Method for manufacturing ceramic green sheet and ceramic green sheet manufactured thereby

Abstract

The present invention relates to a method for manufacturing a ceramic green sheet and a ceramic green sheet manufactured thereby, the method comprising the steps of: manufacturing a ceramic slurry by mixing ceramic powder, a binder, and an organic solvent; defoaming the ceramic slurry to adjust viscosity; and forming the defoamed ceramic slurry into a sheet.

Description

Method for manufacturing ceramic green sheets and ceramic green sheets manufactured therefrom

[0001] The present invention relates to a method for manufacturing a ceramic green sheet and a ceramic green sheet manufactured therefrom.

[0002] Electronic devices may include electronic components to which ceramic materials are applied, such as dielectric layers, and ceramic green sheets may be manufactured and applied from slurry containing ceramic materials to such electronic components.

[0003] As electronic devices become smaller, ceramic green sheets are also required to be thinner, but there are problems with high defect rates and low yields when manufacturing thin ceramic green sheets.

[0004] The purpose of the present invention is to provide a method for manufacturing a ceramic green sheet that has a high density and can be formed into a thin film, while improving yield by reducing the rate of defects such as cracks even in a high humidity environment.

[0005] An object of the present invention is to provide a high-density ceramic green sheet by the above method.

[0006] An object of the present invention is to provide a high-density, thin-film ceramic green sheet by the above method.

[0007] The objectives of the present invention are not limited to those mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0008] In one embodiment of the present invention,

[0009] A step of preparing a ceramic slurry by mixing ceramic powder, binder, and organic solvent;

[0010] A step of defoaming the ceramic slurry to adjust the viscosity; and

[0011] A step of forming the above-degassed ceramic slurry into a sheet;

[0012] A method for manufacturing a ceramic green sheet is provided.

[0013] The step of defoaming the above ceramic slurry can be performed under vacuum conditions.

[0014] The above vacuum conditions are 5 × 10 -2 It may be less than mmHg.

[0015] The above ceramic powder may include silicon nitride.

[0016] The above ceramic slurry may further comprise at least one additive selected from the group consisting of a plasticizer, a dispersant, a sintering agent, and combinations thereof.

[0017] In the step of manufacturing the above ceramic slurry, the ceramic slurry can be manufactured with a solid content of 30% by weight to 60% by weight.

[0018] In the step of manufacturing the above ceramic slurry, the viscosity of the ceramic slurry may be 5,000 cP or less at 25°C.

[0019] In the step of defoaming the ceramic slurry, the defoaming can be performed so that the viscosity of the ceramic slurry becomes 1.5 to 3 times before and after defoaming.

[0020] The above-defrosted ceramic slurry can be applied onto a support substrate and then dried to produce a sheet.

[0021] The above-degassed ceramic slurry can be formed into the above-described sheet by tape casting.

[0022] The thickness of the above sheet may be 100 ㎛ or more.

[0023] The method for manufacturing the above ceramic green sheet can be performed under humidity conditions of 10% to 60%.

[0024]

[0025] According to one embodiment of the present invention, a ceramic green sheet manufactured by the method for manufacturing the above ceramic green sheet can be provided.

[0026] The above ceramic green sheet may include silicon nitride.

[0027] The above ceramic green sheet may be formed by tape casting.

[0028] The above ceramic green sheet may have a thickness of 100 ㎛ or more.

[0029] The above ceramic green sheet has a density of 1 g / cm 3 It could be strange.

[0030] The method for manufacturing the ceramic green sheet according to the present invention can manufacture a ceramic green sheet having a high density without causing defects such as cracks even in a high-humidity environment by manufacturing the ceramic green sheet by controlling the viscosity of the ceramic slurry.

[0031] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0032] The aforementioned objectives, features, and advantages are described in detail below, so that those skilled in the art can readily implement the technical concepts of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention will be omitted if they are deemed to unnecessarily obscure the gist of the invention. Hereinafter, preferred embodiments of the present invention will be described in detail.

[0033] In one embodiment of the present invention, a method for producing a ceramic green sheet is provided, comprising: a step of producing a ceramic slurry by mixing a ceramic powder, a binder, and an organic solvent; a step of defoaming the ceramic slurry to control viscosity; and a step of forming the defoamed ceramic slurry into a sheet.

[0034] The method for manufacturing the above ceramic green sheet is capable of manufacturing a ceramic green sheet with high density without causing defects such as cracks even in a high humidity environment by manufacturing the ceramic green sheet by controlling the viscosity of the ceramic slurry.

