Method of forming a multilayer structure

Abstract

Method of forming a multilayer structure by electroetching or electroplating on a substrate. A seed layer is arranged on the substrate and a master electrode is applied thereto. The master electrode has a pattern layer forming multiple electrochemical cells with the substrate. A voltage is applied for etching the seed layer or applying a plating material to the seed layer. A dielectric material (9) is arranged between the structures (8) thus formed. The dielectric layer is planarized for uncovering the structure below and another structure layer is formed on top of the first. Alternatively, the dielectric layer is applied with a thickness two layers and the structure below is accessed by selective etching of the dielectric layer for selectively uncovering the top surface of the structure below. Multiple structure layer may also be formed in one step.

Description

AREA OF INVENTION[0001]The present invention relates to an etching and / or plating method for simplifying production of applications involving micro and nano structures in multiple layers. The method is particularly useful for fabrication of PWB (printed wiring boards), PCB (printed circuit boards), MEMS (micro electro mechanical systems), IC (integrated circuit) interconnects, above IC interconnects, sensors, flat panel displays, magnetic and optical storage devices, etc. Different types of structures in conductive polymers, structures in semiconductors, structures in metals, and others are possible to produce using this method. Even 3D-structures in silicon, by using formation of porous silicon, are possible to produce.BACKGROUND ART[0002]WO 02 / 103085 relates to an electrochemical pattern replication method, ECPR, and a construction of a conductive electrode for production of applications involving micro and nano structures. An etching or plating pattern, which is defined by a cond...

AI Technical Summary

Benefits of technology

[0016]An object of the present invention is to provide a method for forming multilayer structures, in which the risk of erosion or dishing has been reduced or even eliminated.

[0017]A further object is to provide a method of forming multilayer structures, in which the number of steps may be reduced.

Problems solved by technology

A problem of prior art multilayer methods is the fact that during the planarization step, at least two materials are required to be removed at the same time.

The problem is larger if the two materials have different properties, such as if one of the material is hard, such as a metal, and the other material is soft, such as a plastics material, glass material or porous material, for example a dielectricum.

If the planarization takes place by a mechanical polishing action or chemical-mechanical polishing action, several problems may arise.

During this stage, there is a risk that the underlying structure may be damaged, especially if the abrasion speed is high.

This may result in that the soft material is removed at a higher rate than the hard material, known as erosion or dishing, resulting in recessions in the soft material between the hard material.

The final result may be unsuitable for the following processing.

Another problem with mechanical planarization, it that there is a risk that the plate is not completely parallel with the structure layer formed.

A small angular deviation may result in that part of the structure is not uncovered as desired.

A further problem of prior art multilayer methods is the fact that the thickness of the structure layer may be difficult to control.

A still further problem of prior art multilayer methods is the fact that the prior art method requires many process steps, which makes the process cumbersome and expensive.

A yet further problem of prior art multilayer methods is the fact that it cannot fill vias or holes in the structure in an even manner.

Yet another problem is that it may be difficult to achieve a plane final result if the structures are relatively uneven from the start.

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