Method of forming a semiconductor device including trench termination

• US 9,773,693 B2
• Filed: 02/19/2016
• Issued: 09/26/2017
• Est. Priority Date: 10/21/2013
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Inventors: Grivna, Gordon M., Hossain, Zia, Salih, Ali
• Primary Examiner(s): Hossain, Moazzam
• Assistant Examiner(s): Lu, Farun
• Application Number:
  US15/047,874
• Publication Number:
  US 20160172234A1
• Time in Patent Office: 585 Days
• CPC Class Codes: H01L 21/76205 in a region being recessed from the surface, e.g. in a recess, groove, tub or trench region
• CPC Class Codes: H01L 21/76816 Aspects relating to the layout of the pattern or to the size of vias or trenches layout of the interconnections per se H01L23/528; CAD of ICs G06F30/00
• CPC Class Codes: H01L 29/0615 by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE] LDD or drain offset regions H01L29/7833
• CPC Class Codes: H01L 29/0649 Dielectric regions, e.g. SiO2 regions, air gaps
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• CPC Class Codes: H01L 29/7811 with an edge termination structure guard regions per se H01L29/0619; field plates per se H01L29/402
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

In an embodiment, a method of forming a semiconductor may include forming a plurality of active trenches and forming a termination trench substantially surrounding an outer periphery of the plurality of active trenches. The method may also include forming at least one active trench of the plurality of active trenches having corners linking trench ends to sides of active trenches wherein each active trench of the plurality of active trenches has a first profile along the first length and a second profile at or near the trench ends; and forming a termination trench substantially surrounding an outer periphery of the plurality of active trenches and having a second profile wherein one of the first profile or the second profile includes a non-linear shape.

Claims

1. A method of forming a semiconductor device comprising:

forming the semiconductor device on a silicon semiconductor substrate;

forming a plurality of active trenches in an active region of the semiconductor device including forming longitudinal sides of the plurality of active trenches extending along a first length in a first direction and forming trench ends at a distal ends of the plurality of active trenches wherein the trench ends have a first profile; and

forming a termination trench extending around an outer periphery of the plurality of active trenches including forming the termination trench having a second profile along a first side of the termination trench and forming a third profile along a second side of the termination trench that faces toward one or more trench ends and including forming a varying profile for one of the first profile or the third profile wherein the varying profile forms a first volume of semiconductor material in a first transition region that is positioned at least between a first corner of a first trench end of a first active trench of the plurality of active trenches and the second side of the termination trench, forms a second volume of semiconductor material that is one of between the first side of the termination trench and a longitudinal side of a first active trench of the plurality of active trenches or between the longitudinal side of the first active trench and a longitudinal side of a second active trench of the plurality of active trenches, and forms a third volume between a second corner of the first trench end and the second side of the termination trench, wherein the first volume and the third volume are no greater than the second volume.

2. The method of claim 1 wherein forming the varying profile includes forming the third profile to include one of a pocket near a first trench end of the first active trench or a protrusion that extends from the termination trench toward the first direction into a space between the first active trench and a second active trench of the plurality of active trenches.

3. The method of claim 1 wherein forming the varying profile includes forming an interior edge of the termination trench juxtaposed to the first trench end and forming the interior edge spaced a first distance from the first corner and forming a second distance between the longitudinal side of the first active trench and one of a longitudinal side of a second active trench or first side of the termination trench wherein the first distance is one of no greater than the second distance or less than the second distance.

4. The method of claim 3 further including forming the first distance to be between approximately fifty and seventy five percent of the second distance.

5. The method of claim 1 wherein forming the varying profile includes forming a trench tip having a first profile of one of a bulbous shape, a curved shape, diamond shape, rectangular shape, or a flared shape.

6. The method of claim 1 wherein forming the varying profile includes forming the first trench end to include a trench tip having a width that is greater than a width of the first active trench along the longitudinal side of the first active trench.

7. The method of claim 1 wherein forming the varying profile includes forming a substantially decreasing volume of semiconductor material that is positioned between the first trench corner and portions of the second side of the termination trench that are adjacent to the trench ends and corners.

8. The method of claim 1 wherein forming the termination trench includes forming a second section of the termination trench extending to touch an end of the second active trench including forming a trench conductor of the termination trench physically and electrically contacting a plate conductor of the second active trench.

9. The method of claim 1 further including forming the first profile to be substantially similar to the third profile.

10. A method of forming a semiconductor device comprising:

forming a plurality of active trenches with each active trench having a trench end at a distal end of each active trench including forming corners of each active trench linking trench ends to sides of the active trenches wherein each active trench of the plurality of active trenches has a first profile along sides and a second profile at or near the trench ends; and

forming a termination trench substantially surrounding an outer periphery of the plurality of active trenches and having a third profile along a first side of the termination trench and a fourth profile along a second side that faces at least one trench end wherein the second profile—

includes a non-linear shape and wherein a distance from a trench end to the termination trench is substantially no greater than a distance from any of the corners to the termination trench.

11. The method of claim 10 wherein forming the plurality of active trenches includes forming a first active trench of the plurality of active trenches having a first trench end with a width that is wider than a width of a longitudinal portion of the first active trench.

12. The method of claim 11 further including forming the first active trench end to have a shape that is one of an angular shape, a curved shape, a rectangular shape, a bulbous shape, a flared shape, or diamond shape.

13. The method of claim 10 wherein forming the termination trench includes forming the fourth profile to have a first non-linear shape that includes one of pockets or projections and forming a first corner of a first active trench of the plurality of active trenches spaced a first distance from the first non-linear shape and forming a longitudinal side of the first active trench spaced a second distance from one of the first side of the termination trench or a longitudinal side of a second active trench of the plurality of active trenches wherein the first distance is no greater than the second distance.

14. The method of claim 10 wherein forming the termination trench includes forming the fourth profile to include one of a pocket near a first trench end of a first active trench of the plurality of active trenches or a protrusion that extends from the termination trench toward the first active trench into a space between the first active trench and a second active trench of the plurality of active trenches.

15. The method of claim 10 further including forming the fourth profile to be substantially similar to the second profile.