JPH0350149A - Production of ceramic green sheet - Google Patents

Abstract

PURPOSE:To obtain the above sheet which has a flat surface and is improved in surface roughness after calcination by specifying a solvent at the time of using a slurry consisting of glass powder, powder of alumina, etc., plasticizers such as DOP and toluene as a solvent. CONSTITUTION:The slurry consisting, by weight %, of 40 to 60% glass powder, 60 to 40% ceramic powder of alumina or mullite powder, IBMA(isobutyl methacrylate) or DOP(dioctyl phthalate) as a binder and isobutyl acetate as the solvent is used. The toluene used heretofore is substd. with the isobutyl acetate in such a manner, by which the surface of a green sheet is additionally flattened. The surface roughness after calcination is correspondingly improved and there is no need for polishing the green sheet even in the case of using the sheet as a white board; for example, the formation of copper-polyimide wirings with which fine wiring is possible is facilitated in the case of using the sheet as a multilayered substrate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing ceramic green sheets used, for example, in ceramic multilayer wiring circuit boards, and particularly relates to a method for using ceramic green sheets such as Au, ^g, Ag-Pd, Cu, etc. The present invention relates to a method of manufacturing a green sheet for a low temperature fired substrate using a low melting point metal as a conductor.

[Prior Art] Conventionally, as shown in Japanese Patent Application Laid-Open No. 57-206088, ceramic green sheets are produced by adding a dispersant and a solvent to alumina powder as the main component and glass powder as a sintering aid. In addition, after pulverizing and mixing with a ball mill for 24 hours, a binder and a plasticizer were added and the mixture was heated again for 24 hours.
Ball mill the mixture to make a slurry, then defoamer to adjust the viscosity of the slurry, pour this onto a Mylar sheet coated with silicone, and adjust the thickness of the green sheet using the gap between the doctor blade and the above sheet. It will be done. The composition of the ceramic green sheet used for the low-temperature fired substrate is 40-60% by weight of alumina powder, 60-40% by weight of glass powder, and methacrylic-based IBMA (isobutyl methacrylate) as a binder.
, DBP (dibutyl methacrylate) as a plasticizer,
Toluene is used as a solvent.

In ceramic multilayer wiring circuit boards, through holes are formed in the green sheet created by the above method to ensure interlayer conduction, and conductive paste is filled into the through holes by screen printing, and the wiring pattern is also formed by screen printing. do. Then, a desired number of green sheets were laminated and integrated by heat-pressing (1 cm2 at 120° C., 150° C.), and fired at about 900° C. to form a ceramic multilayer wiring board.

[Problems to be Solved by the Invention] Conventional ceramic multilayer circuit boards are produced by the method described above, so it is necessary for the green sheet to have uniform thickness and small surface roughness. In the composition for low-temperature firing substrates, toluene is used as a solvent, so the green sheet dries quickly, the surface roughness tends to increase, pinholes are more likely to form, and the toxicity is similar to that of benzene when handling. There were issues such as being unfavorable from a rice cake safety standpoint.

This invention was made in order to solve these problems, and the surface becomes flatter, the surface roughness after firing is improved, and even when used as a white board, there is no need to polish it, making it more economical. An object of the present invention is to obtain a method for manufacturing a ceramic green sheet that can be used, for example, as a multilayer substrate.

[Means for Solving the Problems] The method for producing a ceramic green sheet of the present invention includes 40 to 60% by weight of glass powder, 60 to 60% by weight of ceramic powder of at least one of alumina powder and mullite powder.
40% by weight, IBMA (isobutyl methacrylate) as a binder, at least one of DBP (dibutyl phthalate) and DOP (dioctyl phthalate) as a plasticizer, and isobutyl acetate as a solvent.

[Effect] By replacing toluene, which was conventionally used as a solvent, with isobutyl acetate, the surface roughness of the green sheet is improved, and the surface roughness of the ceramic multilayer circuit board after firing is also improved. It becomes easy to form copper-polyimide wiring with a thickness of several μm, which allows fine wiring by plate making.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 250 g of alumina powder (trade name: Meijin CLM-27, manufactured by Sumitomo Aluminum), glass powder (SiO, AIO, Ca
O, BO, BaO.

