Ceramic substrate and chip packaging structure

Abstract

The utility model discloses a ceramic substrate 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 utility model 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 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 has also become increasingly miniaturized.

[0003] Currently, chips and copper-clad ceramic substrates are mainly combined together 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 cause the creepage distance between the upper copper layers to decrease, resulting in a risk of breakdown damage during product use.

[0004] In the prior art, to prevent solder overflow, usually, the printing position of the solder paste needs to maintain a sufficient distance from 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. Utility Model Content

[0005] The purpose of the embodiments of this application is to provide a ceramic substrate 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 multiple 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 a zigzag or wavy line shape.

[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 flow-blocking strip is less than or equal to the depth of the groove.

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

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

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

[0015] Optionally, the ceramic substrate further includes a first 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 are copper foil.

[0017] Secondly, embodiments of this application provide a chip packaging structure, including a ceramic substrate as described above and a chip soldered onto a second conductive layer in the ceramic substrate.

[0018] Compared with prior art, this application has the following advantages:

[0019] In this embodiment, the ceramic substrate includes a substrate body and a first conductive layer. The front side of the substrate body includes multiple mounting areas for mounting chips. The first conductive layer is disposed in the 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 bottom of the grooves is provided. By providing grooves between the chip mounting areas and providing flow-blocking strips extending along the bottom of the grooves, the creepage distance between the upper conductive layers can be effectively increased using the grooves and flow-blocking strips. This reduces the risk of chip breakdown when solder overflow occurs, further shortens the distance limitation between the chip and the edge of the upper conductive layer, thereby reducing the overall size of the ceramic substrate. This meets the trend of semiconductor packaging modules gradually becoming smaller. Therefore, the ceramic substrate provided in this embodiment effectively solves the problem that existing ceramic substrates cannot be further reduced in size due to solder overflow. Attached Figure Description

[0020] Figure 1 This diagram illustrates a traditional chip packaging structure.

[0021] Figure 2 This is a schematic diagram of the substrate body structure provided in the embodiments of this application;

[0022] Figure 3 express Figure 2 A magnified view of a portion of M;

[0023] Figure 4 express Figure 2 Another magnified view of part M;

[0024] Figure 5 This is a schematic diagram of the ceramic substrate structure provided in the embodiments of this application;

[0025] Figure 6 This is a flowchart illustrating the method for preparing the ceramic substrate provided in the embodiments of this application;

[0026] Figure 7 This is a schematic diagram of the chip packaging structure provided in the embodiments of this application. Detailed Implementation

[0027] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0028] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] As semiconductor packaging modules gradually develop towards higher power, integration, and miniaturization, the requirements for chip area and the size of copper-clad ceramic substrates are also increasing. The main functions of copper-clad ceramic substrates in semiconductor packaging modules are to support the chip, provide heat dissipation channels, and provide insulation protection. To match the miniaturization trend of semiconductor packaging devices, copper-clad ceramic substrates should minimize their area while ensuring chip support, thus meeting the demands of product development.

[0031] Currently, chips and copper-clad ceramic substrates are mainly bonded together using high-temperature molten solder. This method requires first printing solder paste onto the upper copper layer of the copper-clad ceramic substrate using a stencil, then placing the chip on top of the solder paste, and finally using a high-temperature reflow soldering process to bond the chip to the copper-clad ceramic substrate. However, because solder paste has a certain fluidity at high temperatures, when the solder paste printing position is close to the edge of the upper copper layer, solder overflow is prone to occur. Figure 1 As shown at point A, solder overflow can reduce the creepage distance between upper copper layers, such as... Figure 1 As shown at point B, this poses a risk of product breakdown and damage during use.

[0032] To prevent solder overflow, it is necessary to maintain a sufficient distance between the solder paste printing position and the edge of the upper copper layer, such as... Figure 1 As shown at point C, this necessitates a corresponding increase in the size of the copper-clad ceramic substrate, which contradicts the current trend of miniaturization in packaging modules and cannot meet the development trend of miniaturization in packaging modules.

[0033] To address the aforementioned problems, this 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 disposed 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 flow-blocking strip 24 extending along the bottom of the groove 23 is provided.

