A method for filling raw ceramic sheets, a method for manufacturing a co-fired ceramic substrate, and a co-fired ceramic substrate

Abstract

The present invention discloses a method for filling raw ceramic sheets, a method for manufacturing a co-fired ceramic substrate, and a co-fired ceramic substrate, wherein a metal leak plate and a silk screen are used to successively fill holes and print, which significantly reduces the probability of incomplete hole filling of raw ceramic sheets, and at the same time, even if the first filling is incomplete, it can be filled again by a supplementary printing layer to achieve a full filling effect, and the printed metal filler can effectively compensate for its volume shrinkage after sintering, forming an interlayer connection pad with an enlarged cross section, ensuring that the resistance of the interlayer connection of the co-fired ceramic substrate will not increase suddenly, thereby ensuring that the electrical properties of the co-fired ceramic substrate are stable. Therefore, the method of the present application has the advantages of easy operation of the process flow, easy control of process quality, high hole filling yield, and suitability for mass production.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a method for filling a green ceramic sheet, a method for manufacturing a co-fired ceramic substrate, and a co-fired ceramic substrate. Background Art

[0002] In LTCC (low temperature co-fired ceramic) and HTCC (high temperature co-fired ceramic) technologies, it is usually necessary to drill holes in the green ceramic sheet and fill the through holes with metal paste as the interconnection circuit between layers; Figure 1 As shown in FIG. 1 , on the one hand, during the hole filling process, due to the tension, the metal slurry is prone to produce concave on the surface, resulting in incomplete filling and filling defects 21; on the other hand, when the green ceramic sheet is removed after the hole filling, part of the metal slurry at the contact point between the lower surface of the through hole and the platform is prone to adhere to the platform, resulting in adhesion loss defects 22, which also results in incomplete filling and interlayer microcracks 23 after sintering. Figure 2 , 3 As shown; and, during the final sintering process of LTCC products, the metal paste in the hole usually shrinks to a large extent, and some components of the metal paste diffuse into the ceramic matrix, which can easily cause voids or faults in the silver material after sintering, resulting in micro cracks in the layer 24, such as Figure 2 , 3 As shown. The above are three common failure modes of hole filling, which seriously affect the reliability of circuit interconnection. Usually LTCC products contain thousands, tens of thousands, or even hundreds of thousands of interconnected holes. The failure of one hole can cause the product to be scrapped. Therefore, it is very necessary to adopt a low-cost, efficient and reliable process method to ensure the fullness and success rate of hole filling. Summary of the invention

[0003] The first purpose of the present application is to provide a method for filling a green ceramic sheet, which can overcome the shortcomings of the existing process and obtain a green ceramic sheet with higher metal connection reliability.

[0004] In order to achieve the above objectives, this application adopts the following technical solutions: The present application provides a method for filling a raw porcelain sheet, wherein a plurality of through holes are pre-opened on the raw porcelain sheet, and the filling method comprises the steps of filling the through holes of the raw porcelain sheet with a metal leak plate, and printing a layer of metal slurry at the through hole positions of the filled raw porcelain sheet with a silk screen, and the sum of the volumes of the metal slurry used for filling and printing is greater than the volume of the through holes.

[0005] In one embodiment, when filling the holes, the diameter of the leak plate holes on the metal leak plate is larger than the diameter of the through holes.

[0006] In one embodiment, the aperture of the leak plate holes on the metal leak plate is 10 um-40 um larger than the aperture of the upper surface of the through hole of the green ceramic sheet.

[0007] In one embodiment, the through holes, the leakage plate holes and the wire mesh holes on the wire mesh screen are concentric, and the aperture of the wire mesh holes on the wire mesh screen is larger than the aperture of the leakage plate holes.

[0008] In one embodiment, the aperture of the screen hole is 20um-100um larger than the aperture of the through hole of the raw ceramic sheet, the tension of the screen is 20N-35N, the film thickness of the screen is 6um-10um, and the mesh number of the screen is 250-500 mesh.

[0009] In one embodiment, the filling process is carried out on a printing platform. Before starting the filling, breathable paper is placed on the printing platform, and the raw porcelain sheet is placed on the breathable paper. A number of adsorption holes connected to a vacuum source are provided on the printing platform, and the raw porcelain sheet and breathable paper are vacuum adsorbed on the printing platform through the adsorption holes.

