Method of forming an undercut microstructure

• US 8,377,320 B2
• Filed: 07/23/2010
• Issued: 02/19/2013
• Est. Priority Date: 04/13/2010
• Status: Expired due to Fees

• Current Assignee: National Taipei University Of Technology
• Original Assignee: National Taipei University Of Technology
• Inventors: Wang, Tzyy-Jiann, Tsou, Yueh-Hsun
• Primary Examiner(s): Hassanzadeh, Parviz
• Assistant Examiner(s): Klunk, Margaret D
• Application Number:
  US12/842,334
• Publication Number:
  US 20110250397A1
• Time in Patent Office: 942 Days
• Field of Search: 216/48, 438/31, 438369-377, 438418-419, 438/705, 438/739
• US Class Current: 216/48
• CPC Class Codes: B81B 2203/0384 sloped profile
• CPC Class Codes: B81C 1/00103 Structures having a predefined profile, e.g. sloped or rounded grooves
• CPC Class Codes: B81C 1/00571 Avoid or control under-cutting
• CPC Class Codes: B81C 2201/0136 by doping limited material regions
• CPC Class Codes: G02B 2006/1204 Lithium niobate (LiNbO3)
• CPC Class Codes: G02B 2006/12045 Lithium tantalate (LiTaO3)
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/136 by etching
• CPC Class Codes: Y10T 428/24479 including variation in thickness

Abstract

A method of forming an undercut microstructure includes: forming an etch mask on a top surface of a substrate; forming, on a top surface of the etch mask, an ion implantation mask having a top surface that is smaller than the top surface of the etch mask and that does not extend beyond the top surface of the etch mask; ion implanting the substrate in the presence of the etch mask and the ion implantation mask so that a damaged region is generated at a depth below an area of the surface that is not masked by the ion implantation mask; and etching the surface of the substrate until the damaged region is removed.

Claims

1. A method of forming an undercut microstructure having a trunk portion and an enlarged top end portion that is connected to the trunk portion, the method comprising:

forming an etch mask on a top surface of a substrate;

forming, on a top surface of the etch mask, an ion implantation mask having a top surface that is smaller than the top surface of the etch mask and that does not extend beyond the top surface of the etch mask;

ion implanting the substrate in the presence of the etch mask and the ion implantation mask so that a damaged region is generated at a depth below an area of the surface that is not masked by the ion implantation mask; and

etching the surface of the substrate until the damaged region is removed.

2. The method of claim 1, wherein the etch mask is made from one of photoresists, dielectrics, and metals, the ion implantation mask being made from one of photoresists, dielectrics, and metals.

3. The method of claim 1, wherein the etching of the substrate is conducted by one of wet etching techniques, reactive ion etching techniques, plasma etching techniques, and inductively coupled plasma etching techniques.

4. The method of claim 1, further comprising removing the ion implantation mask after ion implantation and prior to the etching of the substrate.

5. The method of claim 1, further comprising removing the etch mask after the etching of the ion implanted substrate.

6. The method of claim 1, wherein formation of each of the etch mask and the ion implantation mask is performed by coating, followed by lithography, the lithography being conducted through one of photolithography techniques and electron-beam lithography techniques.