[0034] In the ceramic substrate 20 provided in this application embodiment, the substrate body 21 is made of ceramic, which gives the substrate body 21 excellent thermal conductivity, effectively dissipating the heat generated by high-power devices. The ceramic material of the substrate body 21 also gives it extremely high resistivity and breakdown voltage, providing reliable electrical insulation suitable for high-voltage and high-power applications, preventing arcing and short circuits. Furthermore, the ceramic material of the substrate body 21 gives it high hardness and wear resistance, enabling it to withstand high temperatures, mechanical stress, and vibration, making it suitable for high-reliability applications in harsh environments. Additionally, the ceramic material of the substrate body 21 results in a low coefficient of thermal expansion, allowing it to operate stably in high-temperature environments. It also gives the substrate body 21 excellent corrosion resistance, making it suitable for applications in harsh chemical environments such as acids, alkalis, and humid conditions. Moreover, it has a low dielectric constant and loss factor, making it suitable for high-frequency circuits and radio frequency applications.

[0035] Optionally, the substrate body 21 is made of 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 excellent insulation performance, low coefficient of thermal expansion, dielectric constant and loss factor.

[0036] In the ceramic substrate 20 provided in this application embodiment, the front side of the substrate body 21 is divided into multiple mounting areas 211 by grooves 23. A first conductive layer 22 is provided on each mounting area 211 to facilitate soldering with the chip. The depth of the grooves 23 is less than the thickness of the substrate body 21, that is, the grooves 23 do not penetrate the substrate body 21, which can ensure the overall structural strength of the substrate.

[0037] In this embodiment, the groove 23 is arranged around the mounting area 211, thereby making 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 to 1 mm, for example, one or any two of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm. Optionally, in some embodiments, the depth of the groove 23 is 0.3 to 0.6 mm, for example, one or any two of 0.3 mm, 0.4 mm, 0.5 mm, and 0.6 mm.

[0038] Optionally, the first conductive layer 22 is disposed in the mounting area 211 by means of paving, evaporation plating, bonding, etc., and the chip can be soldered to 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.

[0039] In the embodiment of the present application, the above-mentioned current 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 conductive layers, and relieve the breakdown risk caused by the solder overflow phenomenon.

[0040] Among them, the above-mentioned current 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 current blocking strip 24 has an upper-large and lower-small structure; optionally, in some embodiments, the cross-section of the above-mentioned current 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 increasing the creepage distance between the two conductive layers.

[0041] In the embodiment of the present application, by arranging the groove 23 between the mounting areas 211 and arranging the current blocking strip 24 along the extension of the groove 23 at the bottom of the groove 23, the creepage distance between the upper conductive layers can be effectively increased by using the groove 23 and the current blocking strip 24, the breakdown risk of the chip module when solder overflow occurs is reduced, the distance limit from the chip to the edge of the upper conductive layer is further shortened, the effective use area of the upper copper layer is increased, and thus the overall size of the ceramic substrate 20 is reduced, meeting the trend of the semiconductor packaging module gradually developing towards miniaturization. Therefore, the ceramic substrate 20 provided by 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 solder overflow phenomenon.

[0042] Exemplarily, assuming that the chip size is 4 mm and the solder is also set to 4 mm correspondingly, then at high temperature, the solder may extend and become 5 mm. Assuming that the upper copper layer is only 4.5 mm, then 0.5 mm of solder overflow will occur, which means that the creepage distance between the upper copper layers is reduced and the breakdown risk occurs. The existing technology is to make the size of the upper copper layer larger to ensure that there is enough solder overflow distance from the chip edge to the copper layer edge; while in the embodiment of the present application, a groove 23 is arranged between the copper layers, and a convex current blocking strip 24 is arranged in the groove 23, which can effectively increase the creepage distance between the upper copper layers. Even if solder overflow occurs, as Figure 7 shown at D in the figure, the creepage distance between the copper layers is sufficient to prevent breakdown, so there is no need to ensure that there is enough solder overflow distance from the chip edge to the copper layer edge, thus shortening the distance limit from the chip to the edge of the upper copper layer.

