Ceramic substrate and preparation method thereof, and chip packaging structure

Abstract

The invention discloses a ceramic substrate and a preparation method thereof, and a chip packaging structure, and belongs to the technical field of semiconductor packaging. According to the chip module, the grooves are formed between the mounting areas of the chip, and the flow blocking strips are arranged at the bottoms of the grooves along the grooves in an extending manner, so that the creepage distance between the upper conductive layers can be effectively increased by utilizing the grooves and the flow blocking strips, and the breakdown risk of the chip module when the tin overflow phenomenon occurs is reduced; the spacing limitation from the chip to the edge of the upper conductive layer is further shortened, so that the overall size of the ceramic substrate is reduced, and the trend that the semiconductor packaging module gradually develops towards miniaturization is met. The ceramic substrate provided by the embodiment of the invention effectively solves the problem that the size of an existing ceramic substrate cannot be further reduced due to a tin overflow phenomenon.

Description

Technical Field

[0001] This application belongs to the technical field of semiconductor packaging, and particularly relates to a ceramic substrate, a preparation method thereof, and a chip packaging structure. Background Art

[0002] With the gradual development of semiconductor packaging modules towards high power, integration, miniaturization, etc., the size of the copper-clad ceramic substrate used to carry chips, provide heat dissipation channels, and provide insulation protection is also becoming increasingly miniaturized.

[0003] Currently, chips and copper-clad ceramic substrates are mainly combined by high-temperature molten solder. However, solder paste has a certain fluidity at high temperatures. When the printing position of the solder paste is close to the edge of the upper copper layer, solder overflow is likely to occur. Solder overflow will lead to a reduction in the creepage distance between the upper copper layers, resulting in a risk of breakdown damage during product use.

[0004] In the prior art, to prevent solder overflow, usually a sufficient distance needs to be maintained between the printing position of the solder paste and the edge of the upper copper layer. Therefore, the size of the copper-clad ceramic substrate also needs to be increased accordingly, which goes against the trend of miniaturization development. Summary of the Invention

[0005] An object of the embodiments of this application is to provide a ceramic substrate, a preparation method thereof, and a chip packaging structure, which at least solve the problem that the existing ceramic substrate cannot be further reduced in size due to solder overflow.

[0006] In a first aspect, the embodiments of this application provide a ceramic substrate, which includes a substrate body and a first conductive layer. The front surface of the substrate body includes a plurality of mounting areas for mounting chips. The first conductive layer is disposed in the mounting areas. A groove is provided between adjacent mounting areas. The depth of the groove is less than the thickness of the substrate body, and a flow-blocking strip extending along the groove is provided at the bottom of the groove.

[0007] Optionally, in the ceramic substrate, the flow-blocking strip has a structure with a larger upper part and a smaller lower part; and / or the cross-section of the flow-blocking strip is in the shape of a king character, a dry character, an umbrella shape, a tree shape, or an antenna shape.

[0008] Optionally, in the ceramic substrate, a flow-blocking rib is further provided between the flow-blocking strip and the side wall of the groove.

[0009] Optionally, in the ceramic substrate, the flow-blocking rib is in the shape of a sawtooth or a wavy line.

[0010] Optionally, in the ceramic substrate, the width of the flow-blocking strip is less than the width of the groove.

[0011] Optionally, in the ceramic substrate, the height of the baffle strip is less than or equal to the depth of the groove.

[0012] Optionally, in the ceramic substrate, the width of the groove is 5 to 10 mm; and / or the width of the flow-blocking strip is 3 to 6 mm.

[0013] Optionally, in the ceramic substrate, the thickness of the substrate body is 0.5-1 mm; and / or the height of the flow-blocking strip is 0.3-0.6 mm.

[0014] Optionally, in the ceramic substrate, the material of the substrate body is at least one of aluminum oxide, aluminum nitride and silicon nitride.

[0015] Optionally, the ceramic substrate further includes a second conductive layer, and the second conductive layer is disposed on the back side of the substrate body.

[0016] Optionally, in the ceramic substrate, the first conductive layer and / or the second conductive layer is copper foil.

[0017] In a second aspect, an embodiment of the present application provides a method for preparing a ceramic substrate, the method comprising:

[0018] The ceramic powder, the photoinitiator, the dispersant and the plasticizer are ball-milled and mixed into a ceramic 3D printing slurry;

[0019] The ceramic 3D printing slurry is printed into a substrate blank by using a light-curing 3D printer, wherein the front side of the substrate blank has a mounting area, and a groove is adjacent to the mounting area, wherein the depth of the groove is less than the thickness of the substrate body, and a flow blocking strip extending along the groove is provided at the bottom of the groove;

[0020] calcining the substrate blank to obtain a substrate body;

[0021] A first conductive layer is formed in a mounting area on the front side of the substrate body.

[0022] Optionally, before calcining the substrate blank, the preparation method further comprises:

[0023] The substrate blank is subjected to a degreasing treatment.

[0024] Optionally, in the preparation method, at least one of aluminum oxide, aluminum nitride and silicon nitride;

[0025] The temperature of the degreasing treatment is 200-600°C, and the heating rate is 0.5-1.5°C / min; the temperature of the calcining treatment is 800-1750°C, and the heating rate is 2-10°C / min.

[0026] Optionally, in the preparation method, forming a first conductive layer in the mounting area on the front side of the substrate body includes:

[0027] The copper foil is bonded to the mounting area on the front side of the substrate body by using a direct copper bonding process.

[0028] In a third aspect, an embodiment of the present application provides a chip packaging structure, including the ceramic substrate as described above and a chip soldered on a first conductive layer in the ceramic substrate.

[0029] Compared with the prior art, this application has the following advantages:

[0030] In the embodiment of the present application, the ceramic substrate includes a substrate body and a first conductive layer, the front of the substrate body includes a plurality of mounting areas for mounting chips, the first conductive layer is arranged in the mounting areas, a groove is arranged between adjacent mounting areas, the depth of the groove is less than the thickness of the substrate body, and a blocking strip extending along the groove is arranged at the bottom of the groove. Among them, by arranging grooves between the mounting areas of the chip, and arranging blocking strips extending along the grooves at the bottom of the grooves, the creepage distance between the upper conductive layers can be effectively increased by using the grooves and the blocking strips, the breakdown risk of the chip module when the tin overflow phenomenon occurs is reduced, and the spacing limit from the chip to the edge of the upper conductive layer is further shortened, thereby reducing the overall size of the ceramic substrate, meeting the trend of semiconductor packaging modules gradually developing towards miniaturization. Therefore, the ceramic substrate provided in the embodiment of the present application effectively solves the problem that the existing ceramic substrate cannot be further reduced in size due to the tin overflow phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram showing a conventional chip packaging structure;

[0032] Figure 2 A schematic diagram showing the structure of a substrate body provided in an embodiment of the present application;

[0033] Figure 3 express Figure 2 A partial enlarged view of M in the middle;

[0034] Figure 4 express Figure 2 Another partial enlargement of the middle M;

[0035] Figure 5 A schematic diagram showing the structure of a ceramic substrate provided in an embodiment of the present application;

[0036] Figure 6 A flow chart showing a method for preparing a ceramic substrate provided in an embodiment of the present application;

[0037] Figure 7 A schematic diagram of a chip packaging structure provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0038] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] As semiconductor packaging modules gradually develop towards high power, integration, and miniaturization, the requirements for chip area and copper-clad ceramic substrate size are also gradually increasing. Among them, the main function of copper-clad ceramic substrates in semiconductor packaging modules is to carry chips, provide heat dissipation channels, and provide insulation protection. In order to match the miniaturization trend of semiconductor packaging devices, copper-clad ceramic substrates should minimize the area while ensuring the carrying of chips to meet the development trend of products.