Glass powder composed of MgO, ZrO) at 250
g, and 250 g of isobutyl acetate as a solvent were added thereto, and the mixture was ground in a ball mill for 24 hours. After that, 135 g of methacrylic II3MA was added as a binder, and 15 g of DBP was added as a plasticizer. In addition, the ball mill was again used for 24 hours to mix and create a slurry.Next, this slurry was defoamed to a viscosity that can be molded into a sheet (the amount of solvent removed was 120cc).
Shite.

Thickness 0.20~0.25m by doctor blade method
A ceramic green sheet according to an embodiment of the present invention was obtained, and its surface roughness is shown in Table 1.

Comparative Examples 1 to 3 When producing ceramic green sheets, it was investigated what kind of difference occurred in the surface roughness of the green sheets depending on the difference in solvent. That is, ceramic green sheets were prepared in the same manner as in Example 1 except that toluene (Comparative Example 1), methyl ethyl ketone (Comparative Example 2), and Cellsolve Acetate (Comparative Example 3) were used as solvents. The solvents used here are shown in Table 1.
The conditions for the solvent are to completely dissolve the binder material (IBMA) and to have a boiling point of 8 due to sheet forming problems.
The temperature must be between 0°C and 150°C.

Table 1 From the results of Example 1 and Comparative Examples 1 to 3 above, it can be seen that the green sheet using isobutyl #acid as a solvent has a small surface roughness, and from a process perspective, when Cellsolve Acetate is used Due to its high boiling point, it takes time to defoam, and the sheet does not dry easily during sheet molding.From a handling standpoint, toluene and methyl ethyl ketone are designated as deleterious substances, so they cannot be used in production. Table 2 shows the surface roughness of the sintered bodies obtained by firing the green sheets of Example 1 and Comparative Examples 1 to 3 in the atmosphere at 900°C for 1 hour.
It can be seen that the surface roughness of the green sheet also affects the sintered body.

Table 2 Example 2 Next, a slurry was prepared in the same manner as in Example 1 except that mullite powder was used instead of the alumina powder in Example 1, and green sheet molding was performed. The surface roughness of the slurry is shown in Table 3. show.

Comparative Examples 4 to 6 Ceramic green sheets were prepared in the same manner as in Comparative Examples 1 to 3, except that mullite powder was used instead of the alumina powder in Comparative Examples 1 to 3, and the surface roughness was measured as shown in Table 3.
Shown below.

Table 3 From the results of Example 2 and Comparative Examples 4 to 6, it can be seen that the case where #acid isobutyl is used is the smallest compared to the cases where other solvents, toluene, methyl ethyl ketone, and cellosolve acetate are used.

Further, in the above embodiment, a case was shown in which DBP (dibutyl phthalate) was used as the lubricating agent, but DOP (dioctyl phthalate) may also be used.

Note that if the mixed amounts of glass powder and ceramic powder are outside the above range, the properties of the green sheet will deteriorate.

[Effects of the Invention] As explained above, the present invention has a glass powder of 40 to 60
60-40% by weight of at least one ceramic powder selected from alumina powder and mullite powder, IBMA (isobutyl methacrylate) as a binder,
DBP (dibutyl phthalate) and D as plasticizers
By using a slurry composed of at least one type of OP (dioctyl phthalate) and #acid isobutyl as a solvent, the surface becomes flatter and the surface roughness after firing is improved, even when used as a white board. There is no need for polishing, making it more economical. For example, multi-J
When used as a W substrate, it is possible to obtain a method for manufacturing a ceramic green sheet that facilitates the formation of copper-polyimide wiring that allows fine wiring.

Claims (1)

[Claims] 40 to 60% by weight of glass powder, at least one ceramic powder selected from alumina powder and mullite powder 6
Ceramic green sheet using a slurry composed of 0 to 40% by weight, IBMA (isobutyl methacrylate) as a binder, at least one of DBP (dibutyl phthalate) and DOP (dioctyl phthalate) as a plasticizer, and isobutyl acetate as a solvent. manufacturing method.