Ceramic substrate tape casting method based on light-humidity dual-curing system

Abstract

The invention belongs to the field of ceramic substrate manufacturing, and particularly relates to a ceramic substrate tape casting method based on a light-humidity dual-curing system, which comprises the following steps: S1, preparing raw materials; s2, preparing slurry; s3, adding a cross-linking agent; s4, defoaming treatment is carried out; s5, carrying out tape casting; s6, primary curing; s7, carrying out drying treatment; and S8, sintering treatment. According to the ceramic substrate tape casting method based on the light-humidity dual-curing system, ethyl acetate and butyl acetate are used as solvents and are harmless to human bodies and the environment, organic solvents such as ethyl acetate have small surface tension, capillary force caused in the drying process is small, a tape casting green body can be effectively prevented from being dried and cracked, and the service life of the tape casting green body is prolonged. The EBECRYL series acrylic acid cross-linking agent is used as the curing agent, the addition amount of effective components is small (smaller than 5%), good flexibility is achieved after preliminary curing, safe cutting of the tape-casting green body can be achieved, and the tape-casting green body can be stored easily.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic substrate manufacturing, in particular to a ceramic substrate tape casting method based on a light-moisture dual-curing system. Background Art

[0002] With the rapid development of semiconductor lighting, power electronics, microwave radio frequency, 5G communications, and new energy vehicles, heat dissipation has become one of the key factors affecting the performance of power devices. The effective life of a power device is negatively correlated with its operating temperature. Every 10°C increase will reduce its effective life by 30-50%. In the field of high-power LED packaging, only 20-30% of the energy is converted into light energy, and the rest is converted into heat energy. Therefore, the packaging substrate needs to have high thermal conductivity, good thermal stability, and a thermal expansion coefficient that matches the chip material. Ceramic materials are ideal for heat dissipation devices for functional components because of their similar thermal expansion coefficient to that of functional devices and their high thermal conductivity.

[0003] At present, the ceramic sheets prepared by the tape casting process have good uniformity and high permeability, and the required equipment and operation are simple, the product quality is stable, and the process is continuous and suitable for large-scale production. It has now become a pillar technology for the production of ceramic substrates. However, although water-based tape casting is environmentally friendly and low-cost, it has problems such as low drying efficiency, difficulty in degassing, and low green body strength, and cannot be used for large-scale production. Organic tape casting often requires the addition of a large amount (>10%) of organic binder, which brings difficulties to the subsequent debinding and sintering process, seriously affecting the performance of the substrate, and the use of a large amount of organic solvents is harmful to the environment and the health of operators. In view of this, we propose a tape casting method for ceramic substrates based on a light-wet dual-curing system. Summary of the invention

[0004] The main purpose of the present invention is to provide a ceramic substrate tape casting method based on a light-moisture dual-curing system, which can solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides a ceramic substrate tape casting method based on a light-moisture dual-curing system, comprising the following steps:

[0006] S1. Raw material preparation;

[0007] S2, slurry preparation;

[0008] S3, adding a cross-linking agent;

[0009] S4, defoaming treatment;

[0010] S5, tape casting;

[0011] S6, initial curing;

[0012] S7, drying treatment;

[0013] S8. Sintering treatment.

[0014] Preferably, in step S1, ceramic powder, solvent and dispersant are weighed in proportion, wherein the ceramic powder is any one of aluminum oxide, zirconium oxide, silicon carbide and silicon nitride; the solvent is any one of ethyl acetate and butyl acetate; the dispersant is any one of BYK series dispersants; the ceramic powder accounts for 60-80%, the solvent accounts for 10-30%, and the dispersant accounts for 0.1-1%.

[0015] Preferably, in step S2, the ceramic powder is placed in a ball mill for ball milling, and the ball-milled ceramic powder is mixed with a dispersant and a solvent to obtain a slurry, and the slurry is stirred. The ball milling medium is any one of alumina balls, zirconia balls, and silicon nitride balls. The ball milling time is 2-10 hours, and the material: ball = 1:1-3.

[0016] Preferably, in step S3, an EBECRYL series acrylic crosslinking agent is added to the uniformly mixed slurry, and then ball milling is continued to obtain a slurry, wherein the addition amount of the EBECRYL series acrylic crosslinking agent is 5-15% of the mass of the powder, the ball milling time is 2-10 minutes, and the EBECRYL series acrylic crosslinking agent is preferably an acrylic crosslinking agent EBECRYL-4765.

