Hole filling method and circuit board

Abstract

The invention discloses a hole filling method and a circuit board, and belongs to the technical field of microelectronics, and the hole filling method comprises the following steps: printing glass glaze slip at a through hole of a substrate, carrying out vacuum through hole processing, and then carrying out first sintering to form glass ground glaze at the through hole; and printing hole filling slurry at the through holes with the formed glass ground glaze, performing vacuum through hole forming, and then performing secondary sintering so as to form a conductive layer on the glass ground glaze. According to the hole filling method, the glass ground glaze is firstly formed in the through hole, the glass ground glaze can provide enough adhesive force for the conducting layer, in addition, vacuum hole through is carried out during printing, glass glaze slurry and hole filling slurry can be evenly spread on the inner wall of the through hole, and the adhesive force is further improved. Therefore, the hole filling method provided by the invention can solve the problem that the conductive material is easy to fall off and leave from the bottom in the existing printing hole filling method.

Description

Technical Field

[0001] The invention relates to the field of microelectronic technology, and in particular to a hole filling method and a circuit board. Background Art

[0002] The main function of through-holes in thick-film hybrid integrated circuits is to form electrical connections. On the one hand, they can establish electrical connections between different layers of the circuit board, and on the other hand, they can connect the leads of components (such as resistors, capacitors, diodes, etc.) to other parts of the circuit.

[0003] Conventional through-holes are mainly filled by electroplating, which involves first evaporating a seed layer at the through-hole, and then using pulse electroplating to thicken the metal inside the hole to achieve double-sided conduction. This electroplating filling method has problems such as low evaporation efficiency, high cost, difficulty in bath maintenance, and environmental pollution.

[0004] To this end, the prior art has a method of using a hole-filling slurry to print and fill holes, but this printing and filling method has the problem that the conductive material is easy to fall off and separate from the bottom. Summary of the invention

[0005] The main purpose of the present invention is to provide a hole filling method and a circuit board, aiming to solve the problem that the conductive material is easy to fall off and separate from the bottom in the existing printing hole filling method.

[0006] To achieve the above object, the hole filling method provided by the present invention comprises the following steps:

[0007] Printing glass glaze slurry at the through-holes of the substrate and performing vacuum through-hole processing, and then performing a first sintering to form a glass bottom glaze at the through-holes;

[0008] A hole filling paste is printed at the through hole formed with the glass base glaze, and vacuum through-hole is performed, and then a second firing is performed to form a conductive layer on the glass base glaze.

[0009] In one embodiment, the printing thickness of the glass glaze slurry is 0.05 μm-0.4 μm.

[0010] In one embodiment, the step of “printing glass glaze slurry at the through-holes of the substrate and performing vacuum through-holes” includes:

[0011] The substrate is fixed on the vacuum platform, and the through holes of the substrate are aligned with the holes of the vacuum platform, and then the glass glaze slurry is printed at the through holes.

[0012] In one embodiment, the glass glaze slurry includes the following components in percentage by weight:

[0013] Glass powder 40%-60%, first resin 1%-5%, first dispersant 0.5%-2%, first anti-settling agent 0.5%-2%, first leveling agent 0.1%-1%, first defoaming agent 0.1%-1%, and the balance is the first solvent.

[0014] In one embodiment, the glass powder includes at least one of silicon dioxide, calcium oxide, magnesium oxide, boron oxide, zirconium oxide, bismuth oxide, aluminum oxide, zinc oxide, copper oxide, and titanium dioxide; and / or,

[0015] The first resin includes at least one of ethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, rosin resin, terpene resin, polyester resin, and polyacrylic acid resin; and / or,

[0016] The first dispersant includes at least one of a hyperbranched polymer dispersant and a block copolymer dispersant; and / or,

[0017] The first anti-settling agent includes at least one of polyamide wax, organic bentonite, oxidized polyethylene wax, and fumed silica; and / or,

[0018] The first leveling agent includes at least one of an organic silicon leveling agent and an acrylic leveling agent; and / or,

[0019] The first defoamer includes at least one of an organic silicon defoamer and a non-silicon defoamer; and / or,

[0020] The first solvent includes at least one of diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, ethylene glycol butyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether, dipropylene glycol methyl ether, terpineol, and petroleum ether.