[0043] Optionally, in one embodiment, the width of the flow-blocking strip 24 is smaller than the width of the groove 23 to ensure that the groove 23 can accommodate overflowing solder. Optionally, in one specific embodiment, the width of the groove 23 is 5 to 10 mm, for example, it can be one or more of 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm, or any value between two of them; the width of the flow-blocking strip 24 is 3 to 6 mm, for example, it can be one or more of 3 mm, 4 mm, 5 mm, and 6 mm, or any value between two of them.

[0044] Optionally, in one embodiment, the height of the flow-blocking strip 24 is less than or equal to the depth of the groove 23, which facilitates manufacturing and also ensures that the flow-blocking strip 24 is not easily damaged or detached by impacts under the protection of the groove 23. Optionally, in some specific embodiments, the height of the flow-blocking strip 24 is 0.3 to 0.6 mm, for example, one or any two of 0.3 mm, 0.4 mm, 0.5 mm, and 0.6 mm.

[0045] Alternatively, in one implementation, such as Figures 3-4 As shown, flow-blocking ridges 25 are also provided between the flow-blocking strip 24 and the sidewall of the groove 23, which can further increase the creepage distance between adjacent first conductive layers 22. Optionally, in some embodiments, the flow-blocking ridges 25 are sawtooth or wavy, wherein, to ensure structural strength, the height of a single tooth in the ridge is greater than or equal to 0.1 mm, and the spacing between the teeth is greater than or equal to 0.05 mm.

[0046] Optionally, in one embodiment, the ceramic substrate 20 provided in this application further includes a second conductive layer 26, which is disposed on the back side of the substrate body 21. The second conductive layer 26 is used to support and solder electronic components on the back side of the substrate body 21. Optionally, the second conductive layer is disposed on the back side of the substrate body 21 by means of deposition, vapor deposition, bonding, etc., and electronic components can be soldered onto the second conductive layer using solder. The second conductive layer can be a copper layer structure such as copper foil, which is convenient for processing and fabrication by means of vapor deposition, bonding, etc., making the ceramic substrate 20 provided in this application an example of a double-sided copper-clad ceramic substrate 20.

[0047] Please see Figure 6 The diagram shows a flowchart of a method for preparing a ceramic substrate according to an embodiment of this application, which includes steps 601 to 604.

[0048] Step 601: Ball mill and mix ceramic powder, photoinitiator, dispersant and plasticizer to form ceramic 3D printing slurry.

[0049] In step 601, the ceramic powder can be one or more of alumina, aluminum nitride, and silicon nitride. Optionally, by mass, the ceramic powder can include 80-95 parts of submicron-sized ceramic powder and 3-10 parts of nano-sized ceramic powder. Considering that smaller particle size results in stronger sintering performance, but also stronger agglomeration ability, and better sintering performance makes the material easier to sinter densely, resulting in better strength and toughness, but strong agglomeration ability can lead to additives not being uniformly dispersed in the matrix, in this embodiment, the ceramic powder includes both submicron-sized and nano-sized ceramic powder. Under the above mass ratio, submicron-sized ceramic powder has better sintering performance, while nano-sized ceramic powder can help the matrix to sinter densely.

[0050] Optionally, in one embodiment, the particle size of the submicron-sized ceramic powder can be 0.05–0.5 μm, while the particle size of the nano-sized ceramic powder can be 0.01–0.05 μm.

[0051] Optionally, in one embodiment, the ceramic powder further includes La2O3 powder and SiC whisker powder. The addition of La2O3 powder and SiC whisker powder to the ceramic powder matrix can provide rod-like toughening, which can improve the toughness and flexural strength of the alumina matrix.

[0052] Optionally, in one specific embodiment, the ceramic powder comprises, by weight, 80-95 parts of submicron-sized Al2O3 powder, 3-10 parts of nano-sized Al2O3 powder, 1-5 parts of La2O3 powder, and 1-5 parts of SiC whisker powder. The La2O3 powder, SiC whisker powder, and nano-sized Al2O3 powder are all additives. Adding La2O3 powder and SiC whisker powder to the alumina matrix can provide rod-like toughening, but it will reduce the density of the alumina matrix. Rod-like toughening can improve the toughness and flexural strength of the alumina matrix. A small amount of nano-sized Al2O3 powder can help the alumina matrix to be sintered and densified more easily, and can also improve the toughness and flexural strength of the alumina matrix. Under the above weight ratio, both the rod-like toughening effect and the density of the alumina matrix are ensured, in order to prepare a high-strength and tough alumina substrate.