[0010] In one embodiment, the surface of the breathable paper in contact with the green ceramic sheet has a release film.

[0011] In one embodiment, the thickness of the breathable paper is 0.05 mm-0.5 mm, and the pore diameter of the breathable paper is 0.1 um-10 um.

[0012] In one embodiment, the filling method further comprises: S1: Cover a layer of breathable paper on the printing platform and place the raw ceramic sheet to be filled on the breathable paper; S2: suspending the metal drain plate above the raw porcelain sheet, aligning the drain plate holes on the metal drain plate with the through holes of the raw porcelain sheet one by one, and then lowering the metal drain plate until it fits with the raw porcelain sheet; S3: performing the first hole filling, using a scraper to squeeze the metal slurry into the through hole of the green ceramic sheet; S4: replacing the metal filter plate with the silk screen screen, and aligning the silk screen screen with the green ceramic sheet; S5: Printing is performed, using the scraper to continue printing the metal slurry on the surface of the filled hole to cover the pattern; S6: Take out the green ceramic piece and dry it in a drying oven.

[0013] In one embodiment, in step S3, the process conditions for filling the holes of the metal leak plate are: the viscosity of the metal slurry is 200Pa·s-600Pa·s, the solid content of the slurry is 70%-95%; the pressure of the scraper is 0.1MPa-0.2MPa, the scraper angle is 60°-80°, and the scraper speed is 20mm / s-50mm / s.

[0014] In one embodiment, in step S5, the process conditions of screen printing include: the viscosity of the metal slurry is 100Pa·s-500Pa·s, and the solid content of the slurry is 65%-90%; the scraper pressure is 0.05MPa-0.1MPa, the scraper angle is 60°-80°, and the scraper speed is 40mm / s-80mm / s.

[0015] In one embodiment, in step S6, the drying oven temperature is 50° C.-80° C., and the drying time is 2 min-10 min.

[0016] In one embodiment, the thickness of the green ceramic sheet is in the range of 50um-150um; the size of the green ceramic sheet is in the range of a rectangle or polygon with a side length of 150mm-400mm; and the aperture of the through hole is in the range of 70um-300um.

[0017] The second objective of the present application is to provide a method for manufacturing a co-fired ceramic substrate, which can improve the production yield of the co-fired ceramic substrate.

[0018] The present application provides a method for manufacturing a co-fired ceramic substrate, comprising: Selecting a plurality of raw porcelain sheets, each of which is provided with a plurality of through holes; Filling the through holes on the green ceramic sheet using any of the filling methods described above; Stacking a number of filled green ceramic sheets; The co-fired ceramic substrate is formed through sintering.

[0019] Since the above-mentioned method of filling raw ceramic sheets is adopted, a raw ceramic sheet with a filling volume greater than the through-hole volume can be obtained. After multi-layer stacking and co-firing, even if the filling metal shrinks, a fully filled co-fired ceramic substrate can still be obtained. Therefore, the technical solution proposed can improve the yield rate of the co-fired ceramic substrate.

[0020] A third object of the present application is to provide a co-fired ceramic substrate having a reliable interlayer connection structure and stability.

[0021] To achieve the above-mentioned purpose, the present application also provides a co-fired ceramic substrate obtained according to the manufacturing method of the co-fired ceramic substrate, comprising a plurality of stacked substrates, wires filled in the through holes of each of the substrates, and interlayer connecting pads between the corresponding wires in two adjacent layers of substrates, and the width of the interlayer connecting pads is greater than the width of the wires.

[0022] In a possible implementation, the interlayer connection pad and the conductive wire are made of the same metal material.

[0023] In a possible implementation, the metal material is one or more of silver, copper, tungsten, gold, palladium and alloys thereof.

[0024] Understandably, the present application uses a metal leak plate and a silk screen for printing twice, which significantly reduces the probability of incomplete filling. At the same time, even if the first filling is incomplete, it can be filled again by the supplementary printing layer to achieve the effect of full filling. The printing layer can effectively compensate for its volume shrinkage after sintering, and at the same time, the filling fullness and interlayer interconnection reliability are greatly improved. In the manufacturing process of the raw ceramic sheet and co-fired ceramic substrate of the present application, there is no need to invest in additional equipment or customized tooling, nor is there any need to move or process the raw ceramic sheet after the hole is filled for a second time, which reduces the risk of deformation during the process; therefore, the method of the present application has the advantages of easy operation of the process flow, easy control of process quality, high hole filling yield, and suitability for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of defects in filling metal in green ceramic sheets in the prior art.