[0042] At present, the chip and the copper-clad ceramic substrate are mainly combined together by high-temperature molten solder. This method requires first using a steel mesh to print solder paste on the upper copper layer of the copper-clad ceramic substrate, then placing the chip on the solder paste, and finally using a high-temperature reflow soldering process to combine the chip and the copper-clad ceramic substrate. However, since the solder paste has a certain fluidity at high temperatures, when the printing position of the solder paste is close to the edge of the upper copper layer, the solder paste is prone to overflow, such as Figure 1As shown in A in the figure, the tin overflow phenomenon will cause the creepage distance between the upper copper layers to decrease, such as Figure 1 As shown in B, there is a risk of breakdown damage during use of the product.

[0043] In order to prevent tin overflow, the solder paste printing position needs to be kept sufficiently away from the edge of the upper copper layer, such as Figure 1 As shown at C in the middle, this requires the size of the copper-clad ceramic substrate to be increased accordingly, which is contrary to the current trend of the packaging module gradually becoming smaller, that is, it cannot meet the development trend of the miniaturization of the module.

[0044] In view of the above problems, the present application provides a ceramic substrate 20, such as Figure 2 and Figure 5 As shown, the ceramic substrate 20 includes a substrate body 21 and a first conductive layer 22. The front side of the substrate body 21 includes a plurality of mounting areas 211 for mounting chips. The first conductive layer 22 is arranged in the mounting areas 211. A groove 23 is provided between adjacent mounting areas 211. The depth of the groove 23 is less than the thickness of the substrate body 21, and a blocking strip 24 extending along the groove 23 is provided at the bottom of the groove 23.

[0045] In the ceramic substrate 20 provided in the embodiment of the present application, the material of the substrate body 21 is ceramic, so that the substrate body 21 has excellent thermal conductivity and can effectively dissipate the heat generated by high-power devices; the material of the substrate body 21 is ceramic, which also makes the substrate body 21 have extremely high resistivity and breakdown voltage, can provide reliable electrical insulation, suitable for high voltage and high power applications, and prevent arcing and short circuits; the material of the substrate body 21 is ceramic, so that the substrate body 21 has high hardness and wear resistance, can withstand high temperature, mechanical stress and vibration, and is suitable for high reliability applications in harsh environments; in addition, the material of the substrate body 21 is ceramic, so that the thermal expansion coefficient of the substrate body 21 is low, and it can work stably in a high temperature environment; and the substrate body 21 has excellent corrosion resistance, suitable for application in harsh chemical environments such as acid, alkali and humid environments, and also has a low dielectric constant and loss factor, suitable for high-frequency circuits and radio frequency applications.

[0046] Optionally, the material of the substrate body 21 is at least one of aluminum oxide, aluminum nitride and silicon nitride, that is, it is made of one or more of aluminum oxide, aluminum nitride and silicon nitride, so that the substrate body 21 not only has high thermal conductivity, but also has excellent insulation performance, lower thermal expansion coefficient and dielectric constant and loss factor.

[0047] In the ceramic substrate 20 provided by the embodiment of the present application, the front surface of the substrate body 21 is divided into a plurality of mounting areas 211 by grooves 23, and a first conductive layer 22 is provided on each mounting area 211 to facilitate soldering with the chip; wherein, the depth of the groove 23 is less than the thickness of the substrate body 21, that is, the groove 23 does not penetrate the substrate body 21, which can ensure the overall structural strength of the substrate.

[0048] In the embodiment of the present application, the above-mentioned groove 23 is arranged around the periphery of the mounting area 211, so as to make each mounting area 211 independent of each other; the depth of the groove 23 is less than the thickness of the substrate body 21. Specifically, the remaining thickness of the substrate body 21 at the groove 23 is greater than or equal to 0.2 mm to ensure the overall structural strength of the substrate body 21. Optionally, in some embodiments, the thickness of the substrate body 21 is 0.5-1 mm, such as one of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm or a range value between any two of them; optionally, in some embodiments, the depth of the groove 23 is 0.3-0.6 mm, such as one of 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm or a range value between any two of them.

[0049] Optionally, the first conductive layer 22 is arranged on the mounting area 211 by means of paving, evaporation plating, bonding, etc., and the chip can be soldered on the first conductive layer 22, that is, the first conductive layer 22 and the chip are connected by solder. Among them, the first conductive layer 22 can be a copper layer structure such as copper foil, which is convenient for processing and manufacturing by means of evaporation plating, bonding, etc.

[0050] In the embodiment of the present application, the above-mentioned flow-blocking strip 24 is a convex structure on the bottom of the groove 23, which can effectively block the solder overflowing into the groove 23, increase the creepage distance between the two side conductive layers, and relieve the breakdown risk caused by the solder overflow phenomenon.

[0051] Among them, the above-mentioned flow-blocking strip 24 is a complex structure with folds or branches. On the premise of ensuring the structural strength, the longer the surface path is, the better the effect is. Optionally, the above-mentioned flow-blocking strip 24 has an upper-large-lower-small structure; optionally, in some embodiments, the cross-section of the above-mentioned flow-blocking strip 24 is in the shape of a king character, a dry character, an umbrella shape, a tree shape or an antenna shape, etc., which can increase the path length, thereby further improving the creepage distance between the two side conductive layers.

[0052] In the embodiment of the present application, by setting a groove 23 between the mounting areas 211 and extending a blocking strip 24 along the bottom of the groove 23, the groove 23 and the blocking strip 24 can be used to effectively increase the creepage distance between the upper conductive layers, thereby reducing the breakdown risk of the chip module when tin overflow occurs, further shortening the spacing limit from the chip to the edge of the upper conductive layer, and increasing the effective use area of ​​the upper copper layer, thereby reducing the overall size of the ceramic substrate 20, meeting the trend of semiconductor packaging modules gradually developing towards miniaturization. Therefore, the ceramic substrate 20 provided in the embodiment of the present application effectively solves the problem that the existing ceramic substrate 20 cannot be further reduced in size due to the tin overflow phenomenon.

[0053] For example, assuming that the chip size is 4mm and the solder is also set to 4mm, then under high temperature, the solder may expand to 5mm. Assuming that the upper copper layer is only 4.5mm, there will be 0.5mm of tin overflow, which means that the creepage distance between the upper copper layers is reduced, and there is a risk of breakdown. The existing technology is to increase the size of the upper copper layer to ensure that there is enough tin overflow distance from the edge of the chip to the edge of the copper layer; in the embodiment of the present application, a groove 23 is set between the copper layers, and a convex blocking strip 24 is set in the groove 23, which can effectively increase the creepage distance between the upper copper layers. Even if tin overflow occurs, Figure 7 As shown at D in the middle, the creepage distance between the copper layers is also sufficient to prevent breakdown, so there is no need to ensure sufficient tin overflow distance from the edge of the chip to the edge of the copper layer, thus shortening the spacing limit from the chip to the edge of the upper copper layer.