[0053] Optionally, the particle size of the La2O3 powder and SiC whisker powder can be 0.05 to 0.5 μm, and the overall effect of additives within this particle size range is better.

[0054] In step 601 above, the photosensitive resin, photoinitiator, dispersant and plasticizer can be components known in the field of 3D printing. The ceramic powder, photosensitive resin, photoinitiator, dispersant and plasticizer are added to the 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 produce a ceramic slurry suitable for photopolymerization 3D printing.

[0055] Step 602: Using a photopolymer 3D printer, the ceramic 3D printing paste is printed onto a substrate blank. The front side of the substrate blank has a mounting area, and a groove is provided adjacent to the mounting area. The depth of the groove is less than the thickness of the substrate body, and a flow-blocking strip extending along the bottom of the groove is provided.

[0056] In step 602, the ceramic 3D printing slurry is placed in the material tank of the photopolymer 3D printer; then, based on the design requirements that the front has a mounting area, the adjacent mounting areas have grooves, the depth of the grooves is less than the thickness of the substrate body, and the bottom of the grooves is provided with flow-blocking strips extending along the grooves, the modeling and slicing of the ceramic substrate is first completed by computer software, and then the substrate blank is manufactured by layer exposure and layer stacking.

[0057] Step 603: Calcine the substrate blank to obtain the substrate body.

[0058] In step 603, the substrate blank is placed in a sintering furnace under a protective gas atmosphere for sintering to obtain the substrate body.

[0059] Step 604: Form a first conductive layer in the mounting area on the front side of the substrate body.

[0060] In step 604, a metal layer is formed on the mounting area on the front side of the substrate body by means of laying, vapor deposition, bonding, etc., which can serve as the first conductive layer mentioned above.

[0061] The control method provided in this application involves ball milling and mixing ceramic powder, photoinitiator, dispersant, and plasticizer into a ceramic 3D printing slurry. Then, a substrate blank is fabricated using 3D printing. This blank has a mounting area on the front side, adjacent mounting areas with grooves, the depth of which is less than the thickness of the substrate body, and a flow-blocking strip extending along the bottom of the groove. A first conductive layer is then formed on the mounting area on the front side through calcination. This allows the prepared ceramic substrate to effectively increase the creepage distance between the upper conductive layers using the grooves and flow-blocking strips, reducing the risk of chip module breakdown when solder overflow occurs. It further shortens the distance limitation between the chip and the edge of the upper conductive layer, thereby reducing the overall size of the ceramic substrate. This meets the trend of semiconductor packaging modules gradually becoming smaller. Therefore, the ceramic substrate provided in this application effectively solves the problem that existing ceramic substrates cannot be further reduced in size due to solder overflow.

[0062] Optionally, in one embodiment, at least one of aluminum oxide, aluminum nitride, and silicon nitride enables the substrate body to not only have high thermal conductivity, but also excellent insulation properties, low coefficient of thermal expansion, low dielectric constant, and low loss factor.

[0063] Optionally, in one specific embodiment, when the ceramic powder comprises 80-95 parts by weight of submicron-sized Al2O3 powder, 3-10 parts by weight of nano-sized Al2O3 powder, 1-5 parts by weight of La2O3 powder, and 1-5 parts by weight of SiC whisker powder, the calcination temperature is 800-1750°C and the heating rate is 2-10°C / min. This effectively balances sintering efficiency and reduces surface cracks, ensuring the structural strength of the substrate. Optionally, the calcination process is as follows: in a nitrogen atmosphere, the temperature is raised to 800-1200°C at a rate of 5-10°C / min; then raised to 1600-1750°C at a rate of 2-5°C / min and held for 2-4 hours; subsequently, the temperature is lowered to 800-1200°C at a rate of 2-10°C / min; finally, the temperature is cooled to room temperature in the furnace to obtain the Al2O3-based ceramic substrate.

[0064] Optionally, in one embodiment, before calcining the substrate blank, the process further includes:

[0065] The substrate blank is degreased.

[0066] In this embodiment, the ceramic substrate blank is placed in a vacuum degreasing furnace or other equipment for degreasing treatment before calcination, which can completely volatilize the photosensitive resin, photoinitiator, dispersant and plasticizer in the ceramic blank, thereby improving product quality.