[0021] In one embodiment, the printing thickness of the hole filling paste is 3 μm-5 μm.

[0022] In one embodiment, the step of “printing a hole-filling paste at a through hole formed with a glass bottom glaze and performing vacuum through-hole forming” includes:

[0023] The substrate is fixed on the vacuum platform, and the through holes with glass bottom glaze formed on the substrate are aligned with the hole positions of the vacuum platform, and then the hole filling slurry is printed at the through holes.

[0024] In one embodiment, the hole filling slurry includes the following components in percentage by weight:

[0025] Metal powder 50%-80%, second resin 1%-5%, second dispersant 0.5%-2%, second anti-settling agent 0.5%-2%, second leveling agent 0.1%-1%, second defoaming agent 0.1%-1%, and the balance is second solvent.

[0026] In one embodiment, the metal powder includes at least one of platinum powder, gold powder, silver powder, and palladium powder; and / or,

[0027] The second resin includes at least one of ethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, rosin resin, terpene resin, polyester resin, and polyacrylic acid resin;

[0028] The second dispersant includes at least one of a hyperbranched polymer dispersant and a block copolymer dispersant; and / or,

[0029] The second anti-settling agent includes at least one of polyamide wax, organic bentonite, oxidized polyethylene wax, and fumed silica; and / or,

[0030] The second leveling agent includes at least one of an organic silicon leveling agent and an acrylic leveling agent; and / or,

[0031] The second defoamer includes at least one of an organic silicon defoamer and a non-silicon defoamer; and / or,

[0032] The second solvent includes at least one of diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, ethylene glycol butyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether, dipropylene glycol methyl ether, terpineol, and petroleum ether.

[0033] In one embodiment, the metal powder includes a first powder and a second powder, the particle size of the first powder is 1.0-3.0 μm, the particle size of the second powder is 0.1-1.0 μm, and the mass ratio of the first powder to the second powder is (3-5):1.

[0034] In one embodiment, the first sintering is performed at a temperature of 950° C. to 1000° C. for a time of 5 to 15 minutes.

[0035] In one embodiment, the second sintering is performed at a temperature of 1100° C.-1300° C. and for a time of 30-60 min.

[0036] The present invention also provides a circuit board, comprising a substrate, a through hole formed on the substrate, and a glass bottom glaze layer and a conductive metal layer sequentially arranged on the inner wall of the through hole.

[0037] The hole filling method of the present invention first forms a glass bottom glaze in the through hole, and the glass bottom glaze can provide sufficient adhesion for the conductive layer, and at the same time can reduce the sintering temperature of the hole filling slurry and improve the sintering density of the hole filling slurry. In addition, the hole filling method of the present invention performs vacuum hole filling during printing, so that the glass glaze slurry and the hole filling slurry can be evenly spread on the inner wall of the through hole, further improving the adhesion. Therefore, the hole filling method of the present invention can solve the problem that the conductive material is easy to fall off and separate from the bottom in the existing printing hole filling method. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the process of a hole filling method in one embodiment of the present invention. DETAILED DESCRIPTION

[0039] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. "At least one" appearing in the embodiments of the present invention refers to one or more, and "more than one" refers to two or more.

[0040] "Scope" disclosed in the present invention is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3,4 and 5 are listed, the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present invention, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0041] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] The existing method of filling holes by printing a filling paste includes the following steps: screen printing the filling paste on a substrate, drying, sequentially exposing, masking, developing, and sintering. The filling paste of the printing filling method is directly formed on the inner wall of the through hole, and there is a problem that the conductive material is easy to fall off and separate from the bottom.

[0043] To this end, the present invention provides a hole filling method, referring to Figure 1 As shown, the following steps are included:

[0044] Print glass glaze slurry at the through holes of the substrate and perform vacuum through-hole drilling, then perform the first sintering to form glass base glaze at the through holes; print hole filling slurry at the through holes formed with glass base glaze and perform vacuum through-hole drilling, then perform the second sintering to form a conductive layer on the glass base glaze.