[0017] Preferably, in step S4, the ball-milled slurry is poured into a vacuum degassing device for degassing, the degassing time is 15-30 minutes, and the vacuum degree is 100Pa-1000Pa.

[0018] Preferably, in step S5, the scraper height of the tape casting machine is adjusted according to demand, and then the slurry is poured into the tape casting slurry tank on the tape casting machine.

[0019] Preferably, after ensuring that the scraper is in the correct position in step S5, the power is started, and the slurry in the casting slurry tank is driven forward by the parallel movement of the plastic film belt, and a layer of film is formed by the casting scraper, wherein the plastic film is a silicone oil-modified PET film, the scraper height is 1-3 mm, and the moving rate is 5-20 mm / s.

[0020] Preferably, in step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 0.5-2 hours, and the solidification temperature is 20-40°C.

[0021] Preferably, in step S7, the preliminarily solidified tape-cast green body is cut into a suitable size and then transferred to an oven for drying at a temperature of 30° C. to 60° C. for a drying time of 2 to 10 hours.

[0022] Preferably, in step S8, the dried green body is taken out of the oven and placed in a sintering furnace for sintering. The sintering method is pressureless sintering or gas pressure sintering. The sintering temperature is 1000-2300°C. The holding time is 2-5h. The sintering atmosphere is any one of air atmosphere, nitrogen atmosphere or argon atmosphere. The heating rate between 0-600°C is 0.1-0.5°C / min, and the heating rate from 600°C to the sintering temperature is 0.5-5°C / min.

[0023] The present invention provides a ceramic substrate tape casting method based on a light-moisture dual-curing system. It has the following beneficial effects:

[0024] (1) The ceramic substrate tape-casting molding method based on the light-moisture dual-curing system uses ethyl acetate and butyl acetate as solvents, which are harmless to the human body and the environment, and have good wettability to ceramic powders, and can prepare ceramic slurries with high solid content. At the same time, organic solvents such as ethyl acetate have a small surface tension, and the capillary force caused during the drying process is small, which can effectively avoid the drying and cracking of the tape-cast green body, and it is easy to achieve safe and efficient drying and batch continuous preparation of the green body.

[0025] (2) The ceramic substrate tape-casting molding method based on the light-moisture dual-curing system uses the EBECRYL series acrylic cross-linking agent as a curing agent, which has the characteristics of light / moisture dual curing, a small amount of effective ingredients added (<5%), good flexibility after initial curing, and can achieve safe cutting of the tape-cast green body. The full curing agent can have a higher green body strength, which is beneficial to the preservation of the tape-cast green body.

[0026] (3) The ceramic substrate tape casting method based on the light-moisture dual-curing system also helps to suppress cracking and deformation defects caused by the subsequent debinding and sintering process because it uses a smaller amount of binder, and can prepare high-quality ceramic substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of the process of the present invention.

[0029] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Embodiment 1

[0032] See also Figure 1 The present invention proposes a ceramic substrate tape-casting method based on a light-moisture dual-curing system, comprising the following steps: S1, raw material preparation; S2, slurry preparation; S3, adding a cross-linking agent; S4, defoaming treatment; S5, tape-casting; S6, preliminary curing; S7, drying treatment; S8, sintering treatment.

[0033] In step S1, weigh 2000 g of alumina powder (Alteo, PL172LSB), 20 g of BYK-170 dispersant, 450 g of ethyl acetate and 4000 g of alumina balls.

[0034] In step S2, the material weighed in step S1 is placed in a ball mill for ball milling. The ball milling time is 3 hours and the rotation speed is 200 r / min.

[0035] In step S3, 180 g of acrylic crosslinking agent EBECRYL-4765 is added to the uniformly mixed slurry, and ball milling is continued for 5 minutes to obtain a slurry;

[0036] In step S4, the ball-milled slurry is poured into a vacuum defoaming device, the defoaming time is 20 minutes, and the vacuum degree is 1000 Pa;

[0037] In step S5, the height of the scraper of the tape casting machine is adjusted, the defoamed slurry is poured into the tape casting slurry tank, the power is turned on, and the slurry in the slurry tank is driven forward by the parallel movement of the PET film, and a film is formed by the tape casting scraper. The scraper height is 1.5 mm and the moving speed is 10 mm / s.

[0038] In step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 1 hour, and the solidification temperature is 30° C.;

[0039] In step S7, the preliminarily solidified tape-cast green body is cut into 120*120 mm, and then transferred to an oven for drying at a temperature of 50° C. for 5 h.