[0067] Optionally, in one specific embodiment, when the ceramic powder comprises 80-95 parts by weight of submicron-sized Al2O3 powder, 3-10 parts by weight of nano-sized Al2O3 powder, 1-5 parts by weight of La2O3 powder, and 1-5 parts by weight of SiC whisker powder, the degreasing temperature is 200-600°C and the heating rate is 0.5-1.5°C / min, which can effectively balance degreasing efficiency and reduce surface cracks, ensuring the structural strength of the substrate body. Optionally, the degreasing process is as follows: in a nitrogen atmosphere, the temperature is increased to 200–220°C at a rate of 0.5–1.5°C / min and held for 0.5–3 h; then the temperature is increased to 320–380°C at a rate of 0.5–1.5°C / min and held for 0.5–3 h; subsequently, the temperature is increased to 550–600°C at a rate of 0.5–1.5°C / min and held for 0.5–2 h; finally, the temperature is cooled to room temperature in the furnace to obtain a degreased Al2O3-based ceramic substrate blank.

[0068] Optionally, in one specific embodiment, the fabrication method provided in this application, which forms a first conductive layer in the mounting area on the front side of the substrate body, includes:

[0069] The copper foil is bonded to the mounting area on the front side of the substrate using a direct copper bonding process.

[0070] In this specific embodiment, the direct copper bonding (DCB) process is used to bond the substrate body to the copper foil to obtain a high-strength and tough copper-clad ceramic substrate on the front side.

[0071] In this specific embodiment, the direct copper bonding process, with a temperature of 1000-1100℃, a pressure of 20-40MPa, and a processing time of 10-30 minutes, can bond copper foil to the front side of the ceramic substrate.

[0072] Optionally, in one embodiment, the preparation method provided in this application further includes:

[0073] A second conductive layer is formed on the back side of the substrate body.

[0074] In this embodiment, a metal layer is formed on the mounting area on the front side of the substrate body by means of laying, vapor deposition, bonding, etc., which can serve as the second conductive layer. The second conductive layer is used to support and solder electronic components on the back side of the substrate body.

[0075] Optionally, in one specific embodiment, a second conductive layer is formed on the back side of the substrate body, comprising:

[0076] Copper foil is bonded to the back side of the substrate body using a direct copper bonding process.

[0077] In this specific embodiment, the direct copper bonding (DCB) process is used to bond the substrate body to the copper foil to obtain a high-strength and tough double-sided copper-clad ceramic substrate.

[0078] In this specific embodiment, the direct copper bonding process, with a temperature of 1000-1100℃, a pressure of 20-40MPa, and a processing time of 10-30 minutes, can bond copper foil to the back of the ceramic substrate.

[0079] This application also provides a chip packaging structure 100, such as... Figure 7 As shown, it includes a ceramic substrate 20 as described above and a chip 30 soldered to a first conductive layer in the ceramic substrate 10. The chip 30 can be soldered to the first conductive layer 22 on the front side of the ceramic substrate 20 via a solder layer 31.

[0080] The above-described chip packaging structure embodiment includes the aforementioned ceramic substrate and achieves the same technical effect. To avoid repetition, it will not be described again here. For relevant details, please refer to the description of the ceramic substrate embodiment.

[0081] The chip packaging structure provided in this application embodiment has grooves between the mounting areas of the ceramic substrate, and a flow-blocking strip extending along the bottom of the grooves. The grooves and flow-blocking strips can effectively increase the creepage distance between the upper conductive layers, reduce the risk of chip module breakdown when solder overflow occurs, and further shorten the distance limitation between the chip and the edge of the upper conductive layer. This reduces the overall size of the ceramic substrate and meets the trend of semiconductor packaging modules gradually becoming smaller. Therefore, the ceramic substrate provided in this application embodiment effectively solves the problem that the size of existing ceramic substrates cannot be further reduced due to solder overflow.

[0082] To make the inventive objectives, technical solutions, and beneficial effects of this application clearer, the present application is further described below with reference to embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application.

[0083] The present application will be described in detail below through embodiments.

[0084] Example 1

[0085] (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, an Al2O3-based ceramic powder is obtained.