[0026] Figure 2 This is a schematic diagram of insufficient filling of metal slurry, resulting in a poor co-fired ceramic substrate.

[0027] Figure 3 Schematic diagram of the defective co-fired ceramic substrate caused by metal paste shrinkage.

[0028] Figure 4 It is a schematic flow chart of a method for manufacturing a co-fired ceramic substrate provided in one embodiment of the present application.

[0029] Figure 5 A schematic diagram of a co-fired ceramic substrate provided in one embodiment of the present application.

[0030] Figure 6 This is a schematic diagram of a printing platform provided in one embodiment of the present application.

[0031] Figure 7 A schematic diagram of a porous ceramic printing platform provided in one embodiment of the present application.

[0032] Figure 8 A schematic diagram of a first printing process provided in one embodiment of the present application.

[0033] Fig. 9 A schematic diagram of a second printing process provided in one embodiment of the present application.

[0034] Fig.10 Schematic diagram of the internal structure of the co-fired ceramic substrate in the related technology.

[0035] Fig.11 This is a schematic diagram of the internal structure of a co-fired ceramic substrate provided in one embodiment of the present application.

[0036] Among them: 10. Raw ceramic sheet; 11. Through hole; 20. Metal slurry; 21. Filling defect; 22. Adhesion loss defect; 23. Interlayer microcracks; 24. Intralayer microcracks; 25. Printing layer; 30. Co-fired ceramic substrate; 31. Base sheet; 32. Wire; 33. Interlayer connecting pad; 41. Printing platform; 42. Porous ceramic printing platform; 43. Adsorption hole; 5. Breathable paper; 61. Metal leak plate; 62. Silk screen; 7. Scraper; 81. Leak plate hole, 82. Silk screen hole; 9. Metal slurry. DETAILED DESCRIPTION

[0037] To describe the technical content, structural features, achieved purpose and effect of the invention in detail, the technical scheme in the embodiment of the present application will be described below in conjunction with the drawings in the embodiment of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, rather than all the embodiments. In the following description, for the purpose of explanation, many specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments may also be implemented without these specific details or in the case of one or more equivalent arrangements. In addition, various exemplary embodiments may be different, but not necessarily exclusive. For example, without departing from the inventive concept, the specific shape, structure and characteristics of the exemplary embodiment may be used or implemented in another exemplary embodiment.

[0038] In order to improve the problem of incomplete filling of raw porcelain sheets in the prior art, the applicant has successively adopted three processes to fill the holes in the raw porcelain sheets.

[0039] 1. Screen printing process: A layer of metal slurry is printed on the surface of the green ceramic sheet through a printing machine and a screen to achieve the effect of filling the through hole. However, the applicant found that the filling amount (i.e. the amount of ink applied by the screen) is related to the thickness of the film (the photosensitive film on the screen), which is only suitable for filling very thin green ceramic sheets, and is not suitable for filling holes in many medium-thick green ceramic sheets.

[0040] 2. Vacuum grouting process: By covering the steel plate mask on the raw ceramic sheet, the metal slurry coated on the steel plate is sucked into the hole by using a large vacuum suction force. However, in practice, the raw ceramic sheet and the platform cannot be absolutely overlapped. The raw ceramic sheet can easily penetrate into the gap under the action of vacuum, causing pollution and scrapping of the raw ceramic sheet, and the yield rate cannot be significantly improved.

[0041] 3. Leakage pressure process: Cover the steel plate mask on the raw ceramic sheet, leaving a certain gap, fill the slurry into the hole with a scraper, and form a bulge of a certain height; then use special equipment to flatten and scrape off the raised slurry. It also has defects: the flattening and scraping process depends on additional process equipment; and when pressure is applied to the raw ceramic sheet, it will cause anisotropic deformation around the hole and the whole raw ceramic sheet, resulting in reduced product quality and yield.