[0054] Optionally, in one embodiment, the width of the blocking strip 24 is smaller than the width of the groove 23 to ensure that the groove 23 can accommodate the overflow tin. Optionally, in a specific embodiment, the width of the groove 23 is 5 to 10 mm, for example, it can be one of 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or any range value between two; the width of the blocking strip 24 is 3 to 6 mm, for example, it can be one of 3 mm, 4 mm, 5 mm, 6 mm or any range value between two.

[0055] Optionally, in one embodiment, the height of the above-mentioned blocking strip 24 is less than or equal to the depth of the groove 23, which is convenient for processing and manufacturing, and also makes the blocking strip 24 not easily damaged or falling off under the protection of the groove 23. Optionally, in some specific embodiments, the height of the blocking strip 24 is 0.3-0.6 mm, for example, a range of one of 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, or any two thereof.

[0056] Optionally, in one embodiment, Figures 3-4As shown, a blocking convex pattern 25 is further provided between the blocking strip 24 and the side wall of the groove 23, which can further increase the creepage distance between adjacent first conductive layers 22. Optionally, in some embodiments, the blocking convex pattern 25 is in a sawtooth shape or a wavy line, wherein, to ensure structural strength, the height of a single tooth in the convex pattern is greater than or equal to 0.1 mm, and the spacing between teeth is greater than or equal to 0.05 mm.

[0057] Optionally, in one embodiment, the ceramic substrate 20 provided in the embodiment of the present application further includes a second conductive layer 26, which is disposed on the back of the substrate body 21, and the second conductive layer 26 is used to carry and weld electronic components on the back of the substrate body 21. Optionally, the second conductive layer is disposed on the back of the substrate body 21 by paving, evaporation, bonding, etc., and the electronic components can be soldered on the second conductive layer by solder. Among them, the second conductive layer can be a copper layer structure such as copper foil, which is convenient for processing and manufacturing by evaporation, bonding, etc., so that the ceramic substrate 20 provided in the embodiment of the present application is a double-sided copper-clad ceramic substrate 20.

[0058] See also Figure 6 , shows a flow chart of a method for preparing a ceramic substrate provided in an embodiment of the present application, the preparation method comprising steps 601 to 604.

[0059] Step 601: ball-mill ceramic powder, photoinitiator, dispersant and plasticizer to form ceramic 3D printing slurry.

[0060] In step 601, the ceramic powder may be one or more of aluminum oxide, aluminum nitride and silicon nitride; optionally, the ceramic powder may include 80 to 95 parts by mass of submicron ceramic powder and 3 to 10 parts by mass of nano-ceramic powder; wherein, considering that the smaller the powder particle size, the stronger the sintering performance, but the agglomeration ability will also be stronger; and the better the sintering performance, the easier it is for the material to be sintered densely, and the strength and toughness of the material will also be better, but the strong agglomeration ability will cause the additive to be unable to be evenly dispersed in the matrix; in the embodiment of the present application, the ceramic powder includes both submicron ceramic powder and nano-ceramic powder, and under the above-mentioned mass ratio, the submicron ceramic powder can have better sintering performance, while the nano-ceramic powder can help the matrix to sinter densely.

[0061] Optionally, in one embodiment, the particle size of the submicron ceramic powder may be 0.05-0.5 μm, and the particle size of the nano-scale ceramic powder may be 0.01-0.05 μm.

[0062] Optionally, in one embodiment, the ceramic powder further comprises La2O3 powder and SiC whisker powder, wherein La2O3 powder and SiC whisker powder added to the ceramic powder matrix can provide rod-shaped toughening, and the rod-shaped toughening can improve the toughness and bending strength of the alumina matrix.

[0063] Optionally, in a specific embodiment, the ceramic powder includes 80 to 95 parts of submicron Al2O3 powder, 3 to 10 parts of nano-Al2O3 powder, 1 to 5 parts of La2O3 powder, and 1 to 5 parts of SiC whisker powder by weight. Among them, La2O3 powder, SiC whisker powder and nano Al2O3 powder are all additives. La2O3 powder and SiC whisker powder can provide rod-like toughening when added to the alumina matrix, but will reduce the density of the alumina matrix. Rod-like toughening can improve the toughness and bending strength of the alumina matrix. A small amount of nano Al2O3 powder can help the alumina matrix to be sintered more easily and densely, and can also improve the toughness and bending strength of the alumina matrix. Under the above mass ratio, both the effect of rod-like toughening and the density of the alumina matrix are guaranteed, so as to prepare a high-strength and tough alumina substrate.

[0064] Optionally, the particle size of the La2O3 powder and SiC whisker powder can be 0.05-0.5 μm, and the comprehensive effect of the additives within this particle size range is better.

[0065] In the above step 601, the photosensitive resin, photoinitiator, dispersant and plasticizer can respectively adopt components known in the field of 3D printing; the ceramic powder, photosensitive resin, photoinitiator, dispersant and plasticizer are added to the ball milling medium for ball milling mixing. The ball milling speed and time are preferably 300-350r / min and 6-8h respectively, so as to ball mill into a ceramic slurry suitable for photocuring 3D printing.

[0066] Step 602: Use a light-curing 3D printer to print the ceramic 3D printing slurry into a substrate blank, wherein the front side of the substrate blank has a mounting area, and a groove adjacent to the mounting area, wherein the depth of the groove is less than the thickness of the substrate body, and a flow blocking strip extending along the groove is provided at the bottom of the groove.

[0067] In step 602, the ceramic 3D printing slurry is placed in the material tank of the light-curing 3D printer; then based on the design requirements that the front side has a mounting area, the adjacent mounting area has a groove, the depth of the groove is less than the thickness of the substrate body, and the bottom of the groove is provided with a flow barrier extending along the groove, the ceramic substrate is first modeled and sliced ​​by computer software, and then the substrate blank is manufactured by layered exposure and layer-by-layer stacking.

[0068] Step 603: calcining the substrate blank to obtain a substrate body.

[0069] In step 603, the substrate blank is placed in a protective gas atmosphere sintering furnace for sintering to obtain a substrate body.

[0070] Step 604: forming a first conductive layer in the mounting area on the front side of the substrate body.

[0071] In step 604, a metal layer is formed on the mounting area on the front side of the substrate body by paving, evaporation, bonding, etc., which can serve as the above-mentioned first conductive layer.

[0072] The control method provided in the embodiment of the present application, after ball-milling and mixing ceramic powder, photoinitiator, dispersant and plasticizer into ceramic 3D printing slurry, uses 3D printing to produce a substrate blank having a mounting area on the front side, a groove in the adjacent mounting area, the depth of the groove is less than the thickness of the substrate body, and a baffle extending along the groove is provided at the bottom of the groove, and then a first conductive layer is formed in the mounting area on the front side by calcination, so that the prepared ceramic substrate can effectively increase the creepage distance between the upper conductive layers by using the groove and the baffle, reduce the breakdown risk of the chip module when tin overflow occurs, further shorten the spacing limit from the chip to the edge of the upper conductive layer, thereby reducing the overall size of the ceramic substrate, and meeting the trend of semiconductor packaging modules gradually developing towards miniaturization. Therefore, the ceramic substrate provided in the embodiment of the present application effectively solves the problem that the existing ceramic substrate cannot be further reduced in size due to the tin overflow phenomenon.