[0086] (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 an Al2O3-based ceramic 3D printing slurry.

[0087] (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 '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.

[0088] (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.

[0089] (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.

[0090] (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.

[0091] Example 2

[0092] (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 absolute 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.

[0093] (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.

[0094] (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 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 an upper - large - lower - small structure, 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.

[0095] (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.

[0096] (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.

[0097] (6) Adopt the DCB process to bond the front - side 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.

[0098] Example 3

[0099] (1) Weigh 95 parts by mass of Al2O3 powder with a particle size of 0.1 - 0.5 μm, 3 parts by mass of nano-Al2O3 powder with a particle size of 0.01 - 0.05 μm, 1 part 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.

[0100] (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 the Al2O3-based ceramic 3D printing slurry.

[0101] (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 'gan'. 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.

[0102] (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.

[0103] (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.

[0104] (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.

[0105] Example 4

[0106] (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, and then dry to obtain Al2O3 - based ceramic powder;

[0107] (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;

[0108] (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 'Wang'. First, complete the modeling and slicing of the ceramic substrate by computer software, and then manufacture the Al2O3 - based ceramic substrate blank by means of layer - by - layer exposure and stacking;

[0109] (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 to room temperature with the furnace;

[0110] (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 to 1200 °C at a rate of 10 °C / min; finally, cool to room temperature with the furnace to obtain the Al2O3 - based ceramic substrate;

[0111] (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.

[0112] Example 5

[0113] (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, an Al2O3 - based ceramic powder is obtained.

[0114] (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.

[0115] (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 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, 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 an Al2O3 - based ceramic substrate blank is manufactured by means of layer - by - layer exposure and stacking.

[0116] (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 1.0 °C / min to 210 °C and hold for 0.5 h; then heat it at a rate of 1.0 °C / min to 320 °C and hold for 0.5 h; heat it at a rate of 1.0 °C / min to 600 °C and hold for 0.5 h; finally, cool it to room temperature with the furnace.

[0117] (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 7.5 °C / min to 1000 °C; then heat it at a rate of 2 °C / min to 1600 °C and hold for 3 h; subsequently, cool it at a rate of 6 °C / min to 1000 °C; finally, cool it to room temperature with the furnace to obtain an Al2O3 - based ceramic substrate.

[0118] (6) Adopt the DCB process to bond the front - side 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.

[0119] Example 6

[0120] (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 mixing and 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.

[0121] (2) Weigh a certain amount of silicon nitride-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 a silicon nitride-based ceramic 3D printing slurry.

[0122] (3) Place the silicon nitride-based ceramic 3D printing slurry in the material tank of a light-curing 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, and the cross-section of the flow-blocking strip is in the shape of a Chinese character '王'. First, the computer software completes the modeling and slicing of the ceramic substrate, and then a silicon nitride-based ceramic substrate blank is manufactured by means of layer-by-layer exposure and stacking.

[0123] (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 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.

[0124] (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 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 a silicon nitride-based ceramic substrate.

[0125] (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.

[0126] Example 7

[0127] (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, and then dry to obtain Al2O3 - based ceramic powder;

[0128] (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;

[0129] (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 'gan'. First, complete the modeling and slicing of the ceramic substrate by computer software, and then manufacture the Al2O3 - based ceramic substrate blank by means of layer - by - layer exposure and stacking;

[0130] (4) Place the obtained Al2O_{3}-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;

[0131] (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;

[0132] (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.

[0133] Example 8

[0134] (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 absolute 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.

[0135] (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.

[0136] (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, the cross-section of the flow-blocking strip is in the shape of the Chinese character '王' (king), 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, 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.

[0137] (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.

[0138] (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.

[0139] (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.

[0140] Example 9

[0141] (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 medium and absolute ethanol as 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.

[0142] (2) Weigh a certain amount of Al2O3-based ceramic powder, photosensitive resin, photoinitiator, dispersant, and plasticizer. Add 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.

[0143] (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 0.5 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 top and a smaller bottom, and the cross-section of the flow-blocking strip is in the shape of a Chinese character '王'. 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.

[0144] (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.

[0145] (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.

[0146] (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.

[0147] Example 10

[0148] (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 medium and anhydrous ethanol as 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.