[0045] Glass glaze slurry refers to a slurry mainly composed of a mixture of glass powder, additives and solvents, which can form a smooth and hard glaze layer after sintering. Hole-filling slurry refers to a slurry that can form a conductive layer at the through-hole. The volume of the hole-filling slurry will shrink during the sintering process, and the shrinkage direction points to the center of the hole. Therefore, the hole-filling slurry has a tendency to detach from the hole wall during sintering. The glass base glaze is first formed at the hole. On the one hand, the glass base glaze is between the hole-filling slurry and the substrate, which helps to reduce the surface tension of the hole-filling slurry and plays a role in wetting and spreading; on the other hand, the glass base glaze itself has good spreading, wetting and adhesion with the substrate, which can provide adhesion between the hole-filling slurry and the substrate.

[0046] Vacuum through-hole drilling refers to the process of sucking slurry into the through-hole under negative pressure conditions and extracting excess slurry, which can prevent excess slurry from accumulating in the hole and blocking the through-hole.

[0047] The hole filling method of the present invention first forms a glass bottom glaze in the through hole, and the glass bottom glaze can provide sufficient adhesion for the conductive layer, and at the same time can reduce the sintering temperature of the hole filling slurry and improve the sintering density of the hole filling slurry. In addition, the hole filling method of the present invention performs vacuum hole filling during printing, so that the glass glaze slurry and the hole filling slurry can be evenly spread on the inner wall of the through hole, further improving the adhesion. Therefore, the hole filling method of the present invention can solve the problem that the conductive material is easy to fall off and separate from the bottom in the existing printing hole filling method.

[0048] In addition, the present invention prints the paste directly at the through hole instead of printing the paste on the entire substrate surface, thereby eliminating the subsequent exposure and development process, and the method is simpler.

[0049] In an embodiment of the present invention, the printing thickness of the glass glaze slurry is 0.05 μm-0.4 μm.

[0050] When the glass glaze slurry is too thick, it wets the hole filling slurry more, which increases the sintering degree of the hole filling slurry and increases the shrinkage of the hole filling slurry. In addition, excessive glass glaze slurry on the substrate shows a dielectric constant and dielectric loss that are different from those of the substrate and the hole filling slurry, which has a great impact on the performance of some high-frequency electronic devices.

[0051] In an embodiment of the present invention, the step of "printing glass glaze slurry at the through holes of the substrate and performing vacuum through holes" includes: fixing the substrate on a vacuum platform, aligning the through holes of the substrate with the holes of the vacuum platform, and then printing glass glaze slurry at the through holes.

[0052] Fixing the substrate on the vacuum platform and aligning the through holes of the substrate with the holes of the vacuum platform includes: placing the substrate on the vacuum platform with corresponding holes, making the through holes on the substrate correspond to the holes on the vacuum platform one by one, and vacuuming the substrate to adsorb on the vacuum platform.

[0053] Printing the glass glaze slurry at the through hole can be done by screen printing, including: adding glass glaze slurry on the silk screen, printing the glass glaze slurry at the through hole by screen printing, and under the action of vacuum, the glass glaze slurry will enter the through hole along the edge of the through hole, and the excess glass glaze slurry in the hole will be sucked away by the vacuum and fall into the vacuum cavity, at this time, a uniform glass slurry layer can be formed on the inner wall of the through hole.

[0054] When screen printing is used, the aperture of the screen should be larger than the aperture of the through hole on the substrate. For example, when the aperture of the through hole on the substrate is 0.3 mm, the aperture of the screen can be selected to be 0.5 mm.

[0055] In an embodiment of the present invention, the glass glaze slurry includes the following components in percentage by mass:

[0056] Glass powder 40%-60%, first resin 1%-5%, first dispersant 0.5%-2%, first anti-settling agent 0.5%-2%, first leveling agent 0.1%-1%, first defoaming agent 0.1%-1%, and the balance is the first solvent.

[0057] The first resin, as a carrier, can bond other components in the glass glaze slurry and help maintain the predetermined shape and size of the print during the printing and drying process; the rheological properties of the first resin can also improve the printability of the glass glaze slurry.