[0073] Optionally, in one embodiment, at least one of aluminum oxide, aluminum nitride and silicon nitride makes the substrate body not only have high thermal conductivity, but also have excellent insulation performance, lower thermal expansion coefficient and dielectric constant and loss factor.

[0074] Optionally, in a specific embodiment, when the ceramic powder includes 80 to 95 parts of submicron Al2O3 powder, 3 to 10 parts of nano-Al2O3 powder, 1 to 5 parts of La2O3 powder, and 1 to 5 parts of SiC whisker powder by mass, the calcination temperature is 800 to 1750°C and the heating rate is 2 to 10°C / min, which can effectively take into account the sintering efficiency and reduce surface cracks, and ensure the structural strength of the substrate body. Optionally, the calcination process is: in a nitrogen atmosphere, the temperature is increased to 800 to 1200°C at a rate of 5 to 10°C / min; then the temperature is increased to 1600 to 1750°C at a rate of 2 to 5°C / min, and the temperature is kept for 2 to 4 hours; then the temperature is reduced to 800 to 1200°C at a rate of 2 to 10°C / min; finally, the Al2O3-based ceramic substrate is obtained by cooling to room temperature with the furnace.

[0075] Optionally, in one embodiment, before calcining the substrate blank, the method further comprises:

[0076] The substrate blank is subjected to a degreasing treatment.

[0077] In this embodiment, the ceramic substrate blank is placed in a vacuum degreasing furnace or other equipment for degreasing treatment before calcination, which can volatilize the photosensitive resin, photoinitiator, dispersant and plasticizer in the ceramic blank, thereby improving product quality.

[0078] Optionally, in a specific embodiment, when the above-mentioned ceramic powder includes 80 to 95 parts of submicron Al2O3 powder, 3 to 10 parts of nanometer Al2O3 powder, 1 to 5 parts of La2O3 powder, and 1 to 5 parts of SiC whisker powder, by mass, the degreasing treatment temperature is 200 to 600°C, and the heating rate is 0.5 to 1.5°C / min, which can effectively take into account the degreasing efficiency and reduce surface cracks, thereby ensuring the structural strength of the substrate body. Optionally, the degreasing process is: in a nitrogen atmosphere, heating to 200-220°C at a rate of 0.5-1.5°C / min, and keeping warm for 0.5-3h; then heating to 320-380°C at a rate of 0.5-1.5°C / min, and keeping warm for 0.5-3h; then heating to 550-600°C at a rate of 0.5-1.5°C / min, and keeping warm for 0.5-2h; finally cooling to room temperature with the furnace to obtain a degreased Al2O3-based ceramic substrate blank.

[0079] Optionally, in a specific implementation manner, the preparation method provided in the embodiment of the present application forms a first conductive layer in the mounting area on the front side of the substrate body, comprising:

[0080] The copper foil is bonded to the mounting area on the front side of the substrate body by using a direct copper bonding process.

[0081] In this specific implementation, a direct copper bonding (DCB) process is used to bond the substrate body and the copper foil together to produce a high-strength and tough front copper-clad ceramic substrate.

[0082] In this specific embodiment, in the direct copper bonding process, the temperature is 1000-1100° C., the pressure is 20-40 MPa), and the processing time is 10-30 min, so that the copper foil can be bonded to the front side of the ceramic substrate.

[0083] Optionally, in one embodiment, the preparation method provided in the examples of the present application further comprises:

[0084] A second conductive layer is formed on the back side of the substrate body.

[0085] In this embodiment, a metal layer is formed on the mounting area on the front side of the substrate body by paving, evaporation, bonding, etc., which can serve as the above-mentioned second conductive layer, and the second conductive layer is used to carry and weld electronic components on the back side of the substrate body.

[0086] Optionally, in a specific implementation manner, forming a second conductive layer on the back side of the substrate body includes:

[0087] The copper foil is bonded to the back side of the substrate body by using a direct copper bonding process.

[0088] In this specific embodiment, a direct copper bonding (DCB) process is used to bond the substrate body and the copper foil together to produce a high-strength and tough double-sided copper-clad ceramic substrate.

[0089] In this specific embodiment, in the direct copper bonding process, the temperature is 1000-1100° C., the pressure is 20-40 MPa), and the processing time is 10-30 min, so that the copper foil can be bonded to the back side of the ceramic substrate.

[0090] The present application embodiment also provides a chip packaging structure 100, such as Figure 7 As shown, it includes the ceramic substrate 20 as described above and a chip 30 soldered on the first conductive layer in the ceramic substrate 10. The chip 30 can be soldered on the first conductive layer 22 on the front side of the ceramic substrate 20 through the solder layer 31.

[0091] For the above chip packaging structure embodiment, it includes the above ceramic substrate and can achieve the same technical effect. In order to avoid repetition, it will not be described here. For related matters, please refer to the partial description of the ceramic substrate embodiment.

[0092] The chip packaging structure provided in the embodiment of the present application has grooves arranged between the mounting areas of the ceramic substrate, and blocking strips are arranged at the bottom of the grooves and extending along the grooves. The grooves and blocking strips can be used to effectively increase the creepage distance between the upper conductive layers, thereby reducing the breakdown risk of the chip module when tin overflow occurs, and further shortening the spacing limit from the chip to the edge of the upper conductive layer, thereby reducing the overall size of the ceramic substrate and meeting the trend of semiconductor packaging modules gradually developing towards miniaturization. Therefore, the ceramic substrate provided in the embodiment of the present application effectively solves the problem that the existing ceramic substrate cannot be further reduced in size due to the tin overflow phenomenon.

[0093] In order to make the invention purpose, technical solution and beneficial effects of the present application clearer, the present application is further described below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present application and are not used to limit the scope of the present application.

[0094] The present application is described in detail below through examples.

[0095] Example 1

[0096] (1) Weigh 90 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano-Al2O3 powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as ball-milling media and anhydrous ethanol as a solvent for mixing and ball-milling. The ball-milling speed and time are 350 r / min and 6 h respectively. After drying, Al2O3-based ceramic powder is obtained.

[0097] (2) Weigh a certain amount of Al2O3-based ceramic powder, photosensitive resin, photoinitiator, dispersant, and plasticizer. Add ball-milling media for ball-milling and mixing. The ball-milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain Al2O3-based ceramic 3D printing slurry.

[0098] (3) Place the Al2O3-based ceramic 3D printing slurry in the material tank of a light-curing 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 1 mm, the depth of the groove is 0.6 mm, the width is 10 mm, and a flow-blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow-blocking strip is 0.6 mm, the width is 5 mm, the flow-blocking strip has a structure with a larger upper part and a smaller lower part, and the cross-section of the flow-blocking strip is in the shape of the Chinese character '王' (wang). First, complete the modeling and slicing of the ceramic substrate by computer software, and then manufacture the Al2O3-based ceramic substrate blank through layer-by-layer exposure and stacking.

