (Cu). Each of the second wiring layers 122 may perform various functions depending on the design. For example, it may include a signal pattern, a power pattern, a ground pattern, etc. These patterns may each have various forms, such as a line, a plane, or a pad. The second wiring layer 122 may include an electroless plating layer (or chemical copper) and an electrolytic plating layer (or electrolytic copper). Alternatively, it may include a metal foil (or copper foil) and an electrolytic plating layer (or electrolytic copper). Alternatively, it may include a metal foil (or copper foil), an electroless plating layer (or chemical copper), and an electrolytic plating layer (or electrolytic copper). A sputtering layer may be included instead of the electroless plating layer (or chemical copper), or both may be included if necessary. The second wiring layer 122 may be disposed on the second insulating layer 112, but is not limited thereto, and may also be disposed directly on the upper surface and / or the lower surface of the glass layer 110.

[0045] The second wiring layer 121 may be formed by any one of SAP (Semi Additive Process), MSAP (Modified Semi Additive Process), TT (Tenting), or subtractive process, but is not limited thereto and may be formed by any process that can form a circuit on a printed circuit board. Also, without being limited thereto, the second wiring layer 121 may be formed by different processes depending on the application, design, etc.

[0046] The average pitch of the second wiring layer 122 may be smaller than the average pitch of the first wiring layer 121. In other words, the average distance between the wiring patterns of the second wiring layer 122 may be closer than the average distance between the wiring patterns of the first wiring layer 121, which may mean that the wiring density of the second wiring layer 122 is greater than the wiring density of the first wiring layer 121.

[0047] The average pitch of the second wiring layer 122 can be measured by photographing a cross section of the printed circuit board using a scanning microscope, and the average pitch can be the average value of the pitches between wirings measured at any five points. The average interlayer insulation distance can also be measured by photographing a cross section of the printed circuit board using a scanning microscope, and the average interlayer insulation distance can be the average value of the insulation distances between adjacent wiring layers above and below measured at any five points.

[0048] That is, the wiring included in the second wiring layer 122 may be high-density fine wiring with a smaller L / S (Line / Space) than the wiring included in the first wiring layer 121. As a non-limiting example, the wiring included in the second wiring layer 122 may have a line / space of about 2 / 2 μm, but is not limited to this. The high wiring density of the second wiring layer 122 may be effective in interconnecting electronic components such as semiconductor chips. That is, the second wiring layer 122 may be used as a redistribution layer for mounting semiconductor chips, etc.

[0049] Generally, a printed circuit board including a wiring layer with fine wiring often warps due to asymmetry of the board. However, since the printed circuit board according to another example includes a glass layer 110 with excellent rigidity, it is possible to prevent warpage due to asymmetry even if the wiring layer with fine wiring is formed only on one side of the board.

[0050] Meanwhile, a printed circuit board according to another example may further include a second via layer 132 penetrating at least a portion of the second insulating layer 112 to connect the second wiring layers 122 to each other. The second via layer 132 may include a metal. The metal may include copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), and / or alloys thereof. Preferably, the metal may include, but is not limited to, copper (Cu). The second via layer 132 may include filled vias that fill the respective via holes, but may also include conformal vias arranged along the wall surfaces of the via holes. The second via layer 132 may perform various functions depending on the design. For example, the second via layer 132 may include a ground via, a power via, a signal via, etc. Like the second wiring layer 122, the second via layer 132 may include an electroless plating layer (or chemical copper) and an electrolytic plating layer (or electrolytic copper). Alternatively, it may include a metal foil (or copper foil) and an electrolytically plated layer (or electrolytic copper). It may also include a sputtered layer instead of an electroless plated layer (or chemical copper), or it may include both if necessary.

[0051] The width of the second insulating layer 112 may be narrower than the width of the glass layer 110, or may be substantially the same as the width of the first insulating layer 111. This may be a result of performing a step of removing a portion of the second insulating layer 112 during the step of removing a portion of the first insulating layer 111 in a method for manufacturing a printed circuit board according to another example, and then performing a step of cutting the glass layer 110. Because the first insulating layer 111 and the second insulating layer 112 each include an organic insulating material, a step of removing a portion of the second insulating layer 112 during the step of removing a portion of the first insulating layer 111 may be performed.