[0058] The first dispersant can evenly disperse the components, thereby improving the consistency of the glass slurry; the first anti-settling agent is used to prevent the glass glaze slurry from settling or precipitating during storage, which can improve the uniformity and stability of the glass glaze slurry; the first leveling agent is used to improve the fluidity and spreadability of the glass glaze slurry, ensuring that the glass glaze slurry can be evenly distributed and dried after printing, thereby obtaining a smooth and defect-free glass base glaze; the first defoaming agent is used to help eliminate or reduce bubbles in the glass glaze slurry to ensure the quality and uniformity of the glass base glaze.

[0059] The glass glaze slurry of this embodiment has high consistency and stability, so that the formed glass base glaze is uniform and complete, ensuring that it has high adhesion to the hole filling slurry.

[0060] In an embodiment of the present invention, the glass powder includes at least one of silicon dioxide, calcium oxide, magnesium oxide, boron oxide, zirconium oxide, bismuth oxide, aluminum oxide, zinc oxide, copper oxide, and titanium dioxide; and / or, the first resin includes at least one of ethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, rosin resin, terpene resin, polyester resin, and polyacrylic resin; and / or, the first dispersant includes at least one of a hyperbranched polymer dispersant and a block copolymer dispersant; and / or, the first anti-settling agent includes a poly At least one of amide wax, organic bentonite, oxidized polyethylene wax, and fumed silica; and / or, the first leveling agent includes at least one of an organic silicone leveling agent and an acrylic leveling agent; and / or, the first defoaming agent includes at least one of an organic silicone defoaming agent and a non-silicon defoaming agent; and / or, the first solvent includes at least one of diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, ethylene glycol butyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether, dipropylene glycol methyl ether, pineneol, and petroleum ether.

[0061] The first dispersant may be selected from at least one of BYK-110, KD-1, TEGO 685 and TEGO 688. BYK-110, TEGO 685 and TEGO 688 are all dispersants based on polyacrylate copolymers, and KD-1 is a dispersant based on polyacrylate, polycarboxylate or other polymers.

[0062] The specific selection of the first leveling agent may be at least one of BYK-333, BYK-345, BYK-306, BYK-358N, and BYK-361N; BYK-333, BYK-345, BYK-306, BYK-358N, and BYK-361N are all silicone leveling agents, including modified siloxane polymers.

[0063] The first defoamer may be selected from at least one of BYK-012, BYK-014, BYK-1794, BYK-A550 and BYK-066N. BYK-012, BYK-014, BYK-1794, BYK-A550 and BYK-066N are all organic silicone leveling agents, including modified silicone oil.

[0064] In the embodiment of the present invention, the printing thickness of the hole filling paste is 3 μm-5 μm. This embodiment is thick film printing, that is, a thicker conductive layer is printed at the through hole.

[0065] In an embodiment of the present invention, the step of "printing a hole-filling slurry at a through hole formed with a glass bottom glaze and performing vacuum through-hole operation" includes: fixing the substrate on a vacuum platform, aligning the through hole formed with a glass bottom glaze on the substrate with the hole position of the vacuum platform, and then printing the hole-filling slurry at the through hole.

[0066] Fixing the substrate on the vacuum platform and aligning the through holes formed with the glass bottom glaze on the substrate with the hole positions of the vacuum platform includes: placing the substrate on the vacuum platform with corresponding hole positions, making the through holes formed with the glass bottom glaze on the substrate correspond one-to-one with the hole positions on the vacuum platform, and vacuuming to make the substrate adsorbed on the vacuum platform.

[0067] The hole-filling slurry can be printed at the through-hole by screen printing, including: adding the hole-filling slurry on the screen, and printing the hole-filling slurry on the glass bottom glaze of the through-hole by screen printing. Under the action of vacuum, the hole-filling slurry will enter the through-hole along the edge of the through-hole, and the excess hole-filling slurry in the hole will be sucked away by the vacuum and fall into the vacuum cavity. At this time, a uniform hole-filling slurry layer can be formed on the glass bottom glaze.

