Planarization of ceramic substrates using porous materials

1. Field of Invention

This invention mainly provides a concept of using porous materials on ceramic substrate planarization. This planarized substrate can be utilized in the fields of electronic information communication, opto-electronics and display.

2. Description of the Prior Art

It is an important postulation for having a planar surface for the thin-film processes. The high cost is due to two main aspects. The first aspect is due to the high substrate-polishing cost based on either silicon wafer or glass manufacture factory. The second aspect is the high fabrication cost on the flattening technology as a key technology to produce metallized module IC.

At present, some common smoothing techniques include mechanical polishing, chemical mechanical polishing, chemical etching, high temperature reflow through borophosphosilicate, and spin coating. Thin film's roughness and adherence are often limited after surface treatment at which may additionally complicate the processing and increase the cost. The prior arts are shown as following:

Conclusively, the main purpose of this invention can solve the above-mentioned defects (film crack, delamination, etc.). In order to overcome these problems, this invention provides a concept of using porous materials on ceramic substrate planarization, wherein the nanostructure layer provides the required surface smoothness upon the ceramic substrates and enhances the adhesion between substrate and subsequent thin-film layers.

This invention can tremendously reduce the production cost due to its simple production process.

In order to achieve the said objectives, the invention provides a method of using porous materials on ceramic substrate planarization. This invention sustains a surface flattening method by employing the participation of porous materials such as zeolites, zeolite-like, mesoporous and mesoporous composites. Meanwhile, this invention results in good affinity for the electrical and dielectric properties, for instance, thermal conductivity, electrical insulation, dielectric and other required properties for integrated components. Due to a good polarization obtained, this invention permits furthermore an intensive binding between thin films and electronic materials.

FIG. 1 : Schematic drawing of the architecture of the smoothing technology indicated in the invention description.

FIG. 2 : X-ray photograph of example 1.

FIG. 3 : SEM photograph of example 1.

FIG. 4 : Flatten result on the ceramic substrates surface.

FIG. 5 a : Adhesive test of example after deposition of an Al film having a thickness of 6.5 μm and patternization by photolithography.

FIG. 5 b : Optical picture of the flatten sample on which an Al film having a thickness of 6.5 μm has been deposited.

FIG. 6 a : A current-voltage relationship of the diode which made from the flatten sample (first example).

FIG. 6 b : RLCD integrated circuit made from the flatten sample(first example).

This invention mainly provides a method of using porous materials on ceramic substrate planarization. The concept of this invention includes at least a layer of ceramic substrate 30 , a buffer layer 20 , and nanostructured layer 10 . As shown in FIG. 1, it is a schematic drawing of the architecture of the smoothing technology indicated in the invention description. First this invention provides a ceramic substrate 30 , then a buffer layer 20 forms on the ceramic substrate 30 and a nanostructure layer 10 forms upon the buffer layer 20 .

The ceramic substrate 30 provides the structure stress and surface-mount capability. The buffer layer 20 provides the adhesion between the substrate layer 30 and nanostructured layer 10 . The buffer layer 20 can be chosen from one of or some of the following materials: glaze, glass, ceramic, mesoporous and mesoporous composites. The nanostructure layer 10 is formed by the self repetitively assembled mechanism in order to offer the required surface smoothness of the ceramic substrates for performing the thin-film process techniques, adhesion for metallization and electronic materials, thermal conductivity, electrical insulation, dielectric and other electric material required functions. The nanostructure layer 10 is chosen from one of or some of the following materials: zeolites, zeolite-like, mesoporous and mesoporous composites. Moreover, the buffer layer 20 and nanostructure layer 10 can be either the same layer or multilayer.

The concept of the this invention utilizes the nanostructure layer 10 to provide required thermal conductivity, electrical insulation, adhesion, dielectric and other electric material required functions for the substrate that comprises LTCC, chip-carrier, passive device, active device, light emitting device, optical passive device and optical active device and their complexes.

The properties and the advantages of this invention are shown in the following example, which can be one of applications.

Flatness Test

The formation of sample as represented in FIG. 2, where substrate 30 was aluminum oxide, buffer layer 20 was glaze, and nanostructure layer 10 was zeolite-like material. X-ray analysis of crystal structure is shown in FIG. 3, the peak signal informs the self-assembly zeolite-like structure. The SEM picture given in FIG. 4 shows the profile of Al 2 O 3 substrate of 30 , glaze buffer layer 20 and nanostructure zeolite-like layer 10 . The flatness measurement shown in FIG. 5 shows flatness in angstrom dimension.

Adhesion Test

As shown in FIG. 6 a , it is the adhesive test of example 1 after deposited 6.5 μm thickness layers of Al film and patternized by photolithography. FIG. 5 b is the optical picture of flatten sample deposited 6.5 μm thickness layers of Al film for adhesion test. A 6.5 μm thickness layer of Al film deposited on flatten sample and patternized by photolithography, this picture indicates an excellent adhesion between substrate and Al layer. It is fully agreement to the α-step profiling measurement shown in FIG. 5 a.

Practicable Test

As shown in FIG. 6 a , it is the current-voltage relationship of the diode made from the flatten sample (first example), and in FIG. 6 b , it is the RLCD integrated circuit made from the flatten sample (first example). Hence, these are evident examples that proof this invention is practicable.

It should be apparent to those skilled in the art that the above description is only illustrative of specific embodiments and examples of the invention. The invention should therefore cover various modifications and variations made to the herein-described structure and operations of the invention, provided they fall within the scope of the invention as defined in the following appended claims.