[0052] The first protective layer 150 may cover at least a portion of the side surface of the second insulating layer 112. This may be the result of forming the first protective layer 150 after cutting the glass layer 110 and singulating it into unit substrates, and the first protective layer 150 may cover at least a portion of the side surface of the glass layer 110, a portion of the top and bottom surfaces of the glass layer 110, at least a portion of the side surface of the first insulating layer 111, and may extend to cover at least a portion of the side surface of the second insulating layer 112.

[0053] In the printed circuit board according to the other example, a solder resist layer 140 may be disposed on the second insulating layer 112. As in the printed circuit board according to the example, the first protective layer 150 may cover at least a portion of the side surface of the solder resist layer 140.

[0054] In another example of the printed circuit board shown in Figure 2, the description other than that relating to the second insulating layer 112 and the second wiring layer 122 can be applied in the same way as in the example of the printed circuit board, so duplicated description will be omitted.

[0055] FIG. 3 is a cross-sectional view schematically showing still another example of a printed circuit board.

[0056] According to yet another example, the printed circuit board may further include a second protective layer 160 disposed between the glass layer 110 and the first protective layer 150. The second protective layer 160 may contact at least a portion of the side surface of the glass layer 110, portions of the top and bottom surfaces of the glass layer 110, and at least a portion of the side surface of the first insulating layer 111. That is, the second protective layer 160 may be disposed between the glass layer 110 and the first protective layer and extend so as to be disposed between the side surface of the first insulating layer 111 and the first protective layer 150. The thermal expansion coefficient of the second protective layer 160 may be greater than the thermal expansion coefficient of the first insulating layer 111 and may be greater than the thermal expansion coefficient of the glass layer 110.

[0057] The second protective layer 160 may include an insulating material, such as an organic insulating material. The second protective layer 160 may function as a means for improving adhesion between the first protective layer 150 and the laminate of the printed circuit board. As a non-limiting example, the second protective layer 160 may include a resin such as epoxy, and the filler may be an inorganic filler and / or an organic filler, but is not limited thereto. Other polymeric materials may also be used as needed. Alternatively, the second protective layer 160 may include a bonding sheet or a coupling agent, and any material that ensures adhesion with the glass layer 110 or with the side of the first insulating layer 111 after lamination and curing may be used without limitation.

[0058] Meanwhile, the insulating material of the second protective layer 160 is not limited thereto, and the second protective layer 160 may include one material from the insulating material group of the first protective layer 150. That is, the second protective layer 160 may use an underfill material, and a known underfill material may be used. In addition, as described above in the description of the printed circuit board according to an example, the organic insulating material may also use a material used as a solder resist in some cases, and therefore, the same content will not be repeated.

[0059] Since the second protective layer 160 may be formed in a step different from the step of forming the first protective layer 150, the boundary between the first protective layer 150 and the second protective layer 160 can be observed by using a scanning microscope to cut the cross section of the printed circuit board. However, this is not limited thereto, and if the first protective layer 150 is formed immediately after the second protective layer 160 is formed, the boundary between the first protective layer 150 and the second protective layer 160 may not be clear. The method of forming the second protective layer 160 may be the same as the method of forming the first protective layer 150, but is not necessarily limited thereto, and the second protective layer 160 may be formed by various methods depending on the material of the second protective layer 160.

[0060] In this case, the second protective layer 160 may include one or more protective layers. While FIG. 3 illustrates the second protective layer 160 as being one layer, the present invention is not limited thereto and the second protective layer 160 may be configured with a plurality of second protective layers 160. When the second protective layer 160 is configured with a plurality of second protective layers 160, the plurality of second protective layers 160 may include substantially the same insulating material, but is not limited thereto and may include different insulating materials. Meanwhile, when the second protective layer 160 includes a plurality of protective layers, the plurality of second protective layers 160 may be formed by forming one second protective layer 160 and then forming another second protective layer 160. In this case, the boundaries between the respective second protective layers 160 may be visible, but this is not necessarily limited thereto and the boundaries between the plurality of second protective layers 160 may be unclear. In this case, the boundaries between the plurality of second protective layers 160 may be confirmed by observing the cross section of the printed circuit board using a scanning microscope.

[0061] In addition, the explanation other than the content regarding the presence or absence of the second protective layer 160 in the printed circuit board according to another example of Figure 3 can be applied in the same way as the explanation of the printed circuit board according to one example and the printed circuit board according to the other example, so duplicate explanations will be omitted.

[0062] FIG. 4 is a cross-sectional view schematically showing still another example of a printed circuit board.

