Method of fabricating suspended structure

• US 7,531,457 B2
• Filed: 11/21/2006
• Issued: 05/12/2009
• Est. Priority Date: 06/19/2006
• Status: Expired due to Fees

• Current Assignee: TOUCH MICRO-SYSTEM TECHNOLOGY CORP. (Walsin Lihwa Corporation)
• Original Assignee: TOUCH MICRO-SYSTEM TECHNOLOGY CORP. (Walsin Lihwa Corporation)
• Inventors: Kang, Yu-Fu, Yang, Chen-Hsiung
• Primary Examiner(s): LEBENTRITT, MICHAEL
• Application Number:
  US11/561,902
• Publication Number:
  US 20070293023A1
• Time in Patent Office: 903 Days
• Field of Search: 438/330, 438/412, 438/689, 438/680, 438/682, 438/683, 438/724, 438/736, 257/E21.17, 257/226, 257/334, 257/577, 257/E23.012, 257/E21.273, 257/E21.576
• US Class Current: 438/680
• CPC Class Codes: B81C 1/0015 Cantilevers switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244
• CPC Class Codes: B81C 2201/0108 Sacrificial polymer, ashing of organics
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling

Abstract

A method of fabricating a suspended structure. First, a substrate including a photoresist layer hardened by heat is provided. Subsequently, the hardened photoresist layer is etched so as to turn the photoresist layer into a predetermined edge profile. Thereafter, a structure layer is formed on parts of the substrate and parts of the photoresist layer. Next, a dry etching process is performed so as to remove the photoresist layer, and to turn the structure layer into a suspended structure.

Claims

1. A method of fabricating a suspended structure comprising:

providing a substrate, the substrate comprising a first patterned photoresist layer thereon;

heating the first patterned photoresist layer so as to harden the first patterned photoresist layer and to round an edge of the first patterned photoresist layer;

etching the first patterned photoresist layer to adjust a sidewall shape of the first patterned photoresist layer;

forming a second patterned photoresist layer on the substrate, the second patterned photoresist layer exposing a part of the first patterned photoresist layer and a part of the substrate;

forming a structure layer on the substrate, the first patterned photoresist layer, and the second patterned photoresist layer;

performing a lift off process to remove the second patterned photoresist layer and the structure layer above the second patterned photoresist layer; and

performing a dry etching process to remove the first patterned photoresist layer so that the structure layer turns into the suspended structure.

2. The method of claim 1, wherein the step of etching the first patterned photoresist layer to adjust the sidewall shape of the first patterned photoresist layer comprises:

forming an etching mask on the first patterned photoresist layer, the etching mask exposing a part of the first patterned photoresist layer;

etching the first patterned photoresist layer; and

removing the etching mask.

3. The method of claim 1, wherein the structure layer comprises metal, single crystal silicon, amorphous silicon, or polysilicon.

4. The method of claim 1, wherein the dry etching process comprises a dry chemical etching process or a reactive ion etching process.

5. A method of fabricating a suspended structure comprising:

providing a substrate, the substrate comprising a first patterned photoresist layer thereon;

heating the first patterned photoresist layer so as to harden the first patterned photoresist layer;

forming an etching mask on the first patterned photoresist layer and the substrate, the etching mask exposing a part of the first patterned photoresist layer;

etching a part of the first patterned photoresist layer not covered by the etching mask so that the first patterned photoresist layer comprises a predetermined shape;

removing the etching mask;

forming a structure layer on the substrate and the first patterned photoresist layer; and

performing a dry etching process to remove the first patterned photoresist layer so that the structure layer turns into the suspended structure.

6. The method of claim 5, wherein the predetermined shape of the first patterned photoresist layer comprises a vertical sidewall.

7. The method of claim 5, wherein the predetermined shape of the first patterned photoresist layer comprises an outwardly inclined sidewall.

8. The method of claim 5, wherein the predetermined shape of the first patterned photoresist layer comprises an inwardly inclined sidewall.

9. The method of claim 5, wherein the etching mask comprises metal.

10. The method of claim 5, wherein the structure layer comprises metal, single crystal silicon, amorphous silicon, or polysilicon.

11. The method of claim 5, wherein the step of etching the first patterned photoresist layer not covered by the etching mask comprises a plasma etching process or a reactive ion etching process.

12. The method of claim 5, wherein the dry etching process comprises a dry chemical etching process or a reactive ion etching process.