TW201316461A - Method for fabricating a ceramic substrate - Google Patents

Abstract

A method for fabricating a ceramic substrate is disclosed and includes the follow steps. First, a ceramic substrate is immersed into a chemical solution and the chemical solution would etch a surface of the ceramic substrate. The immersing time of the ceramic substrate is about two minutes and the operating temperature could be the room temperature. Via these arrangements, the surface of the ceramic substrate after etched will have a roughness that can make a circuit structure more firmly attach on the surface.

Description

Ceramic substrate processing method

The invention relates to a processing method of a substrate, in particular to a processing method applied to a ceramic substrate.

With the development of miniaturization and light weight of electronic components, the technology of using an aluminum plate as a substrate has been gradually replaced by a light-weight ceramic substrate having a high degree of insulation, excellent chemical stability, and high hardness. The characteristics such as high temperature resistance make the ceramic substrate have better substrate suitability than the aluminum plate.

The methods commonly used for processing on ceramic substrates are nothing more than: hot pressing or high temperature co-firing. However, if a metal material is formed on a ceramic substrate by thermocompression bonding, if the metal material is too thick, the joint surface is oxidized and the overall thermal resistance is increased. If the metal material is too thin, the metal material is made thin. Easy to peel or crack, reducing overall yield. Therefore, the way of thermocompression is often limited to technical problems.

On the other hand, the method of co-firing at a high temperature is limited by the use of a metal material having a high melting point, such as a metal such as tungsten or manganese, which not only improves the overall circuit resistance, but also has poor performance of the finished product. In addition, the use of high temperature co-firing improves the cost of the overall process. Although the ceramic substrate has been processed in a low-temperature co-firing process in recent years, the steps are still complicated, and the cost cannot be effectively reduced.

In view of the above, the present invention provides a method for processing a ceramic substrate which can improve the above disadvantages, so as to solve the problems to be solved in the industry.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of processing a ceramic substrate which can easily attach a surface of a processed ceramic substrate to a circuit structure.

It is still another object of the present invention to provide a method of processing a lower cost ceramic substrate.

In order to achieve the above object, the processing method of the present invention comprises at least the steps of first immersing a ceramic substrate in a chemical solution such that a surface of the ceramic substrate is etched by the chemical solution, and the chemical solution can be a complex acid. When the chemical solution etches the surface of the ceramic substrate to the extent that it can be attached or fabricated as a subsequent circuit structure, the ceramic substrate is taken out and the chemical solution remaining on the ceramic substrate is removed. The time during which the ceramic substrate is immersed in the chemical solution is substantially two minutes, and the operating temperature is room temperature.

The above objects, technical features and advantages will be apparent to those skilled in the art, and the following detailed description of the preferred embodiments of the invention.

The present invention is a method for processing a ceramic substrate, wherein FIG. 1 shows a first preferred embodiment of the processing method of the present invention, and is also a basic structure of the processing method of the present invention, and FIG. 2, FIG. 3, and FIG. The figure and Figure 7 show other possible implementations based on the basic architecture shown in Figure 1.

Referring to FIG. 1 , the method for processing the ceramic substrate may include four steps. In step S1, a ceramic substrate is immersed in a chemical solution, so that a surface of the ceramic substrate chemically reacts with the chemical solution and is The chemical solution is etched. In this embodiment, the chemical solution can be a concentration of one hundred percent complex acid.

When the surface of the ceramic substrate is etched to the extent that it can be attached or fabricated as a subsequent circuit structure, the process proceeds to step S2, the ceramic substrate is taken out and the chemical solution remaining on the surface is washed. In the embodiment, the preferred ceramic substrate is immersed in the chemical solution for a period of two minutes, and the allowable correction time is plus or minus ten seconds, and the overall operating temperature is room temperature (for example, about 24 or 25 degrees). ).

The surface of the etched ceramic substrate may have a preferred roughness such that the circuit structure formed on the surface thereafter can be more firmly attached to the surface.

In order to make the subsequent circuit structure more firmly attached to the surface of the ceramic substrate (at least when heated to 400 degrees, the circuit structure still does not peel off), step S3 is to activate the surface of the ceramic substrate, the way of activation A catalyst containing palladium metal can be used to activate the surface of the ceramic substrate and increase the surface area to which the subsequent circuit substrate can be attached. Finally, step S4 forms a circuit structure on the surface of the activated ceramic substrate.

