**3. Fine conductive patterning process**

The fine conductive pattern is desired for miniature electronic elements, a packaging ceramic, an interposer, and the furthermore. In the conventional process for forming the fine pattern, a vacuum process is used. However, this process has the issue that required the high fabrication cost and the extensive system. Therefore, the researcher focuses on the printed electronics. The screen printing process has been used for the ceramic electronic components already, and then, the gravure printing and ink-jet printing are introduced. However, it is difficult to realize the fine pattern and the low fabrication cost simultaneously only the printing technology. Therefore, the references the line widths of the fine pattern in the production and in the research field are 50 and 10–30 μm, respectively.

The proposed photoresist process can form the fine pattern by the simplified process that combined the photolithography process with the printing process. The fabrication process was base photoresist process (**Figure 1**), and a specific process is shown in **Figure 2**. For the fine pattern, liquid type photoresist was coated on a glass substrate. The designed line and

**2.1. Concept and base process of photoresist process**

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patterned different material into the green sheet.

production process of the miniature ceramic components.

**3. Fine conductive patterning process**

research field are 50 and 10–30 μm, respectively.

The proposed process uses the photoresist pattern. The first step, the photoresist is exposed for forming the designed pattern. The sacrifice patterns of the photoresist are obtained after development. In a case of a ceramic sheet with a through-pattern, the green sheet of the base material is formed using the doctor blade. At the time, the gap between the blade and the surface of the resist film is adjusted to zero. Therefore, the slurry fills surrounding the sacrifice pattern. Then, the specimens are dried. After the sacrifice pattern is dissolved, the green sheet of the base material with the through-pattern is achieved. To form the pattern, the through-pattern is exposed and developed on the photoresist. The ceramic slurry or conductive paste is filled into the through-pattern, after the dissolving process, the ceramic pattern, or conductive pattern is achieved. **Figure 1** shows the schematic illustration of the process for producing the

A liquid type photoresist and a film type photoresist are chosen for the achieved pattern. For a fine pattern, the liquid type photoresist is used. And then, the film type photoresist is employed for forming the sheet pattern because it realizes the uniform thickness. In this chapter, the different pattern process uses the film type photoresist, and the fine conductive pattern uses the liquid type. The advantage of this process is that it uses a photolithography process. The photolithography process is used for the IC or microelectromechanical systems (MEMS) sensor fabrication process. Both products have a fine conductive pattern and miniature structure. Therefore, the proposed process that uses the photolithography process is suitable to miniaturize. Moreover, the flexible pattern designing is possible. In addition, the sacrifice resist pattern forms the through-hole pattern. On the other hand, it is a mask pattern that covered on the ceramic sheet. The photoresist mask pattern holds the filling paste as the ceramic slurry or conductive paste. It is possible to form the high-aspect-ratio pattern. These characteristics are used for the

The fine conductive pattern is desired for miniature electronic elements, a packaging ceramic, an interposer, and the furthermore. In the conventional process for forming the fine pattern, a vacuum process is used. However, this process has the issue that required the high fabrication cost and the extensive system. Therefore, the researcher focuses on the printed electronics. The screen printing process has been used for the ceramic electronic components already, and then, the gravure printing and ink-jet printing are introduced. However, it is difficult to realize the fine pattern and the low fabrication cost simultaneously only the printing technology. Therefore, the references the line widths of the fine pattern in the production and in the

The proposed photoresist process can form the fine pattern by the simplified process that combined the photolithography process with the printing process. The fabrication process was base photoresist process (**Figure 1**), and a specific process is shown in **Figure 2**. For the fine pattern, liquid type photoresist was coated on a glass substrate. The designed line and

**Figure 2.** Fabrication process of fine conductive pattern. (1) glass substrate is coated with liquid type photoresist. (2) exposed and developed. (3) filled paste and dissolved.

space were 10 μm, respectively. The conductive paste that combined with microparticle metal powder (under 0.1 μm) was used. The filled conductive paste was dried on the hot plate keeping 60°. After that, the photoresist pattern was removed by remover.

The low viscosity paste was required for form the fine pattern, the photoresist pattern held the paste at the drying process. It can form the high-aspect-ratio pattern. The developed photoresist pattern and the conductive pattern on the glass substrate are shown in **Figures 3** and **4**.

**Figure 3.** Patterned liquid type photoresist for fine conductive pattern.

**Figure 4.** Formed fine conductive pattern.

These images were observed by the confocal microscope. The filling process was metal blade method. A pore and a crack were not shown on the surface of the conductive pattern, and the paste was filled completely. The width and height of the pattern were 10.3 and 1.85°μm, respectively. The fine and high-aspect-ratio pattern was achieved. However, a thin-film conductor around the line pattern was observed. It is a residual conductive paste that was coated on the resist pattern. When the conductive paste was filled, the gap between the metal blade and the resist pattern was occurred. And then, the dried paste on the resist remained with the side of the pattern. The schematic illustration of the mechanism of the residual pattern is shown in **Figure 5**. 3D measuring result of the conductive pattern using same fabrication process is shown in **Figure 6**. The side of the conductor formed the thin pattern. It is solved by adjusting the gap between the blade and the resist surface.

**4. Different material patterning process**

**Figure 6.** 3D measuring result of conductive pattern by photoresist process.

**Figure 7.** Schematic illustration of photoresist process for different material pattern.

The different material patterning process can form some material patterns in one ceramic sheet without bump structure. The ceramic material is often used for the module circuit [11]. When the different ceramic materials are used, the module circuit with some electronic characteristics is realized. When the ceramic material and the conductive material are used, the conductive circuit pattern with high-aspect-ratio pattern and the flat surface pattern. **Figure 7** shows the patterning

Powder Process with Photoresist for Ceramic Electronic Components

http://dx.doi.org/10.5772/intechopen.76881

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**Figure 5.** Schematic illustration of mechanism of residual pattern.

**Figure 6.** 3D measuring result of conductive pattern by photoresist process.