[0042] In addition, during the ceramic sintering process, multiple raw ceramic sheets need to be stacked and then sintered. Due to the stacking error of the multiple layers of raw ceramic sheets, the via alignment deviation occurs, and the resulting degradation of electrical performance, including excessive resistance, impedance discontinuity, parasitic effects, etc.

[0043] See also Fig.10 As shown in the figure, due to the mechanical error of the stacking equipment, the error of the via processing position, the deformation and expansion and contraction of the raw ceramic sheet, the alignment deviation of the vias stacked between the layers is inevitable. This deviation causes the cross-sectional area of ​​the conductive metal to suddenly decrease at the interconnection between the via of one raw ceramic substrate and the via of the adjacent substrate, that is, the resistance at this location suddenly increases. This situation may lead to a large resistance of the entire circuit, impedance discontinuity and parasitic effects at the interface, which will have an adverse effect on the high-frequency performance, signal transmission performance, current carrying performance, etc. of the co-fired ceramic substrate products.

[0044] After the above improvements and explorations, the applicant further proposed a method of filling the raw ceramic sheet by printing twice, specifically: using a metal leak plate to fill the through-holes of the raw ceramic sheet, and then using a silk screen to print one or more layers of metal paste (multi-layers include two or more layers) at the through-hole positions of the filled raw ceramic sheet, and making the sum of the volumes of the metal paste used for filling and printing greater than the volume of the through-hole. This can reduce the incidence of incomplete filling defects on the one hand, and effectively compensate for the volume shrinkage formed after the metal paste is sintered on the other hand, greatly improving the reliability of circuit interconnection.

[0045] In the preferred embodiment of the present application, the area of ​​the metal paste of the printed layer is larger than the area of ​​the filled hole, so that when the ceramic substrate is sintered, an interlayer connection pad with a larger cross-section can be formed. Fig.11As shown. Even if there are still unfavorable factors such as mechanical errors of stacking equipment, errors in via processing position, deformation and expansion of raw ceramic sheets, by increasing the printing of interlayer connection pads, it can be ensured that the resistance at the connection will not increase suddenly, ensuring that the high-frequency performance, signal transmission performance, and current-carrying performance of the co-fired ceramic substrate products still meet the design. In addition, the diameter of the interlayer connection pad can be set according to the process accuracy and control capabilities of the assembly line to ensure that the interlayer connection pad can completely cover the via metal of the adjacent raw ceramic sheet.

[0046] See also Figure 4 , 8 9. In one embodiment, the method for filling the green ceramic sheet comprises: S1: Cover the printing platform 41 with a layer of breathable paper 5, and place the green ceramic sheet 10 to be filled with holes on the breathable paper 5; S2: suspending the metal drain plate 61 above the green ceramic sheet 10, aligning the drain plate holes 81 on the metal drain plate 61 with the through holes 11 of the green ceramic sheet 10 one by one, and then lowering the metal drain plate 61 until it is in contact with the green ceramic sheet 10; S3: Filling the hole, using a scraper 7 to squeeze the metal slurry 9 into the through hole 11 of the green ceramic sheet 10; S4: Replace the metal filter plate 61 with the silk screen screen 62, and align the silk screen screen 62 with the green ceramic sheet 10. Alignment marks may be used. Finally, it is necessary to ensure that the silk screen holes 82 on the silk screen screen 62 are aligned with the printing position (concentric with the through hole 11) on the green ceramic sheet 10. S5: Printing is performed, using the scraper 7 to continue printing the metal paste 9 on the surface of the filled holes, that is, the metal paste 9 is covered with another layer of paste on the surface of the filled holes; S6: Take out the green ceramic piece 10 and dry it in a drying oven.

[0047] In one embodiment, during the first hole filling, the diameter of the drain plate hole 81 on the metal drain plate 61 is larger than the diameter of the through hole 11 to ensure that the metal slurry fills the through hole as much as possible.

[0048] In one embodiment, the diameter of the drain plate hole 81 on the metal drain plate 61 is 10 um to 40 um larger than the diameter of the upper surface of the through hole 11 of the green ceramic sheet 10 .