It should be noted that in order to streamline the process and make the general technical knowledge easy to understand the core technical content of the present invention, the residual solvent is removed between steps or as a basic step to improve the overall yield, such as washing, polishing, drying, etc. Etc., and are not described in this specification.

Next, please refer to FIG. 2, which is a flowchart of a second preferred embodiment of the method for processing a ceramic substrate of the present invention, wherein steps S1 to S3 are similar to the foregoing, and thus are not described again. The circuit structure forming step (S4) of the processing method of the second embodiment is performed by using a positive film process.

In detail, in the processing method using the positive film process, the step S4 of forming a circuit structure may further include steps S411 to 415. Step S411 is to form a copper layer on the surface of the activated ceramic substrate. The copper layer may further include a first copper layer and a second copper layer. First, a first copper layer is formed on the surface of the activated ceramic substrate by chemical means (for example, electroless plating), followed by electroplating. The method forms a second copper layer on the first copper layer.

Next, in step S412, a tin layer is formed on the copper layer, and then a patterned photoresist layer is formed on the tin layer (step S413). The method for forming the patterned photoresist layer may be screen printing, a photomask or It is a method of wet film coating. After the exposure and development, the process proceeds to step S414 to remove the copper layer and the tin layer not covered by the patterned photoresist layer.

Referring to FIG. 4, it is a schematic structural view of a ceramic substrate produced by the processing method of the second embodiment or the third embodiment. The circuit structure 2 includes the first copper layer 21, the second copper layer 22 and the tin layer 23 formed by the steps S411 and S412, respectively, wherein the tin layer 23 further protects and avoids the first copper layer 21 and The function of the oxidation of the two copper layers 22 is.

Next, please refer to FIG. 3, which is a flow chart of a third preferred embodiment of the method for processing a ceramic substrate of the present invention. Compared with the processing method shown in FIG. 2, the circuit structure forming step (S4) of the processing method of the third embodiment is performed by using a negative chip process, and the circuit structure generated by using the negative chip process is also the same. 4 is drawn.

In detail, the circuit structure forming step (S4) of the third embodiment includes: step 421, forming a first copper layer on the surface of the activated ceramic substrate. Next, in step 422, a patterned photoresist layer is further formed on the first copper layer. Then, a second copper layer and a tin layer are sequentially formed on the first copper layer not covered by the patterned photoresist layer (step 423). The patterned photoresist layer formed in step 422 is removed in step 424. The first copper layer not covered by the second copper layer and the tin layer is then removed. The method of construction between the various layers has been described above, so it will not be described again.

Next, please refer to FIG. 5, which is a flow chart of a fourth preferred embodiment of the method for processing a ceramic substrate of the present invention. The processing method of the fourth embodiment is different from the foregoing several methods in that step S4 does not require step S3 as shown in FIGS. 1 to 3 to activate the surface of the ceramic substrate before forming a circuit structure in the ceramic substrate.

In detail, after the ceramic substrate is cleaned, a silver paste is applied directly to the surface of the ceramic substrate (step S431). Next, in step S432, the silver paste is cured by sintering or the like, and finally a tin layer is chemically formed on the silver paste (step S433). Please refer to FIG. 6 together for a schematic structural view of a ceramic substrate produced by the processing method of the fourth embodiment. The circuit structure 2 on the ceramic substrate 1 includes a silver paste 24 and a tin layer 23.

Please refer to FIG. 7 , which is a flow chart of a fifth preferred embodiment of the method for processing a ceramic substrate of the present invention. The processing method of the fifth comparative embodiment is similar to that of the fourth embodiment, and it is not necessary to first activate the surface on the ceramic substrate, but the processing method of the fifth preferred embodiment uses a sintered molybdenum-manganese alloy to fabricate the circuit structure.

In detail, after the ceramic substrate is cleaned (S2), a molybdenum-manganese alloy layer is directly screen-printed on the surface in step S441, and the molybdenum-manganese alloy layer is first sintered after screen printing. Next, in step S442, a copper layer is formed on the molybdenum-manganese alloy layer by electroplating. In step S443, a tin layer may be formed on the copper layer by chemical or electroplating. And in step S444, a patterned photoresist layer is formed on the tin layer. After the exposure and development, in step S445, the copper layer, the tin layer and the molybdenum-manganese alloy layer not covered by the patterned photoresist layer are removed. Finally, the patterned photoresist layer is removed.

Please refer to FIG. 8 , which is a schematic structural view of a ceramic substrate produced by the processing method of the fifth embodiment. The circuit structure 2 on the ceramic substrate 1 sequentially includes a molybdenum-manganese alloy layer 25, a copper layer 21, and a tin layer 23.