[0099] (4) Place the obtained Al2O3-based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: In a nitrogen atmosphere, heat up to 200 °C at a rate of 0.5 °C / min and hold for 2 h; then heat up to 350 °C at a rate of 0.5 °C / min and hold for 2 h; heat up to 550 °C at a rate of 0.5 °C / min and hold for 1 h; finally, cool down to room temperature with the furnace.

[0100] (5) Place the debound Al2O3-based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: In a nitrogen atmosphere, heat up to 800 °C at a rate of 10 °C / min; then heat up to 1700 °C at a rate of 5 °C / min and hold for 2 h; subsequently, cool down to 800 °C at a rate of 10 °C / min; finally, cool down to room temperature with the furnace to obtain the Al2O3-based ceramic substrate.

[0101] (6) Bond the front mounting area of the Al2O3 ceramic substrate with copper foil using the DCB process to finally obtain a high-strength and tough single-sided copper-clad alumina ceramic substrate.

[0102] Example 2

[0103] (1) Weigh 80 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 10 parts by mass of nano - Al2O3 powder with a particle size of 0.01 - 0.05 μm, 5 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 5 parts by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as the ball - milling medium and anhydrous ethanol as the solvent for ball - milling. The ball - milling speed and time are 350 r / min and 6 h respectively. After drying, an Al2O3 - based ceramic powder is obtained.

[0104] (2) Weigh a certain amount of Al2O3 - based ceramic powder, photosensitive resin, photo - initiator, dispersant, and plasticizer. Add the ball - milling medium for ball - milling and mixing. The ball - milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain an Al2O3 - based ceramic 3D printing slurry.

[0105] (3) Place the Al2O3 - based ceramic 3D printing slurry in the material tank of a light - curing 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 1 mm, the depth of the groove is 0.6 mm, the width is 10 mm, and a flow - blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow - blocking strip is 0.6 mm, the width is 5 mm, the flow - blocking strip has an upper - large - lower - small structure, and the cross - section of the flow - blocking strip is in the shape of a Chinese character 'Wang'. First, the computer software completes the modeling and slicing of the ceramic substrate, and then an Al2O3 - based ceramic substrate blank is manufactured by means of layer - by - layer exposure and stacking.

[0106] (4) Place the obtained Al2O3 - based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: in a nitrogen atmosphere, heat up to 200 °C at a rate of 0.5 °C / min and hold for 2 h; then heat up to 350 °C at a rate of 0.5 °C / min and hold for 2 h; heat up to 550 °C at a rate of 0.5 °C / min and hold for 1 h; finally, cool down to room temperature with the furnace.

[0107] (5) Place the debound Al2O3 - based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: in a nitrogen atmosphere, heat up to 800 °C at a rate of 10 °C / min; then heat up to 1700 °C at a rate of 5 °C / min and hold for 2 h; subsequently, cool down to 800 °C at a rate of 10 °C / min; finally, cool down to room temperature with the furnace to obtain an Al2O3 - based ceramic substrate.

[0108] (6) Adopt the DCB process to bond the front mounting area of the Al2O3 ceramic substrate with copper foil, and finally obtain a high - strength and tough single - sided copper - clad alumina ceramic substrate.

[0109] Example 3

[0110] (1) Weigh 95 parts by weight of Al2O3 powder with a particle size of 0.1 to 0.5 μm, 3 parts by weight of nano-Al2O3 powder with a particle size of 0.01 to 0.05 μm, 1 part by weight of La2O3 powder with a particle size of 0.01 to 0.05 μm, and 1 part by weight of SiC whisker powder with a particle size of 0.01 to 0.05 μm, add alumina balls as a ball milling medium and anhydrous ethanol as a solvent, mix and ball mill, the ball milling speed and time are 350 r / min and 6 h respectively, and then dry to obtain Al2O3-based ceramic powder;

[0111] (2) Weigh a certain amount of Al2O3-based ceramic powder, photosensitive resin, photoinitiator, dispersant and plasticizer, add ball milling medium for ball milling, and the ball milling speed and time are preferably 300-350 r / min and 6-8 h, respectively, to obtain Al2O3-based ceramic 3D printing slurry;

[0112] (3) placing Al2O3-based ceramic 3D printing slurry in the material tank of a light-curing 3D printer, based on the front side having a mounting area, the adjacent mounting area having a groove, the thickness of the substrate body being 1 mm, the depth of the groove being 0.6 mm, the width being 10 mm, and the bottom of the groove being provided with a flow blocker extending along the groove, the flow blocker having a height of 0.6 mm and a width of 5 mm, the flow blocker having a structure of being larger at the top and smaller at the bottom, and the cross section of the flow blocker having a dry-shaped design requirement, firstly completing the modeling and slicing of the ceramic substrate by computer software, and then manufacturing the Al2O3-based ceramic substrate blank by layered exposure and layer-by-layer stacking;

[0113] (4) The obtained Al2O3-based ceramic substrate blank is placed in a vacuum degreasing furnace for degreasing treatment. The degreasing process is as follows: in a nitrogen atmosphere, the temperature is raised to 200°C at a rate of 0.5°C / min and kept at this temperature for 2 hours; then the temperature is raised to 350°C at a rate of 0.5°C / min and kept at this temperature for 2 hours; the temperature is raised to 550°C at a rate of 0.5°C / min and kept at this temperature for 1 hour; and finally the temperature is cooled to room temperature along with the furnace;

[0114] (5) placing the degreased Al2O3-based ceramic substrate blank in an atmosphere sintering furnace, and the sintering process is as follows: in a nitrogen atmosphere, heating to 800°C at a rate of 10°C / min; then heating to 1700°C at a rate of 5°C / min, and keeping the temperature for 2h; then cooling to 800°C at a rate of 10°C / min; and finally cooling to room temperature with the furnace to obtain an Al2O3-based ceramic substrate;

[0115] (6) The front mounting area of ​​the Al2O3 ceramic substrate is bonded to the copper foil using the DCB process, and finally a high-strength and tough single-sided copper-clad alumina ceramic substrate is produced.

[0116] Example 4

[0117] (1) Weigh 90 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano - Al2O3 powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as the ball - milling medium and anhydrous ethanol as the solvent for mixing and ball - milling. The ball - milling speed and time are 350 r / min and 6 h respectively. After drying, Al2O3 - based ceramic powder is obtained.

[0118] (2) Weigh a certain amount of Al2O3 - based ceramic powder, photosensitive resin, photo - initiator, dispersant, and plasticizer. Add the ball - milling medium for ball - milling and mixing. The ball - milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain Al2O3 - based ceramic 3D printing slurry.

[0119] (3) Place the Al2O3 - based ceramic 3D printing slurry in the material tank of a photocuring 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 1 mm, the depth of the groove is 0.6 mm, the width is 10 mm, and a flow - blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow - blocking strip is 0.6 mm, the width is 5 mm, the flow - blocking strip has a structure with a larger upper part and a smaller lower part, and the cross - section of the flow - blocking strip is in the shape of the Chinese character 'Wang'. First, the computer software completes the modeling and slicing of the ceramic substrate, and then the Al2O3 - based ceramic substrate blank is manufactured by means of layer - by - layer exposure and stacking.