[0040] In step S8, the dried green body is taken out from the oven and placed in a sintering furnace for sintering. The sintering method is pressureless sintering, the sintering temperature is 1600°C, the holding time is 2h, the sintering atmosphere is air atmosphere, the heating rate between 0-600°C is 0.5°C / min, and the heating rate between 600°C and sintering temperature is 1°C / min;

[0041] Embodiment 2

[0042] See also Figure 1 , the present invention proposes a ceramic substrate tape casting method based on a light-moisture dual-curing system;

[0043] In step S1, 2000 g of alumina powder (Alteo, PL172LSB), 20 g of BYK-170 dispersant, 400 g of ethyl acetate and 4000 g of alumina balls were weighed;

[0044] In step S2, the material weighed in step S1 is placed in a ball mill for ball milling. The ball milling time is 3 hours and the rotation speed is 200 r / min.

[0045] In step S3, 150 g of acrylic crosslinking agent EBECRYL-4765 is added to the uniformly mixed slurry, and ball milling is continued for 5 minutes to obtain a slurry;

[0046] In step S4, the ball-milled slurry is poured into a vacuum defoaming device, the defoaming time is 25 minutes, and the vacuum degree is 1000 Pa;

[0047] In step S5, the height of the scraper of the tape casting machine is adjusted, the defoamed slurry is poured into the tape casting slurry tank, the power is turned on, and the slurry in the slurry tank is driven forward by the parallel movement of the PET film, and a film is formed by the tape casting scraper. The scraper height is 1 mm and the moving speed is 10 mm / s.

[0048] In step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 1 hour, and the solidification temperature is 30° C.;

[0049] In step S7, the preliminarily solidified tape-cast green body is cut into 150*150 mm, and then transferred to an oven for drying at a temperature of 50° C. for 3 h.

[0050] In step S8, the dried green body is taken out from the oven and placed in a sintering furnace for sintering. The sintering method is pressureless sintering, the sintering temperature is 1600°C, the holding time is 2h, the sintering atmosphere is air atmosphere, the heating rate between 0-600°C is 0.5°C / min, and the heating rate between 600°C and sintering temperature is 2°C / min;

[0051] Embodiment 3

[0052] See also Figure 1 , the present invention proposes a ceramic substrate tape casting method based on a light-moisture dual-curing system;

[0053] In step S1, 2800 g of silicon nitride powder (Cixi, H08), 60 g of magnesium oxide (Sinopharm), 140 g of yttrium oxide (McLean), 30 g of BYK-170 dispersant, 850 g of ethyl acetate and 6000 g of silicon nitride balls were weighed;

[0054] In step S2, the material weighed in step S1 is placed in a ball mill for ball milling. The ball milling time is 5 hours and the rotation speed is 200 r / min.

[0055] In step S3, 300 g of acrylic crosslinking agent EBECRYL-4765 is added to the uniformly mixed slurry, and ball milling is continued for 5 minutes to obtain a slurry;

[0056] In step S4, the ball-milled slurry is poured into a vacuum defoaming device, the defoaming time is 25 minutes, and the vacuum degree is 1000 Pa;

[0057] In step S5, the height of the scraper of the tape casting machine is adjusted, the defoamed slurry is poured into the tape casting slurry tank, the power is turned on, and the slurry in the slurry tank is driven forward by the parallel movement of the PET film, and a film is formed by the tape casting scraper. The scraper height is 1.5 mm and the moving speed is 10 mm / s.

[0058] In step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 1 hour, and the solidification temperature is 30° C.;

[0059] In step S7, the preliminarily solidified tape-cast green body is cut into 150*150 mm, and then transferred to an oven for drying at a temperature of 50° C. for 3 h.

[0060] In step S8, the dried green body is taken out from the oven and placed in a sintering furnace for sintering. The sintering method is gas pressure sintering, the sintering temperature is 1850°C, the holding time is 6 hours, the sintering atmosphere is nitrogen atmosphere, the heating rate between 0-600°C is 0.5°C / min, and the heating rate from 600°C to the sintering temperature is 1°C / min.

[0061] A comparative example 1 is also provided;

[0062] In step S1, 2000 g of alumina powder (Alteo, PL172LSB), 20 g of BYK-170 dispersant, 180 g of ethanol, 180 g of ethyl acetate, 180 g of butyl acetate and 4000 g of alumina balls were weighed;

[0063] In step S2, the material weighed in step S1 is placed in a ball mill for ball milling. The ball milling time is 3 hours and the rotation speed is 200 r / min.