[0068] In an embodiment of the present invention, the hole filling slurry includes the following components in percentage by mass:

[0069] Metal powder 50%-80%, second resin 1%-5%, second dispersant 0.5%-2%, second anti-settling agent 0.5%-2%, second leveling agent 0.1%-1%, second defoaming agent 0.1%-1%, and the balance is second solvent.

[0070] The second resin, as a carrier, can bond other components in the pore-filling slurry and help maintain the predetermined shape and size of the print during the printing and drying process; the rheological properties of the second resin can also improve the printability of the pore-filling slurry.

[0071] The second dispersant can evenly disperse the components, thereby improving the consistency of the glass slurry; the second anti-settling agent is used to prevent the filling slurry from settling or precipitating during storage, which can improve the uniformity and stability of the filling slurry; the second leveling agent is used to improve the fluidity and spreadability of the filling slurry, ensuring that the filling slurry can be evenly distributed and dried after printing, thereby obtaining a flat, defect-free conductive layer; the second defoaming agent is used to help eliminate or reduce bubbles in the filling slurry to ensure the quality and uniformity of the conductive layer.

[0072] In an embodiment of the present invention, the metal powder includes at least one of platinum powder, gold powder, silver powder, and palladium powder; and / or, the second resin includes at least one of ethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, rosin resin, terpene resin, polyester resin, and polyacrylic resin; the second dispersant includes at least one of a hyperbranched polymer dispersant and a block copolymer dispersant; and / or, the second anti-settling agent includes at least one of polyamide wax, organic bentonite, oxidized polyethylene wax, and fumed silica; and / or, the second leveling agent includes at least one of an organic silicon leveling agent and an acrylic leveling agent; and / or, the second defoaming agent includes at least one of an organic silicon defoaming agent and a non-silicon defoaming agent; and / or, the second solvent includes at least one of diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, ethylene glycol butyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether, dipropylene glycol methyl ether, pinene alcohol, and petroleum ether.

[0073] The specific selection of the second dispersant may be at least one of BYK-110, KD-1, TEGO 685, and TEGO 688; BYK-110, TEGO 685, and TEGO 688 are all dispersants based on polyacrylate copolymers, and KD-1 is a dispersant based on polyacrylate, polycarboxylate, or other polymers.

[0074] The specific choice of the second leveling agent may be at least one of BYK-333, BYK-345, BYK-306, BYK-358N, and BYK-361N; BYK-333, BYK-345, BYK-306, BYK-358N, and BYK-361N are all silicone leveling agents, including modified siloxane polymers.

[0075] The specific selection of the second defoamer may be at least one of BYK-012, BYK-014, BYK-1794, BYK-A550, and BYK-066N; BYK-012, BYK-014, BYK-1794, BYK-A550, and BYK-066N are all silicone leveling agents, including modified silicone oil.

[0076] In an embodiment of the present invention, the metal powder includes a first powder and a second powder, the particle size of the first powder is 1.0-3.0 μm, the particle size of the second powder is 0.1-1.0 μm, and the mass ratio of the first powder to the second powder is (3-5):1.

[0077] In this embodiment, a first powder of micron size and a second powder of submicron size are mixed for use, which can improve the dispersion performance of the metal powder and can improve the density and conductivity after sintering.

[0078] In the embodiment of the present invention, the temperature of the first sintering is 950° C.-1000° C. and the time is 5-15 minutes. Such sintering conditions can form a dense glass base glaze to provide adhesion and wettability for the subsequent hole-filling slurry.

[0079] In the embodiment of the present invention, the temperature of the second sintering is 1100° C.-1300° C., and the time is 30-60 minutes. Such sintering conditions can form a dense conductive layer to make the through hole conductive from top to bottom.

[0080] The present invention also provides a circuit board, including a substrate, a through hole formed on the substrate, and a glass base glaze layer and a conductive metal layer are sequentially arranged on the inner wall of the through hole. The glass base glaze layer is specifically formed by printing and sintering a glass slurry, and the conductive metal layer is specifically formed by printing and sintering a hole filling slurry. The conductive layer at the through hole of the circuit board of the present invention has high bonding strength and is not easy to fall off.