[0120] (4) Place the obtained Al2O3 - based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: in a nitrogen atmosphere, heat up to 220 °C at a rate of 1.5 °C / min and hold for 3 h; then heat up to 380 °C at a rate of 1.5 °C / min and hold for 3 h; heat up to 600 °C at a rate of 1.5 °C / min and hold for 2 h; finally, cool down to room temperature with the furnace.

[0121] (5) Place the debound Al2O3 - based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: in a nitrogen atmosphere, heat up to 1200 °C at a rate of 10 °C / min; then heat up to 1750 °C at a rate of 5 °C / min and hold for 4 h; subsequently, cool down to 1200 °C at a rate of 10 °C / min; finally, cool down to room temperature with the furnace to obtain the Al2O3 - based ceramic substrate.

[0122] (6) Adopt the DCB process to bond the front mounting area of the Al2O3 ceramic substrate with copper foil, and finally obtain a high - strength and tough single - sided copper - clad alumina ceramic substrate.

[0123] Example 5

[0124] (1) Weigh 90 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano-Al2O3 powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as the ball-milling medium and anhydrous ethanol as the solvent for mixing and ball-milling. The ball-milling speed and time are 350 r / min and 6 h respectively. After drying, Al2O3-based ceramic powder is obtained.

[0125] (2) Weigh a certain amount of Al2O3-based ceramic powder, photosensitive resin, photoinitiator, dispersant, and plasticizer. Add the ball-milling medium for ball-milling and mixing. The ball-milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain Al2O3-based ceramic 3D printing slurry.

[0126] (3) Place the Al2O3-based ceramic 3D printing slurry in the material tank of a photocuring 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 1 mm, the depth of the groove is 0.6 mm, the width is 10 mm, and a flow-blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow-blocking strip is 0.6 mm, the width is 5 mm, the flow-blocking strip has a structure with a larger upper part and a smaller lower part, and the cross-section of the flow-blocking strip is in the shape of the Chinese character 'Wang'. First, the computer software completes the modeling and slicing of the ceramic substrate, and then the Al2O3-based ceramic substrate blank is manufactured by means of layer-by-layer exposure and stacking.

[0127] (4) Place the obtained Al2O3-based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: In a nitrogen atmosphere, heat it to 210 °C at a rate of 1.0 °C / min and hold for 0.5 h; then heat it to 320 °C at a rate of 1.0 °C / min and hold for 0.5 h; heat it to 600 °C at a rate of 1.0 °C / min and hold for 0.5 h; finally, cool it to room temperature with the furnace.

[0128] (5) Place the debound Al2O3-based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: In a nitrogen atmosphere, heat it to 1000 °C at a rate of 7.5 °C / min; then heat it to 1600 °C at a rate of 2 °C / min and hold for 3 h; subsequently, cool it to 1000 °C at a rate of 6 °C / min; finally, cool it to room temperature with the furnace to obtain the Al2O3-based ceramic substrate.

[0129] (6) Adopt the DCB process to bond the front mounting area of the Al2O3 ceramic substrate with the copper foil, and finally obtain a high-strength and tough single-sided copper-clad alumina ceramic substrate.

[0130] Example 6

[0131] (1), Weigh 90 parts by mass of silicon nitride powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano - silicon nitride powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as ball - milling media and anhydrous ethanol as a solvent for ball - milling. The ball - milling speed and time are 350 r / min and 6 h respectively. After drying, an Al2O3 - based ceramic powder is obtained;

[0132] (2), Weigh a certain amount of silicon nitride - based ceramic powder, photosensitive resin, photo - initiator, dispersant, and plasticizer. Add ball - milling media for ball - milling and mixing. The ball - milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain a silicon nitride - based ceramic 3D printing slurry;

[0133] (3), Place the silicon nitride - based ceramic 3D printing slurry in the material tank of a photocuring 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 1 mm, the depth of the groove is 0.6 mm, the width is 10 mm, and a flow - blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow - blocking strip is 0.6 mm, the width is 5 mm, the flow - blocking strip has a structure with a larger upper part and a smaller lower part, and the cross - section of the flow - blocking strip is in the shape of the Chinese character 'Wang'. First, the computer software completes the modeling and slicing of the ceramic substrate, and then the silicon nitride - based ceramic substrate blank is manufactured by means of layer - by - layer exposure and stacking;

[0134] (4), Place the obtained silicon nitride - based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: In a nitrogen atmosphere, heat it at a rate of 0.5 °C / min to 200 °C and hold for 2 h; then heat it at a rate of 0.5 °C / min to 350 °C and hold for 2 h; heat it at a rate of 0.5 °C / min to 550 °C and hold for 1 h; finally, cool it to room temperature with the furnace;

[0135] (5), Place the debound silicon nitride - based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: In a nitrogen atmosphere, heat it at a rate of 10 °C / min to 800 °C; then heat it at a rate of 5 °C / min to 1700 °C and hold for 2 h; subsequently, cool it at a rate of 10 °C / min to 800 °C; finally, cool it to room temperature with the furnace to obtain a silicon nitride - based ceramic substrate;

[0136] (6), Adopt the DCB process to bond the front mounting area of the silicon nitride ceramic substrate with copper foil, and finally obtain a high - strength and tough single - sided copper - clad silicon nitride ceramic substrate.

[0137] Example 7

[0138] (1) Weigh 90 parts by weight of Al2O3 powder with a particle size of 0.1 to 0.5 μm, 5 parts by weight of nano-Al2O3 powder with a particle size of 0.01 to 0.05 μm, 4 parts by weight of La2O3 powder with a particle size of 0.01 to 0.05 μm, and 1 part by weight of SiC whisker powder with a particle size of 0.01 to 0.05 μm, add alumina balls as a ball milling medium and anhydrous ethanol as a solvent, mix and ball mill, the ball milling speed and time are 350 r / min and 6 h respectively, and then dry to obtain Al2O3-based ceramic powder;

[0139] (2) Weigh a certain amount of Al2O3-based ceramic powder, photosensitive resin, photoinitiator, dispersant and plasticizer, add ball milling medium for ball milling, and the ball milling speed and time are preferably 300-350 r / min and 6-8 h, respectively, to obtain Al2O3-based ceramic 3D printing slurry;

[0140] (3) placing Al2O3-based ceramic 3D printing slurry in the material tank of a light-curing 3D printer, based on the front side having a mounting area, the adjacent mounting area having a groove, the thickness of the substrate body being 1 mm, the depth of the groove being 0.6 mm, the width being 10 mm, and the bottom of the groove being provided with a flow blocker extending along the groove, the flow blocker having a height of 0.6 mm and a width of 5 mm, the flow blocker having a structure of being larger at the top and smaller at the bottom, and the cross section of the flow blocker having a dry-shaped design requirement, firstly completing the modeling and slicing of the ceramic substrate by computer software, and then manufacturing the Al2O3-based ceramic substrate blank by layered exposure and layer-by-layer stacking;

