Method and structure of manufacturing a high-Q inductor with an air trench

• US 6,326,673 B1
• Filed: 03/02/1999
• Issued: 12/04/2001
• Est. Priority Date: 08/07/1998
• Status: Expired due to Term

• Current Assignee: Winbond Electronics Corporation
• Original Assignee: Winbond Electronics Corporation
• Inventors: Liou, Ping
• Primary Examiner(s): Picardat, Kevin M.
• Assistant Examiner(s): COLLINS, DEVEN M
• Application Number:
  US09/260,597
• Time in Patent Office: 1,008 Days
• Field of Search: 257/531, 257/528, 257/529, 257/499
• US Class Current: 257/531
• CPC Class Codes: H01F 2017/0046 with a conductive path having a bridge
• CPC Class Codes: H01L 21/764 Air gaps H01L21/76264 takes precedence
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 27/08 including only semiconductor components of a single kind
• CPC Class Codes: H01L 28/10 Inductors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

The structure of high-Q inductor applied in a monolithic circuit according to the invention comprises a plurality of spiral metal lines and a plurality of dielectric layers, each dielectric layer formed between two adjacent spiral metal lines. Furthermore, via plugs are formed in each dielectric layer to electrically connect two adjacent spiral metal lines. A spiral air trench is formed along the spacing of the spiral metal lines in the dielectric layers. Therefore, 3D-structure of the inductor of the invention can greatly reduce the series resistance thereof without widening the spiral metal lines. In addition, the spiral air trench, filled with air which has a lower dielectric constant, can efficiently reduce the parasitic capacitance between the spacing of the spiral metal lines. As a result, the inductor of the invention has a higher quality factor at a proper RF operating frequency region.

Claims

1. A structure of an inductor with an air trench, comprising:

a substrate;

a plurality of spiral metal lines formed over the substrate;

a plurality of dielectric layers, each of which is formed between two adjacent spiral metal lines;

a plurality of via plug formed in the dielectric layers to connect the spiral metal line to each other;

a spiral air trench formed along the spacing of the spiral metal lines in the dielectric layers;

a first connective line connecting the outer end of an upper spiral metal line.

2. The structure ass recited in claim 1, wherein each spiral metal line is a spiral aluminum layer.

3. The structure as recited in claim 1, wherein each via plug is a tungsten plug.

4. The structure as recited in claim 1, wherein each dielectric layer is a silicon oxide layer.

5. The structure as recited in claim 1, further comprising a first bonding pad connected to the first connective line and a second bonding pad connected to the second connective line.

6. The structure as recited in claim 1, wherein each spiral metal line is a square spiral metal line.