[0081] The following describes the invention in conjunction with specific embodiments.

[0082] Example 1

[0083] A hole filling method comprises the following steps:

[0084] (1) placing a cleaned ceramic substrate on a vacuum platform with corresponding holes, making the through holes of the substrate correspond to the holes on the vacuum platform one by one, and applying vacuum to make the substrate adsorbed on the platform;

[0085] (2) adding glass glaze slurry on the screen, and slowly printing the glass glaze slurry to the position of the through hole by screen printing. Under the action of vacuum negative pressure, the glass glaze slurry enters the through hole along the edge of the through hole, and the excess glass glaze slurry in the hole is sucked away and falls into the vacuum chamber. At this time, a uniform layer of glass glaze slurry is formed on the inner wall of the through hole;

[0086] (3) placing the substrate in step (2) into a high temperature furnace for the first sintering, the sintering temperature is 950° C., the sintering time is 10 min, and after the sintering is completed, a glass bottom glaze is formed at the through hole, and the thickness of the glass bottom glaze is 0.4 μm;

[0087] (4) placing the substrate in step (3) on a vacuum platform with corresponding holes, and making the through holes with glass bottom glaze formed on the substrate correspond to the holes on the vacuum platform one by one, and applying vacuum to make the substrate adsorbed on the platform;

[0088] (5) Adding hole-filling slurry on the screen, using screen printing to slowly print the hole-filling slurry to the position of the through hole. Under the action of vacuum negative pressure, the hole-filling slurry enters the through hole along the edge of the through hole, and the excess hole-filling slurry in the hole is sucked away and falls into the vacuum chamber. At this time, a uniform layer of hole-filling slurry is formed on the glass bottom glaze;

[0089] (6) The substrate in step (5) is placed in a high-temperature furnace for a second sintering, the sintering temperature is 1100° C., and the sintering time is 60 min. After the sintering is completed, a conductive layer can be formed on the glass base glaze, and the thickness of the conductive layer is 4 μm.

[0090] The glass glaze slurry includes the following components in percentage by mass:

[0091] Glass powder 40%, hydroxyethyl cellulose 5%, BYK-110 0.5%, polyamide wax 0.5%, BYK-333 0.1%, BYK-012 0.1%, diethylene glycol ethyl ether 53.8%.

[0092] The glass powder includes the following components in percentage by mass:

[0093] Silicon dioxide 66%, bismuth oxide 5%, aluminum oxide 15%, magnesium oxide 5%, calcium oxide 5%, titanium dioxide 4%.

[0094] The hole filling slurry includes the following components in percentage by weight:

[0095] Platinum powder 70%, ethyl cellulose 5%, BYK-110 0.5%, polyamide wax 0.5%, BYK-333 0.1%, BYK-012 0.1%, diethylene glycol ethyl ether 23.8%.

[0096] Example 2

[0097] The difference from Example 1 is that the thickness of the glass bottom glaze in this example is 0.2 μm, and the remaining steps are the same as those in Example 1.

[0098] Example 3

[0099] The difference from Example 1 is that the thickness of the glass bottom glaze in this example is 0.1 μm, and the remaining steps are the same as those in Example 1.

[0100] Example 4

[0101] The difference from Example 1 is that the thickness of the glass bottom glaze in this example is 0.05 μm, and the remaining steps are the same as those in Example 1.

[0102] Example 5

[0103] Different from Example 1, in this embodiment, the sintering temperature in step (3) is 1000° C., and the remaining steps are the same as in Example 1.

[0104] Comparative Example 1

[0105] In this comparative example, the hole filling paste is directly printed at the through hole to form a conductive layer, which specifically includes the following steps:

[0106] (1) Fix the cleaned ceramic substrate on the operating platform;

[0107] (2) adding a hole-filling slurry to the screen, and slowly printing the hole-filling slurry to the position of the through hole of the substrate by screen printing;

[0108] (3) The substrate in step (2) is placed in a high-temperature furnace and sintered at 1100° C. for 60 min. After sintering, a conductive layer is formed on the glass base glaze, and the thickness of the conductive layer is 4 μm.

