Method of forming a semiconductor device including trench termination and trench structure therefor

• US 9,299,776 B2
• Filed: 06/05/2014
• Issued: 03/29/2016
• 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): Abdelaziez, Yasser A
• Assistant Examiner(s): Lu, Farun
• Application Number:
  US14/297,204
• Publication Number:
  US 20150108569A1
• Time in Patent Office: 663 Days
• Field of Search: 257/301, 257E27091-E27095, 257E292-E29201, 257/E29.257, 257/E29.346, 257/E21.396, 257E21545-E21553, 257/E21.564, 257/E21.585, 257/E21.651, 257/E21.655, 438/242, 438/248, 438/259, 438386-391, 438/700
• US Class Current: 1/1
• 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 semiconductor device comprising:

a semiconductor substrate having an active region and an inactive region;

a plurality of active trenches formed in the active region, a first active trench of the plurality of active trenches having a longitudinal portion extending a first distance in a first direction along an axis and having trench ends at distal ends of the first active trench;

an outer periphery of the plurality of active trenches wherein a first portion of the outer periphery extends along the first direction and a second portion of the outer periphery extends in second direction different from the first direction;

a plate conductor within the first active trench;

a termination trench substantially surrounding the outer periphery of the plurality of active trenches;

a termination conductor within the termination trench;

a longitudinal side of the termination trench extending in the first direction outside the outer periphery of the plurality of active trenches; and

a second side of the termination trench outside the second portion of the outer periphery of the plurality of active trenches, a first section of the second side of the termination trench juxtaposed to a first trench end of the first active trench wherein the first section includes a non-linear shape including one of a scalloped shape or angular shape or projection shape or flared shape or diamond shape, the first section positioned to form a second distance between an interior edge of the first section and a first corner of the first trench end of the first active trench and between the interior edge and a second corner of the first trench end of the first active trench, and to form a third distance between one of a longitudinal side of the first active trench and a longitudinal side of an adjacent active trench or between the longitudinal side of the first active trench and the longitudinal side of the termination trench wherein the second distance is substantially one of no greater than or less than the third distance.

2. The semiconductor device of claim 1 further including a second section of the second side of the termination trench extending to touch an end of the adjacent active trench of the plurality of active trenches wherein the termination conductor of the termination trench physically and electrically contacts the plate conductor of the adjacent active trench.

4. The semiconductor device of claim 1 wherein the first trench end of the first active trench has a shape that is one of a curved shape, a flared end shape, bulb shape, rectangular shape, or diamond shape.

6. The semiconductor device of claim 1 wherein the second distance is between approximately fifty to seventy five percent of the third distance.

7. The semiconductor device of claim 1 wherein the termination trench includes a projection extending a fourth distance away from the termination trench into a space between the first active trench and an adjacent active trench and spaced away from the trench ends of the first active trench and the adjacent active trench.

8. The semiconductor device of claim 1 wherein the first trench end of the first active trench has a width that is greater than a width of the longitudinal portion of the first active trench.

3. A semiconductor substrate having an active region and an inactive region;

a plurality of active trenches formed in the active region, a first active trench of the plurality of active trenches having a longitudinal portion extending a first distance in a first direction along an axis and having trench ends at distal ends of the first active trench;

an outer periphery of the plurality of active trenches wherein a first portion of the outer periphery extends along the first direction and a second portion of the outer periphery extends in second direction different from the first direction;

a plate conductor within the first active trench;

a termination trench substantially surrounding the outer periphery of the plurality of active trenches;

a termination conductor within the termination trench;

a longitudinal side of the termination trench extending in the first direction outside the outer periphery of the plurality of active trenches;

a second side of the termination trench outside the second portion of the outer periphery of the plurality of active trenches, a first section of the second side of the termination trench juxtaposed to a first trench end of the first active trench wherein the first section includes a non-linear shape including one of a scalloped shape or angular shape or projection shape or flared shape or diamond shape, the first section positioned to form a second distance between an interior edge of the first section and a first corner of the first trench end of the first active trench, and to form a third distance between one of a longitudinal side of the first active trench and a longitudinal side of an adjacent active trench or between the longitudinal side of the first active trench and the longitudinal side of the termination trench wherein the second distance is substantially one of no greater than or less than the third distance; and

wherein the termination conductor physically and electrically contacts the plate conductor of every other active trench of the plurality of active trenches.

5. A semiconductor substrate having an active region and an inactive region;

a plurality of active trenches formed in the active region, a first active trench of the plurality of active trenches having a longitudinal portion extending a first distance in a first direction along an axis and having trench ends at distal ends of the first active trench;

an outer periphery of the plurality of active trenches wherein a first portion of the outer periphery extends along the first direction and a second portion of the outer periphery extends in second direction different from the first direction;

a plate conductor within the first active trench;

a termination trench substantially surrounding the outer periphery of the plurality of active trenches;

a termination conductor within the termination trench;

a longitudinal side of the termination trench extending in the first direction outside the outer periphery of the plurality of active trenches; and

a second side of the termination trench outside the second portion of the outer periphery of the plurality of active trenches, a first section of the second side of the termination trench juxtaposed to a first trench end of the first active trench wherein the first section includes a non-linear shape including one of a scalloped shape or angular shape or projection shape or flared shape or diamond shape, the first section positioned to form a second distance between an interior edge of the first section and a first corner of the first trench end of the first active trench, and to form a third distance between one of a longitudinal side of the first active trench and a longitudinal side of an adjacent active trench or between the longitudinal side of the first active trench and the longitudinal side of the termination trench wherein the second distance is substantially one of no greater than or less than the third distance; and

wherein the second distance between the first corner of the first trench end of the first active trench and the interior edge of the termination trench reduces a volume of semiconductor material between the first corner of the first trench end of the first active trench and the interior edge of the termination trench.

9. The semiconductor device of claim 5 wherein the first trench end of the first active trench has a shape that is one of a curved shape, a flared end shape, bulb shape, rectangular shape, or diamond shape.