Method of multi-stage substrate etching and terahertz oscillator manufactured using the same method

Abstract

A method of multi-stage substrate etching, includes forming a first mask pattern on one surface of a first substrate; forming a hole by etching the first substrate using the first mask pattern as an etching mask; forming a second mask pattern on one surface of a second substrate; forming a hole by etching the second substrate to a predetermined depth using the second mask pattern as an etching mask; bonding the first and second substrates together such that an etched surface of the first substrate faces an etched surface of the second substrate; forming a third mask pattern on the second substrate; and forming a hole passing through the second substrate by etching the second substrate using the third mask pattern as an etching mask, whereby it is prevented the occurrence of a radius of curvature in the bottom surface and the overhang structure occurring on a step surface.

What is claimed is: 
     
         1 . A terahertz oscillator manufactured by a multi-stage substrate etching method and comprising two or more structures bonded together,
 wherein the method comprises the steps of:   forming a first mask pattern on one surface of a first substrate and forming a hole by etching the first substrate using the first mask pattern as an etching mask;   forming a second mask pattern on one surface of a second substrate and forming a hole by etching the second substrate to a predetermined depth using the second mask pattern as an etching mask;   bonding the first and second substrates together such that an etched surface of the first substrate faces an etched surface of the second substrate; and   forming a third mask pattern on the second substrate and forming a hole passing through the second substrate by etching the second substrate using the third mask pattern as an etching mask.   
     
     
         2 . The terahertz oscillator according to  claim 1 , wherein the step of forming a hole by etching the first substrate comprises the step of forming a photo resist (PR) coating on one surface of the first substrate, and forming an alignment key pattern on the PR coated surface. 
     
     
         3 . The terahertz oscillator according to  claim 2 , wherein the two or more structures are aligned with each other using the alignment key pattern formed on each structure, and wherein the two or more structures are bonded together using Si direct bonding or eutectic bonding.