[0063] According to yet another example, the printed circuit board may further include a third protective layer 170 disposed between the second protective layer 160 and the first protective layer 150. The third protective layer 170 may be disposed on the second protective layer 160 and conformally disposed along the boundary of the second protective layer 160. The third protective layer 170 may have a thermal expansion coefficient greater than that of the first insulating layer 111 and may have a thermal expansion coefficient greater than that of the glass layer 110. The third protective layer 170, like the first protective layer 150 and / or the second protective layer 160, may prevent cracks occurring in the glass layer 110 from growing. The third protective layer 170 may also increase adhesion between the second protective layer 160 and the first protective layer 150.

[0064] The third protective layer 170 may include an insulating material, such as an organic insulating material. The third protective layer 170 may include an underfill material, and known underfill materials may be used. The organic insulating material may also include a material used as a solder resist in some cases. The organic insulating material may include a thermosetting resin and an inorganic filler dispersed in the thermosetting resin, but may not include glass fiber. The insulating resin may be a photosensitive insulating resin or a resin such as epoxy. The filler may be an inorganic filler and / or an organic filler, but is not limited thereto. Other polymeric materials may also be used as needed. However, the third protective layer 170 is not limited thereto. The third protective layer 170 may be made of any material having a high thermal expansion coefficient and capable of protecting the printed circuit board from damage when formed on the side of the printed circuit board. That is, the third protective layer 170 may be made of any material having a thermal expansion coefficient greater than those of the first insulating layer 111 and the glass layer 110. Meanwhile, the third protective layer 170 may include substantially the same insulating material as the first protective layer 150, but is not limited thereto and may include different insulating materials. When the third protective layer 170 includes substantially the same insulating material as the first protective layer 150, the third protective layer 170 may have substantially the same thermal expansion coefficient as the first protective layer 150, but is not limited thereto and may have a thermal expansion coefficient smaller than that of the first protective layer 150. When the thermal expansion coefficient of the third protective layer 170 is larger than that of the first insulating layer 111 but smaller than that of the first protective layer 150, the third protective layer 170 may be provided as an intermediate layer between the first insulating layer 111 and the first protective layer 150. That is, the third protective layer 170 may serve to reduce the degree of thermal expansion of each of the first insulating layer 111 and the first protective layer 150.

[0065] Meanwhile, the third protective layer 170 may be formed by coating an insulating material in a liquid state and then curing it, but the method is not limited thereto. The coating method may be any method capable of forming the third protective layer 170 on the outside of the printed circuit board, such as spraying or dipping, and is not limited to coating. In addition, in the printed circuit board according to another example, the first protective layer 150 is formed after the third protective layer 170 is formed, but this is not limited thereto, and the boundary between the first protective layer 150 and the third protective layer 170 may be unclear. Meanwhile, in FIG. 4, the third protective layer 170 is formed on the second protective layer 160, but this is not limited thereto, and the second protective layer 160 may be omitted if necessary.

[0066] Meanwhile, in the printed circuit board according to another example of FIG. 4, the explanation other than the content regarding the presence or absence of the third protective layer 170 can be applied in the same manner as the explanation of the printed circuit board according to one example, the printed circuit board according to another example, and the printed circuit board according to yet another example, and therefore, duplicate explanations will be omitted.

[0067] <Printed Circuit Board Manufacturing Method> 5 to 8 are cross-sectional views that schematically show an example of a method for manufacturing a printed circuit board.

[0068] According to an example embodiment, a method for manufacturing a printed circuit board may include forming a large-area strip substrate in a panel unit and then singulating the strip substrate into each unit substrate. After the singulation step, a method for manufacturing a printed circuit board may include forming a first protective layer 150 on a side surface of the glass layer 110 and a side surface of the first insulating layer 111.

[0069] 5, the method includes forming a glass layer 110, a first insulating layer 111, a first wiring layer 121, and a solder resist layer 140. That is, the method may include forming a strip substrate for a panel unit including each unit substrate. At this time, the step of forming each component may be performed by a known method for forming a build-up structure of a printed circuit board.