[0109] The composition of the hole filling slurry in this comparative example is the same as that in Example 1.

[0110] Comparative Example 2

[0111] In this comparative example, the hole filling slurry is directly printed at the through hole and a vacuum through hole is performed to form a conductive layer, which specifically includes the following steps:

[0112] (1) placing a cleaned ceramic substrate on a vacuum platform with corresponding holes, making the through holes of the substrate correspond to the holes on the vacuum platform one by one, and applying vacuum to make the substrate adsorbed on the platform;

[0113] (2) Adding hole-filling slurry on the screen, using screen printing to slowly print the hole-filling slurry to the position of the through hole. Under the action of vacuum negative pressure, the hole-filling slurry enters the through hole along the edge of the through hole, and the excess hole-filling slurry in the hole is sucked away and falls into the vacuum chamber. At this time, a uniform layer of hole-filling slurry is formed on the glass bottom glaze;

[0114] (3) The substrate in step (2) is placed in a high-temperature furnace and sintered at 1100° C. for 60 min. After sintering, a conductive layer is formed on the glass base glaze, and the thickness of the conductive layer is 4 μm.

[0115] The composition of the hole filling slurry in this comparative example is the same as that in Example 1.

[0116] Comparative Example 3

[0117] The difference from Example 1 is that the thickness of the glass bottom glaze in this comparative example is 6 μm, and the remaining steps are the same as those in Example 1.

[0118] Comparative Example 4

[0119] The difference from Example 1 is that the thickness of the glass bottom glaze in this comparative example is 0.01 μm, and the remaining steps are the same as those in Example 1.

[0120] Comparative Example 5

[0121] Different from Example 1, in this example, the sintering temperature in step (3) is 900° C., and the remaining steps are the same as in Example 1.

[0122] Comparative Example 6

[0123] Different from Example 1, in this embodiment, the sintering temperature in step (3) is 850° C., and the remaining steps are the same as in Example 1.

[0124] Performance Testing

[0125] The bonding strength of the conductive layer at the through hole in Examples 1-5 and Comparative Examples 1-6 was tested to specifically observe whether the conductive layer was detached after sintering and after ultrasonic treatment. The ultrasonic treatment was to put the substrate into an ultrasonic cleaning machine for ultrasonic treatment for 10 minutes and then take it out and dry it. The results are shown in Table 1.

[0126] Table 1 Pattern line width in Examples 1-5 and Comparative Examples 1-6

[0127]

[0128]

[0129] It can be seen from Table 1 that in Examples 1-5 of the present invention, no separation from the bottom occurs after the hole-filling slurry is sintered, and there is still no separation after ultrasonic treatment for 10 minutes, indicating that the method of the present invention of first forming a glass bottom glaze in the hole and then forming a conductive layer can significantly improve the bonding strength of the conductive layer.

[0130] It can be seen from the comparison of Examples 1-4 and Comparative Examples 4-5 that the thickness of the glass glaze slurry affects the bonding strength of the conductive layer finally formed. If the glass glaze slurry is too thick or too thin, the bonding strength of the conductive layer will be reduced. When the thickness of the glass glaze slurry is between 0.05μm and 0.4μm, the conductive coating does not separate from the bottom.

[0131] By comparing Examples 1, 5 and Comparative Examples 5-6, it can be seen that the first sintering temperature affects the bonding strength of the conductive coating. When the first sintering temperature is not higher than 900°C, the glass glaze slurry is insufficiently sintered, the thickness consistency is poor, and the areas that are particularly thin or thick are prone to detachment from the bottom.

[0132] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A hole filling method, characterized in that: The following steps are involved: Printing glass glaze slurry at the through-holes of the substrate and performing vacuum through-hole processing, and then performing a first sintering to form a glass bottom glaze at the through-holes; A hole filling paste is printed at the through hole formed with the glass base glaze, and vacuum through-hole is performed, and then a second firing is performed to form a conductive layer on the glass base glaze.

2. The hole filling method according to claim 1, characterized in that: The thickness of the glass base glaze is 0.05 μm-0.4 μm.