[0049] In one embodiment, the through hole 11, the leak plate hole 81 and the screen hole 82 on the screen plate 62 are concentric, and the aperture of the screen hole 82 on the screen plate is larger than the aperture of the leak plate hole 81, so that the metal paste can form an overfill at the through hole 11 and at the same time form a printed layer 25 larger than the through hole diameter.

[0050] In one embodiment, the aperture of the screen hole 82 is 20um-100um larger than the aperture of the through hole of the green ceramic sheet. The tension of the screen screen 62 is: 20N-35N. The film thickness of the screen screen 62 is: 6um-10um. The mesh number of the screen screen 62 is: 250-500 mesh.

[0051] In one embodiment, the entire filling process is performed on the printing platform 41 , and a vacuum suction force is provided on the printing platform 41 so that the green ceramic sheet is adsorbed and fixed on the surface of the printing platform. Figure 4 In the embodiment shown, a plurality of suction holes 43 connected to a vacuum source are provided on the printing platform 41 to suction and fix the objects on the printing platform. Figure 5 In the illustrated embodiment, the printing platform is a porous ceramic printing platform 42 having a plurality of fine adsorption holes, which also fix the objects placed on the platform by vacuum adsorption.

[0052] At the same time, in order to reduce the adhesion of the metal slurry 20 to the printing platform when the raw ceramic sheet 10 is separated from the printing platform 41, the present application also places a breathable paper 5 on the printing platform before starting filling, and places the raw ceramic sheet 10 on the breathable paper 5. The raw ceramic sheet 10 and the breathable paper 5 are vacuum adsorbed on the printing platform through a number of adsorption holes.

[0053] In one embodiment, the thickness of the breathable paper is 0.05 mm-0.5 mm, and the pore diameter of the breathable paper is 0.1 um-10 um.

[0054] In a preferred embodiment, the surface of the breathable paper 5 that contacts the green ceramic sheet 10 has a release film, and the release film can help the metal slurry to separate from the breathable paper without sticking.

[0055] The metal paste used in the present application may be silver paste, copper paste, tungsten paste, gold paste, palladium paste or alloy paste thereof.

[0056] In one possible implementation, in step S3, the process conditions for filling the metal leak plate are: the viscosity of the metal slurry is 200Pa·s-600Pa·s, and the solid content of the slurry is 70%-95%; the scraper pressure is 0.1MPa-0.2MPa, the scraper angle is 60°-80°, and the scraper speed is 20mm / s-50mm / s.

[0057] In a possible implementation, in step S5, the process conditions of screen printing include: the viscosity of the metal slurry is 100Pa·s-500Pa·s, and the solid content of the slurry is 65%-90%; the scraper pressure is 0.05MPa-0.1MPa, the scraper angle is 60°-80°, and the scraper speed is 40mm / s-80mm / s.

[0058] In a possible implementation, in step S6, the temperature of the drying oven is 50° C.-80° C., and the drying time is 2 min-10 min.

[0059] In a possible implementation, the thickness of the green ceramic sheet is in the range of 50um-150um; the size of the green ceramic sheet is in the range of a rectangle or polygon with a side length of 150mm-400mm; and the aperture of the through hole is in the range of 70um-300um.

[0060] An example of using a printing press to fill holes in a square green ceramic sheet with a size of 203 mm × 203 mm and a thickness of 0.1 mm is used for explanation.

[0061] The processing steps are divided into: S1: Select a porous ceramic printing platform, cover the printing platform with a layer of breathable paper, and place the raw ceramic sheet to be filled with holes on the breathable paper. The diameter of the pores of the porous ceramic printing platform is 40-50um; the thickness of the breathable paper is 0.1mm, and the pore diameter is 5um.

[0062] S2: Suspend the stainless steel leak plate above the raw ceramic sheet, align the holes on the stainless steel leak plate with the through holes of the raw ceramic sheet by positioning means, and then lower the stainless steel leak plate to a set height of -0.2mm relative to the upper surface of the printing platform; the aperture of the stainless steel leak plate is 40um larger than the aperture of the upper surface of the through hole of the raw ceramic sheet, and the thickness of the stainless steel leak plate is 0.5mm.

[0063] S3: Use a printing press to fill the holes, that is, the scraper is pressed down to fit the stainless steel plate, and the metal slurry (that is, silver paste) is squeezed into the through-holes of the green ceramic sheet. The viscosity of the metal slurry is 450Pa·s, and the solid content of the slurry is 87%; the scraper pressure is 0.1MPa, the scraper angle is 75°, and the scraper speed is 40mm / s.