[0070] Referring to FIG. 6 , the method may include a step of removing a portion of the first insulating layer 111. This is achieved by first removing a portion of the first insulating layer 111 before cutting the glass layer 110, prior to the singulation step. A portion of the first insulating layer 111 near a cutting line for singulating the unit substrates may be removed. The step of removing a portion of the first insulating layer 111 may be performed using, but is not limited to, a laser. As a non-limiting example, laser ablation may be used. However, the method of removing a portion of the first insulating layer 111 is not limited thereto, and other methods known to those skilled in the art, such as mechanical or chemical methods, may also be used. As a result of removing a portion of the first insulating layer 111, a portion of the upper surface and a portion of the lower surface of the glass layer 110 may be exposed to the outside, thereby exposing a cutting reference to the outside.

[0071] Referring to FIG. 7, the method may include cutting the glass layer 110 and dicing it into unit substrates. Dicing may be performed along a portion of the top surface and a portion of the bottom surface of the glass layer 110 exposed to the outside, and may be performed using a mechanical or chemical method. Non-limiting examples include sawing, laser processing, etching, or a combination of these methods. However, the method for processing and dicing the glass layer 110 is not limited thereto, and any method known to those skilled in the art may be used. Since the dicing of the glass layer 110 is performed after removing a portion of the first insulating layer 111, the width of the first insulating layer 111 may be narrower than the width of the glass layer 110, and the side surfaces of the first insulating layer 111 may not be coplanar with the side surfaces of the glass layer 110, or the side surfaces of the glass layer 110 may protrude beyond the side surfaces of the first insulating layer 111.

[0072] 8, the method may include forming a first protective layer 150 on the side surfaces of the glass layer 110. More specifically, the first protective layer 150 may be formed on at least a portion of the side surfaces of the glass layer 110, a portion of the top and bottom surfaces of the glass layer 110, and at least a portion of the side surfaces of the first insulating layer 111. The method of forming the first protective layer 150 may be, but is not limited to, a method of coating an insulating material in a liquid state and then curing it. In this case, the coating method may be any method that forms the first protective layer 150 on the outside of the printed circuit board, such as spraying or dipping. After the singulation into unit substrates, forming the first protective layer 150 on the side surfaces of each unit substrate may allow the side surfaces of the unit substrates to have substantially flat surfaces.

[0073] However, the present invention is not limited to the content depicted in the drawings, and may further include a method for forming a structure that can be used by a person having ordinary skill in the art. In addition, the method for manufacturing a printed circuit board according to another example and the method for manufacturing a printed circuit board according to a further example may also be performed by a method for forming a structure that can be used by a person having ordinary skill in the art, as described above with respect to the content of the printed circuit board according to another example and the printed circuit board according to a further example.

[0074] In the present disclosure, the terms "cover" and "enclose" may include not only "to cover entirely" but also "to cover at least partially," and may include not only "to cover directly" but also "to cover indirectly." Furthermore, the term "fill" may include not only "to fill completely" but also "to fill roughly," for example, including the presence of some gaps or voids.

[0075] In the present disclosure, "substantially" can be determined to include process errors, positional deviations, measurement errors, etc. that occur in the manufacturing process. For example, "substantially perpendicular" can include not only a case where the two are completely perpendicular, but also a case where the two are roughly perpendicular. Furthermore, "substantially coplanar" can include not only a case where the two are completely in the same plane, but also a case where the two are roughly in the same plane.

[0076] In this disclosure, the term "same insulating material" refers not only to the case where the insulating material is completely the same, but also to the case where the insulating material includes the same type of insulating material. Therefore, the composition of the insulating material is substantially the same, but the specific composition ratio may vary slightly. In this disclosure, the term "different insulating materials" refers to insulating materials that are not the same.

[0077] In the present disclosure, the meaning of "cross section" can mean the cross-sectional shape of an object cut vertically, or the cross-sectional shape of an object cut vertically, or the cross-sectional shape of an object when viewed from the side, and the meaning of "plane" can mean the planar shape of an object cut horizontally, or the planar shape of an object when viewed from the top or bottom.

[0078] In this disclosure, for convenience, terms such as lower, bottom, and lower surface are used to refer to the downward direction based on the cross section of the drawing, and terms such as upper, top, and upper surface are used to refer to the opposite direction. However, this is a definition of directions for convenience of explanation, and the scope of the claims is not particularly limited by the description of these directions, and the concepts of up and down can be changed at any time.

[0079] In this disclosure, the term "connected" encompasses not only direct connection but also indirect connection via an adhesive layer or the like. Furthermore, the term "electrically connected" encompasses both physical connection and non-physical connection. Furthermore, terms such as "first" and "second" are used to distinguish one component from another and do not limit the order and / or importance of the components. In some cases, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component, without departing from the scope of the invention.