[0141] (4) The obtained Al2O3-based ceramic substrate blank is placed in a vacuum degreasing furnace for degreasing treatment. The degreasing process is as follows: in a nitrogen atmosphere, the temperature is raised to 200°C at a rate of 0.5°C / min and kept at this temperature for 2 hours; then the temperature is raised to 350°C at a rate of 0.5°C / min and kept at this temperature for 2 hours; the temperature is raised to 550°C at a rate of 0.5°C / min and kept at this temperature for 1 hour; and finally the temperature is cooled to room temperature along with the furnace;

[0142] (5) placing the degreased Al2O3-based ceramic substrate blank in an atmosphere sintering furnace, and the sintering process is as follows: in a nitrogen atmosphere, heating to 800°C at a rate of 10°C / min; then heating to 1700°C at a rate of 5°C / min, and keeping the temperature for 2h; then cooling to 800°C at a rate of 10°C / min; and finally cooling to room temperature with the furnace to obtain an Al2O3-based ceramic substrate;

[0143] (6) The front mounting area of ​​the silicon nitride ceramic substrate is bonded to the copper foil using the DCB process, and finally a high-strength and tough single-sided copper-clad silicon nitride ceramic substrate is produced.

[0144] Example 8

[0145] (1) Weigh 90 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano - Al2O3 powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as ball - milling media and anhydrous ethanol as a solvent for ball - milling. The ball - milling speed and time are 350 r / min and 6 h respectively. Then, dry it to obtain Al2O3 - based ceramic powder.

[0146] (2) Weigh a certain amount of Al2O3 - based ceramic powder, photosensitive resin, photo - initiator, dispersant, and plasticizer. Add ball - milling media for ball - milling and mixing. The ball - milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain Al2O3 - based ceramic 3D printing slurry.

[0147] (3) Place the Al2O3 - based ceramic 3D printing slurry in the material tank of a photocuring 3D printer. Based on the design requirements that the front side has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 1 mm, the depth of the groove is 0.6 mm, the width is 10 mm, and a flow - blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow - blocking strip is 0.6 mm, the width is 5 mm, the flow - blocking strip has a structure with a larger upper part and a smaller lower part, the cross - section of the flow - blocking strip is in the shape of the Chinese character 'Wang', and there are serrated flow - blocking ridges with a height of 0.1 mm and a tooth pitch of 0.05 mm between the flow - blocking strip and the side wall of the groove. First, complete the modeling and slicing of the ceramic substrate by computer software, and then manufacture the Al2O3 - based ceramic substrate blank through layer - by - layer exposure and stacking.

[0148] (4) Place the obtained Al2O3 - based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: In a nitrogen atmosphere, heat it at a rate of 0.5 °C / min to 200 °C and hold for 2 h; then heat it at a rate of 0.5 °C / min to 350 °C and hold for 2 h; heat it at a rate of 0.5 °C / min to 550 °C and hold for 1 h; finally, cool it to room temperature with the furnace.

[0149] (5) Place the debound Al2O3 - based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: In a nitrogen atmosphere, heat it at a rate of 10 °C / min to 800 °C; then heat it at a rate of 5 °C / min to 1700 °C and hold for 2 h; subsequently, cool it to 800 °C at a rate of 10 °C / min; finally, cool it to room temperature with the furnace to obtain the Al2O3 - based ceramic substrate.

[0150] (6) Adopt the DCB process to bond the front mounting area of the Al2O3 ceramic substrate with copper foil, and finally obtain a high - strength and high - toughness single - sided copper - clad alumina ceramic substrate.

[0151] Example 9

[0152] (1) Weigh 90 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano - Al2O3 powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as the ball - milling medium and anhydrous ethanol as the solvent for ball - milling. The ball - milling speed and time are 350 r / min and 6 h respectively. After drying, Al2O3 - based ceramic powder is obtained.

[0153] (2) Weigh a certain amount of Al2O3 - based ceramic powder, photosensitive resin, photo - initiator, dispersant, and plasticizer. Add the ball - milling medium for ball - milling and mixing. The ball - milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain Al2O3 - based ceramic 3D printing slurry.

[0154] (3) Place the Al2O3 - based ceramic 3D printing slurry in the material tank of a stereolithography 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 0.5 mm, the depth of the groove is 0.3 mm, the width is 5 mm, and a flow - blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow - blocking strip is 0.3 mm, the width is 3 mm, the flow - blocking strip has a structure with a larger upper part and a smaller lower part, and the cross - section of the flow - blocking strip is in the shape of the Chinese character 'Wang'. First, the computer software completes the modeling and slicing of the ceramic substrate, and then the Al2O3 - based ceramic substrate blank is manufactured by means of layer - by - layer exposure and stacking.

[0155] (4) Place the obtained Al2O3 - based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: in a nitrogen atmosphere, heat up to 200 °C at a rate of 0.5 °C / min and hold for 2 h; then heat up to 350 °C at a rate of 0.5 °C / min and hold for 2 h; heat up to 550 °C at a rate of 0.5 °C / min and hold for 1 h; finally, cool down to room temperature with the furnace.

[0156] (5) Place the debound Al2O3 - based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: in a nitrogen atmosphere, heat up to 800 °C at a rate of 10 °C / min; then heat up to 1700 °C at a rate of 5 °C / min and hold for 2 h; subsequently, cool down to 800 °C at a rate of 10 °C / min; finally, cool down to room temperature with the furnace to obtain the Al2O3 - based ceramic substrate.

[0157] (6) Adopt the DCB process to bond the front mounting area of the Al2O3 ceramic substrate with copper foil, and finally obtain a high - strength and tough single - sided copper - clad alumina ceramic substrate.

[0158] Example 10

[0159] (1) Weigh 90 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano - Al2O3 powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as the ball - milling medium and anhydrous ethanol as the solvent for ball - milling. The ball - milling speed and time are 350 r / min and 6 h respectively. After drying, Al2O3 - based ceramic powder is obtained.

[0160] (2) Weigh a certain amount of Al2O3 - based ceramic powder, photosensitive resin, photo - initiator, dispersant, and plasticizer. Add the ball - milling medium for ball - milling and mixing. The ball - milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain Al2O3 - based ceramic 3D printing slurry.

[0161] (3) Place the Al2O3 - based ceramic 3D printing slurry in the material tank of a light - curing 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 0.8 mm, the depth of the groove is 0.4 mm, the width is 8 mm, and a flow - blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow - blocking strip is 0.4 mm, the width is 5 mm, the flow - blocking strip has a structure with a larger upper part and a smaller lower part, and the cross - section of the flow - blocking strip is in the shape of a Chinese character 'Wang'. First, the computer software completes the modeling and slicing of the ceramic substrate, and then the Al2O3 - based ceramic substrate blank is manufactured by means of layer - by - layer exposure and stacking.

[0162] (4) Place the obtained Al2O3 - based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: In a nitrogen atmosphere, heat up to 200 °C at a rate of 0.5 °C / min and hold for 2 h; then heat up to 350 °C at a rate of 0.5 °C / min and hold for 2 h; heat up to 550 °C at a rate of 0.5 °C / min and hold for 1 h; finally, cool down to room temperature with the furnace.