[0064] In step S3, 100 g of polyvinyl butyral and 80 g of dibutyl phthalate are added to the uniformly mixed slurry, and ball milling is continued for 3 h to obtain a slurry;

[0065] In step S4, the ball-milled slurry is poured into a vacuum defoaming device, the defoaming time is 20 minutes, and the vacuum degree is 1000 Pa;

[0066] In step S5, the height of the scraper of the tape casting machine is adjusted, the defoamed slurry is poured into the tape casting slurry tank, the power is turned on, and the slurry in the slurry tank is driven forward by the parallel movement of the PET film, and a film is formed by the tape casting scraper. The scraper height is 1.5 mm and the moving speed is 10 mm / s.

[0067] In step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 1 hour, and the solidification temperature is 30° C.;

[0068] In step S7, the preliminarily solidified tape-cast green body is cut into 120*120 mm, and then transferred to an oven for drying at a temperature of 50° C. for 5 h.

[0069] In step S8, the dried green body is taken out from the oven and placed in a sintering furnace for sintering. The sintering method is pressureless sintering, the sintering temperature is 1600°C, the holding time is 2h, the sintering atmosphere is air atmosphere, the heating rate between 0-600°C is 0.5°C / min, and the heating rate between 600°C and sintering temperature is 1°C / min;

[0070] The difference between Comparative Example 1 and Example 1 is that conventional PVB adhesive is used instead of acrylic crosslinking agent EBECRYL-4765;

[0071] A comparative example 2 is also provided;

[0072] See also Figure 1 The present invention proposes a ceramic substrate tape casting method based on a light-moisture dual-curing system, comprising the following steps:

[0073] In step S1, 2000 g of alumina powder (Alteo, PL172LSB), 20 g of BYK-170 dispersant, 400 g of ethyl acetate, 400 g of butyl acetate and 4000 g of alumina balls were weighed;

[0074] In step S2, the material weighed in step S1 is placed in a ball mill for ball milling. The ball milling time is 3 hours and the rotation speed is 200 r / min.

[0075] In step S3, 240 g of polyvinyl butyral and 150 g of dibutyl phthalate are added to the uniformly mixed slurry, and ball milling is continued for 3 h to obtain a slurry;

[0076] In step S4, the ball-milled slurry is poured into a vacuum defoaming device, the defoaming time is 20 minutes, and the vacuum degree is 1000 Pa;

[0077] In step S5, the height of the scraper of the tape casting machine is adjusted, the defoamed slurry is poured into the tape casting slurry tank, the power is turned on, and the slurry in the slurry tank is driven forward by the parallel movement of the PET film, and a film is formed by the tape casting scraper. The scraper height is 1.5 mm and the moving speed is 10 mm / s.

[0078] In step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 1 hour, and the solidification temperature is 30° C.;

[0079] In step S7, the preliminarily solidified tape-cast green body is cut into 120*120 mm, and then transferred to an oven for drying at a temperature of 50° C. for 5 h.

[0080] In step S8, the dried green body is taken out from the oven and placed in a sintering furnace for sintering. The sintering method is pressureless sintering, the sintering temperature is 1600°C, the holding time is 2h, the sintering atmosphere is air atmosphere, the heating rate between 0-600°C is 0.5°C / min, and the heating rate between 600°C and sintering temperature is 2°C / min;

[0081] Comparative Example 2 differs from Comparative Example 1 in that the solvent and binder contents are significantly increased.

[0082] Comparative Example 3 is also provided

[0083] In step S1, 2800 g of silicon nitride powder (Cixi, H08), 60 g of magnesium oxide (Sinopharm), 140 g of yttrium oxide (McLean), 20 g of BYK-170 dispersant, 800 g of ethanol, 800 g of ethyl acetate, 800 g of butyl acetate and 6000 g of silicon nitride balls were weighed;

[0084] In step S2, the material weighed in step S1 is placed in a ball mill for ball milling. The ball milling time is 5 hours and the rotation speed is 200 r / min.

[0085] In step S3, 420 g of polyvinyl butyral and 250 g of dibutyl phthalate are added to the uniformly mixed slurry, and ball milling is continued for 3 h to obtain a slurry;

[0086] In step S4, the ball-milled slurry is poured into a vacuum defoaming device, the defoaming time is 25 minutes, and the vacuum degree is 1000 Pa;

[0087] In step S5, the height of the scraper of the tape casting machine is adjusted, the defoamed slurry is poured into the tape casting slurry tank, the power is turned on, and the slurry in the slurry tank is driven forward by the parallel movement of the PET film, and a film is formed by the tape casting scraper. The scraper height is 1.5 mm and the moving speed is 10 mm / s.