[0035] Typically, ceramic slurry can be dried to produce ceramic green sheets. Therefore, a drying step is performed during the production of ceramic green sheets, and the drying zone where the drying step is performed has encountered difficulties in controlling the drying rate of the slurry due to the large amount of solvent present. Furthermore, in environments with high humidity, such as summer, the slurry contains a large amount of air bubbles and moisture, which can lead to cracks occurring when moisture escapes at low densities during processes such as tape casting, resulting in the production of defective green sheets.

[0036] The method for manufacturing the above ceramic green sheet can reduce the amount of solvent and moisture by controlling the viscosity by defoaming the ceramic slurry, thereby making it easy to control the drying speed and removing the air bubble layer existing inside the ceramic slurry and ceramic powder particles, thereby manufacturing a ceramic green sheet without cracks and with high density even in a high humidity environment.

[0037]

[0038] The step of defoaming the above ceramic slurry can be performed under vacuum conditions. Specifically, the vacuum conditions are 5 × 10 -2 It may be less than mmHg.

[0039] In one embodiment, the ceramic powder may include silicon nitride as the ceramic material.

[0040] Specifically, the ceramic slurry may further include, in addition to a ceramic powder such as silicon nitride, a binder, and a solvent, at least one additive selected from the group consisting of a plasticizer, a dispersant, a sintering agent, and combinations thereof. Any known additive may be used without limitation depending on the intended use of the ceramic green sheet.

[0041] The above binder can be any compound known to be of an appropriate type depending on the type of the ceramic material, and for example, polyvinyl butyral can be used.

[0042] The above plasticizer can be any compound known to be of an appropriate type depending on the type of the ceramic material, without limitation, and for example, a phthalate plasticizer such as dibutyl phthalate can be used.

[0043] The above solvent may be isopropyl alcohol, toluene, etc., but is not limited thereto, and any known solvent type may be used without limitation.

[0044] The above dispersant is an additive that helps solid particles to be evenly distributed in a liquid medium. For example, BYK-111, a type of ester block copolymer manufactured by BYK Chemie of Germany, may be used, but is not limited thereto, and any known dispersant may be used.

[0045] The above sintering agent is an additive that helps to form a sintered body, and may use MgO, WO3, etc., but is not limited thereto, and any known sintering agent may be used.

[0046] In the step of manufacturing the ceramic slurry, the solid content of the ceramic slurry can be manufactured to be 30 wt% to 60 wt%. By controlling the solid content of the ceramic slurry within the above numerical range, it becomes easy to control the ceramic slurry to have a predetermined density through vacuum degassing, and accordingly, while implementing a high density, cracks do not occur, thereby reducing the defect rate in the manufacture of ceramic green sheets.

[0047] In one embodiment, in the step of manufacturing the ceramic slurry, the viscosity of the ceramic slurry may be manufactured to be 5,000 cP or less, specifically 1,000 cP to 3,000 cP, at 25°C. By preparing the ceramic slurry with a viscosity within the above numerical range and performing vacuum defoaming, it becomes easy to control the ceramic slurry to have a predetermined density through vacuum defoaming, and accordingly, while implementing a high density, cracks do not occur, thereby reducing the defect rate in the manufacture of ceramic green sheets.

[0048] In one embodiment, the viscosity of the ceramic slurry may be defoamed so that it increases by 1.5 to 3 times before and after defoaming. By controlling the viscosity by defoaming within the above numerical range, it becomes easy to control the ceramic slurry to have a predetermined density by vacuum defoaming, and accordingly, a high density may be realized without cracks, thereby reducing the defect rate in the production of ceramic green sheets. For example, when producing a ceramic green sheet for producing a heat-dissipating substrate in which the ceramic powder includes Al2O3 or AlN, a high-density ceramic green sheet may be produced by controlling the viscosity of the ceramic slurry by defoaming as described above.

[0049]

[0050] The step of forming the above-described defoamed ceramic slurry into a sheet may be, specifically, a step of applying the above-described defoamed ceramic slurry onto a support substrate and then drying it to manufacture a sheet.

[0051] In addition, in one embodiment, the defoamed ceramic slurry can be formed into the sheet by tape casting, but tape casting is only one example, and sheet forming is possible by various known methods.

[0052] The ceramic green sheet manufactured by the method for manufacturing the above ceramic green sheet can form a thin film while reducing the defect rate, and furthermore, the ceramic green sheet formed into a thin film has a high density and thus excellent durability, and can realize high thermal conductivity because moisture and air layers are largely eliminated, and is suitable as a component for miniaturized electronic devices.

[0053] In one embodiment, the thickness of the sheet may be 100 μm or more, specifically, 100 μm to 500 μm.