[0163] (5) Place the debound Al2O3 - based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: In a nitrogen atmosphere, heat up to 800 °C at a rate of 10 °C / min; then heat up to 1700 °C at a rate of 5 °C / min and hold for 2 h; subsequently, cool down to 800 °C at a rate of 10 °C / min; finally, cool down to room temperature with the furnace to obtain the Al2O3 - based ceramic substrate.

[0164] (6) Adopt the DCB process to bond the front mounting area of the Al2O3 ceramic substrate with copper foil, and finally obtain a high - strength and tough single - sided copper - clad alumina ceramic substrate.

[0165] Example 11

[0166] (1) Weigh 90 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 5 parts by mass of nano - Al2O3 powder with a particle size of 0.01 - 0.05 μm, 4 parts by mass of La2O3 powder with a particle size of 0.01 - 0.05 μm, and 1 part by mass of SiC whisker powder with a particle size of 0.01 - 0.05 μm. Add alumina balls as ball - milling media and anhydrous ethanol as a solvent for ball - milling. The ball - milling speed and time are 350 r / min and 6 h respectively, and then dry to obtain Al2O3 - based ceramic powder.

[0167] (2) Weigh a certain amount of Al2O3 - based ceramic powder, photosensitive resin, photo - initiator, dispersant, and plasticizer, add ball - milling media for ball - milling and mixing. The ball - milling speed and time are preferably 300 - 350 r / min and 6 - 8 h respectively to obtain Al2O3 - based ceramic 3D printing slurry.

[0168] (3) Place the Al2O3 - based ceramic 3D printing slurry in the material tank of a light - curing 3D printer. Based on the design requirements that the front has a mounting area, adjacent mounting areas have grooves, the thickness of the substrate body is 1 mm, the depth of the groove is 0.6 mm, the width is 10 mm, and a flow - blocking strip extending along the groove is provided at the bottom of the groove. The height of the flow - blocking strip is 0.6 mm, the width is 5 mm, the flow - blocking strip has a structure that is larger at the top and smaller at the bottom, and the cross - section of the flow - blocking strip is in the shape of a Chinese character 'Wang'. First, complete the modeling and slicing of the ceramic substrate by computer software, and then manufacture the Al2O3 - based ceramic substrate blank by layer - by - layer exposure and stacking.

[0169] (4) Place the obtained Al2O3 - based ceramic substrate blank in a vacuum debinding furnace for debinding treatment. The debinding process is as follows: in a nitrogen atmosphere, heat up to 200 °C at a rate of 0.5 °C / min and hold for 2 h; then heat up to 350 °C at a rate of 0.5 °C / min and hold for 2 h; heat up to 550 °C at a rate of 0.5 °C / min and hold for 1 h; finally, cool to room temperature with the furnace.

[0170] (5) Place the debound Al2O3 - based ceramic substrate blank in an atmosphere sintering furnace. The sintering process is as follows: in a nitrogen atmosphere, heat up to 800 °C at a rate of 10 °C / min; then heat up to 1700 °C at a rate of 5 °C / min and hold for 2 h; subsequently, cool to 800 °C at a rate of 10 °C / min; finally, cool to room temperature with the furnace to obtain the Al2O3 - based ceramic substrate.

[0171] (6) Adopt the DCB process to bond the front mounting area and the back of the Al2O3 ceramic substrate with copper foil respectively, and finally obtain a high - strength and high - toughness double - sided copper - clad alumina ceramic substrate.

[0172] Tests have shown that, compared with existing ceramic substrates without grooves and blocking strips, the ceramic substrates prepared in Examples 1 to 11 can significantly increase the creepage distance between the upper conductive layers, effectively reducing the breakdown risk of the chip soldered on the conductive layer when tin overflow occurs.

[0173] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present application.

[0174] The above is a detailed introduction to a ceramic substrate and its preparation method, as well as a chip packaging structure provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A ceramic substrate, characterized in that: The ceramic substrate includes a substrate body and a first conductive layer. The front surface of the substrate body includes a plurality of mounting areas for mounting chips. The first conductive layer is disposed in the mounting areas. Grooves are provided between adjacent mounting areas. The depth of the grooves is less than the thickness of the substrate body, and a flow-blocking strip extending along the grooves is provided at the bottom of the grooves.

2. The ceramic substrate according to claim 1, characterized in that: The flow-blocking strip has a structure with a larger upper part and a smaller lower part; and / or the cross-section of the flow-blocking strip is in the shape of a Chinese character 'wang', 'gan', 'umbrella', 'tree' or 'antenna'.

3. The ceramic substrate according to claim 1, characterized in that: A flow-blocking rib is further provided between the flow-blocking strip and the side wall of the groove.

4. The ceramic substrate according to claim 3, characterized in that: The flow-blocking rib is in a zigzag or wavy line shape.

5. The ceramic substrate according to claim 1, characterized in that: The width of the flow-blocking strip is less than the width of the groove; and / or the height of the flow-blocking strip is less than or equal to the depth of the groove.

6. The ceramic substrate according to claim 1, characterized in that: The width of the groove is 5 - 10 mm; and / or the width of the flow-blocking strip is 3 - 6 mm.

7. The ceramic substrate according to claim 1, characterized in that: The thickness of the substrate body is 0.5 - 1 mm; and / or the height of the flow-blocking strip is 0.3 - 0.6 mm.

8. The ceramic substrate according to claim 1, characterized in that: The material of the substrate body is at least one of alumina, aluminum nitride and silicon nitride.

9. The ceramic substrate according to claim 1, characterized in that: It further includes a second conductive layer, and the second conductive layer is disposed on the back surface of the substrate body.

10. The ceramic substrate according to claim 9, characterized in that: The first conductive layer and / or the second conductive layer is / are copper foil.

11. A chip packaging structure, characterized in that: It includes the ceramic substrate as described in any one of claims 1 - 10 and chips soldered on the first conductive layer of the ceramic substrate.

12. A method for preparing a ceramic substrate, characterized in that: It includes: Ball-milling and mixing ceramic powder, photoinitiator, dispersant and plasticizer to form a ceramic 3D printing slurry; Using a photocuring 3D printer to print the ceramic 3D printing slurry into a substrate green body. The front surface of the substrate green body has mounting areas, and grooves are provided between adjacent mounting areas. The depth of the grooves is less than the thickness of the substrate body, and a flow-blocking strip extending along the grooves is provided at the bottom of the grooves; Performing a calcination treatment on the substrate green body to obtain a substrate body; Forming a first conductive layer in the mounting areas on the front surface of the substrate body.

13. The preparation method according to claim 12, characterized in that: Before performing the calcination treatment on the substrate green body, it further includes: Performing a debinding treatment on the substrate green body.

14. The preparation method according to claim 13, characterized in that: The ceramic powder includes at least one of alumina, aluminum nitride and silicon nitride; The temperature of the debinding treatment is 200 - 600 °C, and the heating rate is 0.5 - 1.5 °C / min; the temperature of the calcination treatment is 800 - 1750 °C, and the heating rate is 2 - 10 °C / min.

15. The preparation method according to claim 12, characterized in that: Forming a first conductive layer in the mounting areas on the front surface of the substrate body includes: Bonding copper foil on the mounting areas on the front surface of the substrate body by using a direct copper bonding process.

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