[0088] In step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 1 hour, and the solidification temperature is 30° C.;

[0089] In step S7, the preliminarily solidified tape-cast green body is cut into 120*120 mm, and then transferred to an oven for drying at a temperature of 50° C. for a drying time of 3 h;

[0090] In step S8, the dried green body is taken out from the oven and placed in a sintering furnace for sintering. The sintering method is gas pressure sintering, the sintering temperature is 1850°C, the holding time is 6 hours, the sintering atmosphere is nitrogen atmosphere, the heating rate between 0-600°C is 0.5°C / min, and the heating rate from 600°C to the sintering temperature is 1°C / min.

[0091] The difference between Comparative Example 3 and Example 3 is that the content of solvent and binder is significantly increased.

[0092] Table 1 Performance test table of Examples 1-3 and Comparative Examples 1-3

[0093]

[0094] It can be seen from Table 1 that the relative density of the alumina ceramic substrates of Examples 1 to 2 is at least 99.2%, the bending strength is at least 415 MPa, the Vickers hardness is at least 16.3 GPa, and the thermal conductivity is at least 32 W / (K·m); the relative density of the silicon nitride ceramic substrate of Example 3 is 98.7%, the hardness is 14.8 GPa, the bending strength is 891 MPa, and the thermal conductivity is at least 78 W / (K·m); the bending strength of the alumina ceramic substrate of Comparative Examples 1-2 is at most 355 MPa. a, the Vickers hardness is up to 15.7 GPa, the thermal conductivity is up to 31 W / (K·m), and the alumina ceramic substrate provided in Comparative Example 2 shows drying and cracking during tape casting; the silicon nitride ceramic of Comparative Example 3 has a relative density of only 95.2%, a hardness of 12.7 GPa, a bending strength of 331 MPa, and a thermal conductivity of 47 W / (K·m). The mechanical properties of the alumina ceramic substrates provided in Examples 1-2 are significantly improved compared to the alumina ceramic substrates provided in Comparative Examples 1 to 2.

[0095] The mechanical properties and thermal properties of the silicon nitride ceramic substrate provided in Example 3 are significantly improved compared to the silicon nitride ceramic substrate provided in Comparative Example 3. Therefore, the ceramic substrate tape casting method based on the light / wet dual curing system provided in the present invention can prepare a ceramic substrate with excellent mechanical properties.

[0096] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A ceramic substrate tape casting method based on a light-moisture dual-curing system, characterized in that: The following steps are involved: S1. Raw material preparation; S2, slurry preparation; S3, adding a cross-linking agent; S4, defoaming treatment; S5, tape casting; S6, initial curing; S7, drying treatment; S8. Sintering treatment.

2. A method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S1 , ceramic powder, solvent and dispersant are weighed in proportion.

3. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S2, the ceramic powder is ball-milled, and the ball-milled ceramic powder is mixed with a dispersant and a solvent to obtain a slurry, and the slurry is stirred.

4. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S3, EBECRYL series acrylic crosslinking agent is added to the uniformly mixed slurry, and ball milling is continued to obtain slurry.

5. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S4, the ball-milled slurry is poured into a vacuum degassing device for degassing.

6. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S5, the slurry is poured into the tape casting slurry tank, and then the scraper height of the tape casting machine is adjusted according to demand.

7. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: After ensuring that the scraper is in the correct position in step S5, the power is turned on, and the slurry in the casting slurry tank is driven forward by the parallel movement of the plastic film belt, and a film layer is formed by the casting scraper.

8. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S6, the heating device is started to initially solidify the cast slurry film, the solidification time is 0.5-2 hours, and the solidification temperature is 20-40°C.

9. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S7, the initially solidified tape-cast green body is cut into a suitable size and then transferred to an oven for drying at a temperature of 30°C-60°C for a drying time of 2-10 hours.

10. The method for tape-casting a ceramic substrate based on a light-moisture dual-curing system according to claim 1, characterized in that: In step S8, the dried green body is taken out from the oven and placed in a sintering furnace for sintering. The sintering method is pressureless sintering or gas pressure sintering. The sintering temperature is 1000-2300°C. The holding time is 2-5h. The sintering atmosphere is any one of air atmosphere, nitrogen atmosphere or argon atmosphere. The heating rate between 0-600°C is 0.1-0.5°C / min, and the heating rate from 600°C to the sintering temperature is 0.5-5°C / min.

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