In summary, the present invention is a processing method on a ceramic substrate, which immerses the ceramic substrate in a chemical solution to obtain a surface state (surface roughness) suitable for the circuit structure to be firmly formed thereon. The ceramic substrate was taken out and washed. The invention can achieve the purpose of forming a circuit structure on a ceramic substrate in a lesser step.

The embodiments described above are only intended to illustrate the embodiments of the present invention, and to explain the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any changes or equivalents that can be easily made by those skilled in the art are within the scope of the invention. The scope of the invention should be determined by the scope of the claims.

1. . . Ceramic substrate

2. . . Circuit configuration

twenty one. . . First copper layer / copper layer

twenty two. . . Second copper layer

twenty three. . . Tin layer

twenty four. . . Silver paste

25. . . Molybdenum manganese alloy layer

S1 to S4. . . Step process

1 is a flow chart of a first preferred embodiment of a method of processing a ceramic substrate of the present invention;

2 is a flow chart of a second preferred embodiment of a method for processing a ceramic substrate of the present invention;

3 is a flow chart of a third preferred embodiment of a method for processing a ceramic substrate of the present invention;

Figure 4 is a schematic view showing the structure of a ceramic substrate produced by the processing method shown in Fig. 2 or 3;

Figure 5 is a flow chart showing a fourth preferred embodiment of the method for processing a ceramic substrate of the present invention;

Figure 6 is a schematic view showing the structure of a ceramic substrate produced by the processing method shown in Figure 5;

Figure 7 is a flow chart showing a fifth preferred embodiment of the method for processing a ceramic substrate of the present invention;

Fig. 8 is a schematic view showing the structure of a ceramic substrate produced by the processing method shown in Fig. 7.

S1 to S4. . . Step process

Claims (11)

A method for processing a ceramic substrate, comprising:
Soaking a ceramic substrate in a chemical solution such that a surface of the ceramic substrate is etched by the chemical solution; and removing the ceramic substrate, and removing the chemical solution remaining on the ceramic substrate;
The time during which the ceramic substrate is immersed in the chemical solution is substantially two minutes, and the operating temperature is room temperature. The method of processing a ceramic substrate according to claim 1, wherein the chemical solution is a complex acid. The method for processing a ceramic substrate according to claim 1, further comprising: activating the surface of the ceramic substrate by a catalyst. The method of processing a ceramic substrate according to claim 3, wherein the catalyst comprises a palladium metal. The method of processing a ceramic substrate according to claim 3, further comprising: forming a circuit structure on the surface of the activated ceramic substrate. The method of processing a ceramic substrate according to claim 5, wherein the step of forming the circuit structure further comprises:
Forming a copper layer on the surface of the activated ceramic substrate;
Forming a tin layer on the copper layer;
Forming a patterned photoresist layer on the tin layer;
Removing the copper layer and the tin layer not covered by the patterned photoresist layer; and removing the patterned photoresist layer. The method of processing a ceramic substrate according to claim 6, wherein the step of forming the copper layer further comprises:
Forming a first copper layer on the surface of the activated ceramic substrate by chemical means; and forming a second copper layer on the first copper layer by electroplating. The method of processing a ceramic substrate according to claim 5, wherein the step of forming the circuit structure further comprises:
Forming a first copper layer on the surface of the activated ceramic substrate;
Forming a patterned photoresist layer on the first copper layer;
Forming a second copper layer and a tin layer on the first copper layer not covered by the patterned photoresist layer;
Removing the patterned photoresist layer; and removing the first copper layer not covered by the second copper layer and the tin layer. The method for processing a ceramic substrate according to claim 1, further comprising: forming a circuit structure on the surface of the ceramic substrate. The method of processing a ceramic substrate according to claim 9, wherein the step of forming the circuit structure further comprises:
Coating a silver paste on the surface of the ceramic substrate;
The silver paste is cured; and a tin layer is formed on the cured silver paste. The method of processing a ceramic substrate according to claim 9, wherein the step of forming the circuit structure further comprises:
Forming a molybdenum-manganese alloy layer on the surface of the ceramic substrate;
Forming a copper layer on the molybdenum-manganese alloy layer;
Forming a tin layer on the copper layer;
Forming a patterned photoresist layer on the tin layer;
Removing the copper layer, the tin layer, and the molybdenum-manganese alloy layer that are not covered by the patterned photoresist layer; and removing the patterned photoresist layer.