[0054]

[0055] The method for manufacturing the above ceramic green sheet can reduce the defect rate of the obtained ceramic green sheet because the drying process is performed after adjusting the viscosity of the ceramic slurry, and thus the drying process can be performed smoothly even in a high-humidity environment.

[0056] In one embodiment, the method for manufacturing the ceramic green sheet can be performed under humidity conditions of 10% to 60%.

[0057] In one embodiment, the above components, including the ceramic powder, are mixed, and then a ceramic slurry is prepared using a ball mill for 24 hours. The prepared ceramic slurry is then defoamed under reduced pressure for at least 1 hour using a rotary vacuum pump. The defoamed ceramic slurry can be formed into a green sheet through tape casting.

[0058]

[0059] In one embodiment of the present invention, a ceramic green sheet manufactured by a method for manufacturing the ceramic green sheet is provided.

[0060] As described above, the method for manufacturing the ceramic green sheet can prevent crack occurrence and manufacture a high-density ceramic green sheet, so the ceramic green sheet manufactured by the method has excellent quality in terms of crack occurrence and high density.

[0061] The density of the above ceramic green sheet is 1 g / cm 3 Above, specifically 1 g / cm 3 3 g / cm 3 It could be.

[0062] In one embodiment, the ceramic green sheet may include silicon nitride, and is manufactured from the ceramic slurry described in the method for manufacturing the ceramic green sheet, so that the detailed description thereof may be applied identically except for changes in the process, such as the solvent being volatilized by drying.

[0063] For example, the method of forming the ceramic green sheet from the ceramic slurry may be by tape casting.

[0064] As described above, the ceramic green sheet can be manufactured into a high-density thin film.

[0065] The thickness of the ceramic green sheet according to one embodiment of the present invention may be 100 ㎛ or more, specifically, 100 ㎛ to 500 ㎛.

[0066] The density of the ceramic green sheet according to one embodiment of the present invention is 1 g / cm 3 Above, specifically 1 g / cm 3 3 g / cm 3 It could be.

[0067]

[0068] Hereinafter, examples and comparative examples of the present invention will be described. The following examples are merely exemplary of the present invention, and the present invention is not limited to the examples described below.

[0069]

[0070] (Example)

[0071] Example 1

[0072] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to create a ceramic slurry with a viscosity of 2,800 cP at 25°C. Vacuum degassing was performed for more than an hour, and it was confirmed that the viscosity had changed to 5,300 cP at 25°C. This was then used to form an ultra-thin ceramic green sheet of 180 μm.

[0073]

[0074] Example 2

[0075] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to create a ceramic slurry with a viscosity of 2,400 cP at 25°C. Vacuum degassing was performed for more than 1 hour, and it was confirmed that the viscosity had changed to 5,000 cP at 25°C. This was then used to form an ultra-thin ceramic green sheet of 180 μm.

[0076]

[0077] Example 3

[0078] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to create a ceramic slurry with a viscosity of 1,400 cP at 25°C. Vacuum degassing was performed for more than an hour, and it was confirmed that the viscosity had changed to 2,800 cP at 25°C. This was then used to form an ultra-thin ceramic green sheet of 180 μm.

[0079]

[0080] Comparative Example 1

[0081] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to make a ceramic slurry at 25°C, and then natural defoaming was performed for more than 1 hour. Using the ceramic slurry, which maintained a viscosity of 2,800 cP at 25°C with almost no change in viscosity before and after natural defoaming, an ultra-thin ceramic green sheet of 180 μm was formed.

[0082]

[0083] Comparative Example 2

[0084] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to make a ceramic slurry at 25°C, and then natural defoaming was performed for more than 1 hour. Using the ceramic slurry, which maintained a viscosity of 2,400 cP at 25°C with almost no change in viscosity before and after natural defoaming, an ultra-thin ceramic green sheet of 180 μm was formed.

[0085]

[0086] Comparative Example 3

[0087] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to make a ceramic slurry at 25°C, and then natural defoaming was performed for more than 1 hour. Using the ceramic slurry, which maintained a viscosity of 1,400 cP at 25°C with almost no change in viscosity before and after natural defoaming, an ultra-thin ceramic green sheet of 180 μm was formed.

[0088]

[0089] Comparative Example 4

[0090] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to make a ceramic slurry at 25°C, and then natural defoaming was performed for more than 1 hour. Using the ceramic slurry, which maintained a viscosity of 2,400 cP at 25°C with almost no change in viscosity before and after natural defoaming, an ultra-thin ceramic green sheet of 170 μm was formed.