3. The hole filling method according to claim 1, characterized in that: The step of "printing glass glaze slurry at the through hole of the substrate and performing vacuum through hole" includes: The substrate is fixed on the vacuum platform, and the through holes on the substrate are aligned with the holes of the vacuum platform, and then the glass glaze slurry is printed at the through holes.

4. The hole filling method according to any one of claims 1 to 3, characterized in that: The glass glaze slurry comprises the following components in percentage by mass: Glass powder 40%-60%, first resin 1%-5%, first dispersant 0.5%-2%, first anti-settling agent 0.5%-2%, first leveling agent 0.1%-1%, first defoaming agent 0.1%-1%, and the balance is the first solvent.

5. The hole filling method according to claim 4, characterized in that: The glass powder includes at least one of silicon dioxide, calcium oxide, magnesium oxide, boron oxide, zirconium oxide, bismuth oxide, aluminum oxide, zinc oxide, copper oxide, and titanium dioxide; and / or, The first resin includes at least one of ethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, rosin resin, terpene resin, polyester resin, and polyacrylic acid resin; and / or, The first dispersant comprises at least one of a hyperbranched polymer dispersant and a block copolymer dispersant; and / or, The first anti-settling agent comprises at least one of polyamide wax, organic bentonite, oxidized polyethylene wax, and fumed silica; and / or, The first leveling agent includes at least one of an organic silicon leveling agent and an acrylic leveling agent; and / or, The first defoamer comprises at least one of an organic silicon defoamer and a non-silicon defoamer; and / or, The first solvent includes at least one of diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, ethylene glycol butyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether, dipropylene glycol methyl ether, terpineol, and petroleum ether.

6. The hole filling method according to claim 1, characterized in that: The thickness of the conductive layer is 3 μm-5 μm.

7. The hole filling method according to claim 1, characterized in that: The step of "printing a hole-filling slurry at a through hole formed with a glass bottom glaze and performing vacuum through-hole forming" includes: The substrate is fixed on the vacuum platform, and the through holes formed with the glass bottom glaze on the substrate are aligned with the hole positions of the vacuum platform, and then the hole filling slurry is printed at the through holes.

8. The hole filling method according to claim 1 or 7, characterized in that: The hole filling slurry includes the following components in percentage by mass: Metal powder 50%-80%, second resin 1%-5%, second dispersant 0.5%-2%, second anti-settling agent 0.5%-2%, second leveling agent 0.1%-1%, second defoaming agent 0.1%-1%, and the balance is second solvent.

9. The hole filling method according to claim 8, characterized in that: The metal powder includes at least one of platinum powder, gold powder, silver powder and palladium powder; and / or, The second resin includes at least one of ethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, rosin resin, terpene resin, polyester resin, and polyacrylic acid resin; The second dispersant comprises at least one of a hyperbranched polymer dispersant and a block copolymer dispersant; and / or, The second anti-settling agent comprises at least one of polyamide wax, organic bentonite, oxidized polyethylene wax, and fumed silica; and / or, The second leveling agent includes at least one of an organic silicon leveling agent and an acrylic leveling agent; and / or, The second defoamer comprises at least one of an organic silicon defoamer and a non-silicon defoamer; and / or, The second solvent includes at least one of diethylene glycol ethyl ether, diethylene glycol ethyl ether acetate, ethylene glycol butyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether, dipropylene glycol methyl ether, terpineol, and petroleum ether.

10. The hole filling method according to claim 8, characterized in that: The metal powder includes a first powder and a second powder, the particle size of the first powder is 1.0-3.0 μm, the particle size of the second powder is 0.1-1.0 μm, and the mass ratio of the first powder to the second powder is (3-5):

1.

11. The hole filling method according to claim 1, characterized in that: The temperature of the first sintering is 950° C.-1000° C., and the time is 5-15 minutes.

12. The hole filling method according to claim 1, characterized in that: The temperature of the second sintering is 1100° C.-1300° C., and the time is 30-60 minutes.

13. A circuit board, comprising a substrate, characterized in that: A through hole is formed on the substrate, and a glass bottom glaze layer and a conductive metal layer are sequentially arranged on the inner wall of the through hole.

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