[0064] S4: Replace the stainless steel plate with a silk screen, and align the silk screen with the mesh holes and through-holes of the green ceramic sheet. The pattern of the silk screen is a solid circle with the same position as the through-holes of the green ceramic sheet. The diameter of the circle is 60um larger than the hole diameter of the green ceramic sheet. The tension of the screen is 30N, the film thickness of the screen is 8um, and the mesh number of the screen is 400 meshes.

[0065] S5: Use a printing press to print, press the screen with a scraper and fit the green tile, and print a circular pattern on the surface of the green tile with filled holes. The viscosity of the metal slurry is 300 Pa·s, and the solid content of the metal slurry is 75%; scraper pressure: 0.05MPa, scraper angle: 75°, scraper speed: 70mm / s.

[0066] S6: Take out the green ceramic piece and dry it in a drying oven. The temperature of the drying oven is maintained at 60° C. and the drying time is 10 minutes.

[0067] The solution of the present invention adopts filling and printing. First, by improving the printing conditions and the improved metal leak plate, contact filling is performed to ensure that the metal paste will not have the risk of leakage and overflow. Then, by adding a printing layer on the filled through hole, the fullness of the metal paste filling in the through hole can be ensured, and at the same time, a printing layer 25 with a larger area is formed on the surface of the filled hole, further improving the reliability of the circuit interconnection between layers.

[0068] In addition, in one embodiment of the present application, a method for manufacturing a co-fired ceramic substrate is provided, comprising: Selecting a plurality of raw porcelain sheets, each of which is provided with a plurality of through holes; Filling the through holes on the green ceramic sheet twice using the aforementioned filling method; Then stack several filled raw porcelain pieces; Finally, the co-fired ceramic substrate is formed through sintering.

[0069] like Figure 5 As shown, the co-fired ceramic substrate 30 obtained by the manufacturing method of the present application includes a plurality of stacked substrates 31, wires 32 filled in the through holes of each substrate 31, and an interlayer connection pad 33 between the corresponding wires 32 in two adjacent substrates 31, and the width of the interlayer connection pad 33 is greater than the width of the wire 32. Among them, the substrate is formed by sintering the green ceramic sheet, the wire is formed by co-firing the metal slurry and the green ceramic sheet under the same conditions, and the interlayer connection pad is formed by the printed layer.

[0070] The printed layer 25 is a layer of metal paste printed on the incomplete hole filling surface by screen printing, thereby forming a layer of structure that is specially printed to improve the hole filling fullness and interlayer connection reliability. The interlayer connection pad 33 is an interlayer conductive structure formed by the printed layer 3 after the multi-layer raw ceramic sheets are stacked and sintered, such as Fig.11 As shown, since the cross-sectional area of ​​the metal wire at the interlayer connection pad 33 is increased, the resistance R there is smaller than the resistance of the wires at the upper and lower sides.

[0071] The interlayer connection pads 33 and the wires 32 are made of the same metal material. Specifically, the metal material may be one or more of silver, copper, tungsten, gold, palladium and alloys thereof.

[0072] The present invention can solve: In the process of filling holes in green ceramic sheets, the problem of incomplete filling and via alignment error caused by stacking may affect the reliability of circuit interconnection; The problem of metal slurry overflow that may occur during the hole filling process of green ceramic sheets; The existing hole filling technology relies on additional process equipment and has complex procedures; The existing technical solutions have the problems of insufficient hole filling yield and difficult quality control.

[0073] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and the scope of protection of the present invention is defined by the attached claims, description and their equivalents.

Claims

1. A method for filling a raw porcelain sheet, wherein a plurality of through holes are pre-opened on the raw porcelain sheet, characterized in that: The filling method includes the steps of filling the through holes of the raw ceramic sheet with a metal leak plate, and printing one or more layers of metal slurry on the through hole positions of the filled raw ceramic sheet with a silk screen, and the sum of the volumes of the metal slurry used for filling and printing is greater than the volume of the through hole.

2. The filling method according to claim 1, characterized in that: When filling the holes, the aperture of the leak plate holes on the metal leak plate is larger than the aperture of the through hole.