[0149] (2) Weigh a certain amount of Al2O3-based ceramic powder, photosensitive resin, photoinitiator, dispersant, and plasticizer. Add 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.

[0150] (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 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.

[0151] (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.

[0152] (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.

[0153] (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.

[0154] Example 11

[0155] (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.

[0156] (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.

[0157] (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 top and a smaller bottom, 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.

[0158] (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.

[0159] (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.

[0160] (6) Adopt the DCB process to bond the front mounting area and the back of the Al2O3 ceramic substrate to the copper foil respectively, and finally obtain a high-strength and tough double-sided copper-clad alumina ceramic substrate.

[0161] Tests have shown that, compared to existing ceramic substrates without grooves and flow barriers, the ceramic substrates prepared in Examples 1-11 can significantly increase the creepage distance between the upper conductive layers, effectively reducing the risk of breakdown when the chip soldered on the conductive layer experiences solder overflow.

[0162] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0163] The above provides a detailed description of a ceramic substrate, its preparation method, and chip packaging structure provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A ceramic substrate, characterized by, The ceramic substrate comprises a substrate body and a first conductive layer, the front surface of the substrate body comprises a plurality of mounting areas for mounting chips, the first conductive layer is arranged on 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 the bottom of the groove is provided with a flow resistance strip extending along the groove.

2. The ceramic substrate of claim 1, wherein, The flow resistance strip has a structure of large at the top and small at the bottom; and / or the cross section of the flow resistance strip has a shape of Wang, Gan, umbrella, tree or antenna.

3. The ceramic substrate of claim 1, wherein, A flow resistance ridge is further arranged between the flow resistance strip and the side wall of the groove.

4. The ceramic substrate of claim 3, wherein, The flow resistance ridge has a sawtooth shape or a wavy line.

5. The ceramic substrate of claim 1, wherein, The width of the flow resistance strip is less than the width of the groove; and / or the height of the flow resistance strip is less than or equal to the depth of the groove.

6. The ceramic substrate of claim 1, wherein, The width of the groove is 5-10 mm; and / or the width of the flow resistance strip is 3-6 mm.

7. The ceramic substrate of claim 1, wherein, The thickness of the substrate body is 0.5-1 mm; and / or the height of the flow resistance strip is 0.3-0.6 mm.

8. The ceramic substrate of claim 1, wherein, A second conductive layer is further arranged on the back surface of the substrate body.

9. The ceramic substrate of claim 8, wherein, The first conductive layer and / or the second conductive layer is a copper foil.

10. A chip package structure, comprising: The ceramic substrate comprises a substrate body and a first conductive layer, the front surface of the substrate body comprises a plurality of mounting areas for mounting chips, the first conductive layer is arranged on 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 the bottom of the groove is provided with a flow resistance strip extending along the groove. The flow resistance strip has a structure of large at the top and small at the bottom; and / or the cross section of the flow resistance strip has a shape of Wang, Gan, umbrella, tree or antenna. A flow resistance ridge is further arranged between the flow resistance strip and the side wall of the groove. The flow resistance ridge has a sawtooth shape or a wavy line. The width of the flow resistance strip is less than the width of the groove; and / or the height of the flow resistance strip is less than or equal to the depth of the groove. The width of the groove is 5-10 mm; and / or the width of the flow resistance strip is 3-6 mm. The thickness of the substrate body is 0.5-1 mm; and / or the height of the flow resistance strip is 0.3-0.6 mm. A second conductive layer is further arranged on the back surface of the substrate body. The first conductive layer and / or the second conductive layer is a copper foil. The ceramic substrate comprises a substrate body and a first conductive layer, the front surface of the substrate body comprises a plurality of mounting areas for mounting chips, the first conductive layer is arranged on 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 the bottom of the groove is provided with a flow resistance strip extending along the groove. The flow resistance strip has a structure of large at the top and small at the bottom; and / or the cross section of the flow resistance strip has a shape of Wang, Gan, umbrella, tree or antenna. A flow resistance ridge is further arranged between the flow resistance strip and the side wall of the groove. The flow resistance ridge has a sawtooth shape or a wavy line. The width of the flow resistance strip is less than the width of the groove; and / or the height of the flow resistance strip is less than or equal to the depth of the groove. The width of the groove is 5-10

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