[0091]

[0092] Comparative Example 5

[0093] Silicon nitride powder was mixed with a binder (polyvinyl butyral, PVB), an organic solvent (isopropyl alcohol), a plasticizer (dibutyl phthalate, DBP), a dispersant (BYK-111, manufactured by BYK Chemie, Germany), and a sintering agent (MgO) to make a ceramic slurry at 25°C, and then natural defoaming was performed for more than 1 hour. Using the ceramic slurry, which maintained a viscosity of 2,550 cP at 25°C with almost no change in viscosity before and after natural defoaming, an ultra-thin ceramic green sheet of 175 μm was formed.

[0094]

[0095] The viscosity (25°C) of the ceramic slurry after defoaming in Example 1-3 and Comparative Example 1-5, the thickness of the manufactured ceramic green sheet, the humidity conditions, and the yield are shown in Table 1 below.

[0096]

[0097] Viscosity (cP) (25℃) Thickness (㎛) Humidity (%) Yield (%) Example 15, 300 180 5895 Example 25, 000 175 4595 Example 32, 800 152 5595 Comparative Example 12, 800 180 580 143 5895 Comparative Example 22, 400 180 650 145 6595 Comparative Example 31, 400 180 550 140 5595 Comparative Example 42, 400 170 1095 170 4030 Comparative Example 52, 550 175 3520

[0098] In Table 1, when comparing the yields in Example 1-3 and Comparative Example 1-5, it can be seen that Example 1-3 has a high yield of 95% even when the humidity is 40% or higher. However, in Comparative Example 1-5, it can be seen that the yield for a thickness of 180 ㎛ is low at 0% when the humidity is 40% or higher. From this, it can be confirmed that by controlling the viscosity through defoaming in Example 1-3, air bubbles and moisture inside the slurry are removed, thereby preventing cracks from occurring even in a high-humidity environment, thereby reducing the defect rate and manufacturing a green sheet with a high yield.

[0099]

[0100] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the exemplary embodiments disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical spirit of the invention. Furthermore, even if the operational effects of the configurations of the invention have not been explicitly described and explained while describing the exemplary embodiments of the invention, it is also to be understood that the effects predictable by the configurations should be acknowledged.

Claims

1. A step of preparing a ceramic slurry by mixing ceramic powder, binder, and organic solvent; A step of defoaming the ceramic slurry to adjust the viscosity; and A step of forming the above-degassed ceramic slurry into a sheet; Method for manufacturing ceramic green sheets.

2. In paragraph 1, The step of defoaming the above ceramic slurry is performed under vacuum conditions. Method for manufacturing ceramic green sheets.

3. In paragraph 2, The above vacuum conditions are 5 × 10 -2 mmHg or less Method for manufacturing ceramic green sheets.

4. In paragraph 1, The above ceramic powder contains silicon nitride. Method for manufacturing ceramic green sheets.

5. In paragraph 1, The above ceramic slurry further comprises at least one additive selected from the group consisting of a plasticizer, a dispersant, a sintering agent and a combination thereof. Method for manufacturing ceramic green sheets.

6. In paragraph 1, In the step of manufacturing the above ceramic slurry, the solid content of the above ceramic slurry is manufactured to be 30% to 60% by weight. Method for manufacturing ceramic green sheets.

7. In paragraph 1, In the step of manufacturing the above ceramic slurry, the viscosity of the ceramic slurry is 5,000 cP or less at 25°C. Method for manufacturing ceramic green sheets.

8. In paragraph 1, In the step of defoaming the ceramic slurry, the viscosity of the ceramic slurry is defoamed so that it becomes 1.5 to 3 times before and after defoaming. Method for manufacturing ceramic green sheets.

9. In paragraph 1, The above-mentioned defoamed ceramic slurry is applied onto a support substrate and then dried to produce a sheet. Method for manufacturing ceramic green sheets.

10. In paragraph 1, The above-defrosted ceramic slurry is formed into the above-described sheet by tape casting. Method for manufacturing ceramic green sheets.

11. In paragraph 1, The thickness of the above sheet is 100 ㎛ or more Method for manufacturing ceramic green sheets.

12. In paragraph 1, Performed under 10% to 60% humidity conditions Method for manufacturing ceramic green sheets.

13. Ceramic green sheet manufactured by the method according to paragraph 1.

14. In paragraph 13, The above ceramic green sheet contains silicon nitride. Ceramic green sheet.

15. In paragraph 13, molded by tape casting Ceramic green sheet.

16. In paragraph 13, Thickness of 100 ㎛ or more Ceramic green sheet.

17. In paragraph 13, Density is 1 g / cm 3 Lee Sang-in Ceramic green sheet.