3. The filling method according to claim 2, characterized in that: The aperture of the leak plate holes on the metal leak plate is 10um-40um larger than the aperture of the upper surface of the through hole of the raw porcelain sheet.

4. The filling method according to claim 2, characterized in that: The through holes, the holes in the leakage plate and the screen holes on the screen screen are concentric, and the aperture of the screen holes on the screen screen is larger than the aperture of the holes in the leakage plate.

5. The filling method according to claim 4, characterized in that: The aperture of the screen hole is 20um-100um larger than the aperture of the through hole of the raw ceramic sheet, the tension of the screen plate is 20N-35N, the film thickness of the screen plate is 6um-10um, and the mesh number of the screen plate is 250-500 meshes.

6. The filling method according to claim 1, characterized in that: The filling process is carried out on a printing platform. Before starting the filling, a breathable paper is placed on the printing platform, and the raw porcelain sheet is placed on the breathable paper. A number of adsorption holes connected to a vacuum source are provided on the printing platform, and the raw porcelain sheet and the breathable paper are vacuum adsorbed on the printing platform through the adsorption holes.

7. The filling method according to claim 6, characterized in that: The surface of the air-permeable paper in contact with the green porcelain sheet is provided with a release film.

8. The filling method according to claim 6, characterized in that: The thickness of the breathable paper is: 0.05mm-0.5mm, the pore diameter of breathable paper is: 0.1um-10um.

9. The filling method according to claim 1, characterized in that: Also includes: S1: Cover a layer of breathable paper on the printing platform and place the raw ceramic sheet to be filled on the breathable paper; S2: suspending the metal drain plate above the raw porcelain sheet, aligning the drain plate holes on the metal drain plate with the through holes of the raw porcelain sheet one by one, and then lowering the metal drain plate until it fits with the raw porcelain sheet; S3: performing the first hole filling, using a scraper to squeeze the metal slurry into the through hole of the green ceramic sheet; S4: replacing the metal filter plate with the silk screen screen, and aligning the silk screen screen with the green ceramic sheet; S5: Printing is performed, using the scraper to continue printing the metal slurry on the surface of the filled hole to cover the pattern; S6: Take out the green ceramic piece and dry it in a drying oven.

10. The filling method according to claim 9, characterized in that: In step S3, the process conditions for filling the metal leak plate are as follows: the viscosity of the metal slurry is 200Pa·s-600Pa·s, the solid content of the slurry is 70%-95%; the pressure of the scraper is 0.1MPa-0.2MPa, the angle of the scraper is 60°-80°, and the speed of the scraper is 20mm / s-50mm / s.

11. The filling method according to claim 10, characterized in that: In step S5, the process conditions of screen printing include: the viscosity of the metal slurry is 100Pa·s-500Pa·s, the solid content of the slurry is 65%-90%; the scraper pressure is 0.05MPa-0.1MPa, the scraper angle is 60°-80°, and the scraper speed is 40mm / s-80mm / s.

12. The filling method according to claim 9, characterized in that: In step S6, the drying oven temperature is between 50°C and 80°C, and the drying time is between 2 min and 10 min.

13. The filling method according to any one of claims 1 to 12, characterized in that: The thickness of the green ceramic sheet is in the range of 50um-150um; the size of the green ceramic sheet is in the range of a rectangle or polygon with a side length of 150mm-400mm; the aperture of the through hole is in the range of 70um-300um.

14. A method for manufacturing a co-fired ceramic substrate, characterized in that: include: Selecting a plurality of raw porcelain sheets, each of which is provided with a plurality of through holes; Filling the through holes on the green ceramic sheet using the filling method as described in any one of claims 1 to 13; Stacking a number of filled green ceramic sheets; The co-fired ceramic substrate is formed through sintering.

15. The co-fired ceramic substrate obtained by the manufacturing method according to claim 14, characterized in that: It comprises a plurality of stacked substrates, conductive wires filled in through holes of the substrates, and interlayer connection pads between corresponding conductive wires in two adjacent substrates, wherein the width of the interlayer connection pads is greater than the width of the conductive wires.

16. The co-fired ceramic substrate according to claim 14, characterized in that: The interlayer connection pads and the conductive wires are made of the same metal material.

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