[0080] The term "one example" used in this disclosure does not mean the same embodiment as the other examples, but is provided to emphasize and describe the unique features that are different from each other. However, the above-described one example does not exclude being realized in combination with the features of another example. For example, even if a matter described in a particular example is not described in another example, it can be understood as being related to the other example unless there is a contrary or contradictory description with that matter in the other example.

[0081] The terms used in this disclosure are merely used to describe an example and are not intended to limit the disclosure. In this case, singular expressions include plural expressions unless the context clearly indicates otherwise. [Explanation of symbols]

[0082] 110 Glass Layer 111 First insulating layer 112 Second insulating layer 121 1st wiring layer 122 2nd wiring layer 130 through vias 131 First via layer 132 Second via layer 140 Solder resist layer 150 1st protection layer 160 Second protective layer 170 Third protective layer

Claims

1. A glass layer; a first insulating layer disposed on the glass layer; a first wiring layer disposed on the first insulating layer; a first protective layer covering a portion of the top surface of the glass layer, at least a portion of a side surface of the glass layer, and at least a portion of a side surface of the first insulating layer.

2. The printed circuit board of claim 1 , wherein the first protective layer covers a portion of the lower surface of the glass layer.

3. further comprising a solder resist layer disposed on the first insulating layer; The printed circuit board according to claim 1 , wherein the first protective layer covers at least a part of a side surface of the solder resist layer.

4. The printed circuit board of claim 1 , wherein the first protective layer comprises a material that is substantially different from the first insulating layer.

5. the first insulating layer is disposed on an upper surface and a lower surface of the glass layer, The printed circuit board according to claim 1 , wherein the first wiring layer is disposed on each of the upper and lower surfaces of the glass layer.

6. a second insulating layer disposed on the first insulating layer; The printed circuit board of claim 1 , further comprising: a second wiring layer disposed on the second insulating layer.

7. The printed circuit board according to claim 6 , wherein the average pitch of the second wiring layer is smaller than the average pitch of the first wiring layer.

8. The printed circuit board according to claim 6 , wherein the first protective layer covers at least a portion of a side surface of the second insulating layer.

9. the width of the second insulating layer is substantially the same as the width of the first insulating layer; The printed circuit board of claim 8 , wherein the width of the second insulating layer and the width of the first insulating layer are smaller than the width of the glass layer.

10. The printed circuit board of claim 1 , further comprising one or more second protective layers disposed between the glass layer and the first protective layer.

11. The printed circuit board of claim 10 , wherein the second protective layer extends between at least a portion of a side surface of the first insulating layer and the first protective layer.

12. The printed circuit board of claim 10 , further comprising one or more third protective layers disposed between the second protective layer and the first protective layer.

13. The printed circuit board of claim 1 , wherein the first protective layer comprises one or more protective layers.

14. The printed circuit board of claim 1 , wherein the first protective layer has a coefficient of thermal expansion greater than the coefficient of thermal expansion of the first insulating layer.

15. The printed circuit board of claim 14 , wherein the first protective layer has a coefficient of thermal expansion greater than the coefficient of thermal expansion of the glass layer.

16. a second protective layer disposed between the first protective layer and the first insulating layer and between the first protective layer and the glass layer; The printed circuit board of claim 14 , wherein the second protective layer has a coefficient of thermal expansion greater than the coefficient of thermal expansion of the first insulating layer.

17. A glass layer; a first insulating layer disposed on the glass layer; a first wiring layer disposed on the first insulating layer; The width of the first insulating layer is smaller than the width of the glass layer.

18. 18. The printed circuit board of claim 17, further comprising a first protective layer covering a portion of the top surface of the glass layer, at least a portion of the side surface of the glass layer, and at least a portion of the side surface of the first insulating layer.

19. 20. The printed circuit board of claim 18, wherein the first protective layer covers a portion of the lower surface of the glass layer.

20. further comprising a solder resist layer disposed on the first insulating layer; The printed circuit board according to claim 18 , wherein the first protective layer covers at least a portion of a side surface of the solder resist layer.

21. 20. The printed circuit board of claim 18, wherein the first protective layer comprises a material that is substantially different from the first insulating layer.

22. a second insulating layer disposed on the first insulating layer; The printed circuit board of claim 17 , further comprising: a second wiring layer disposed on the second insulating layer.

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