1. A holding device for grasping a flat item, comprising:
a hub having a front side for confronting the item and an opposite back side; and
a plurality of grappling assemblies rotatably attached to said hub, each grappling assembly including:
an elongated tension member having first and second end portions, said tension member extending around a thimble attached to said hub, and
a hook sized and adapted to engage an edge of the item, said hook including a body portion and at least one arm extending therefrom, wherein said body portion includes a cavity with first and second open ends, said first and second end portions extending into said first open end and a jaw fitting extending into said second open end, said jaw fitting operative to grasp said first and second end portions.
2. A holding device according to claim 1, further comprising a bracket removably engaged with the back side of said hub.
3. A holding device according to claim 1, wherein each thimble comprises an arcuate channel extending around an aperture formed through each thimble.
4. A holding device according to claim 3, wherein each thimble is rotatably attached to said hub with a fastener extending through said hub and each aperture.
5. A holding device according to claim 1, wherein each said hook includes a pair of arms extending therefrom.
6. A holding device according to claim 5, wherein each arm extends laterally from said body portion and are joined together with an arcuate bridge portion.
7. A holding device according to claim 5, wherein said arm includes a right angle bend.
8. A holding device according to claim 5, further comprising a resilient pad disposed on said front side of said hub and an additional resilient pad disposed on each said body portion.
9. A holding device for grasping a flat item, comprising:
a hub having a front side for confronting the item and an opposite back side;
a plurality of elongated tensioning members rotatably attached to the back side of the hub, wherein each tensioning member has first and second end portions, each tensioning member extending around a fastener attached to the hub; and
each tensioning member including a hook adapted to engage an edge of the item, said hook including a body portion and a pair of arms extending laterally therefrom, wherein said body portion includes a cavity with first and second open ends, said first and second end portions extending into said first open end and a jaw fitting extending into said second open end, said jaw fitting operative to grasp said first and second end portions.
10. A holding device according to claim 9, wherein each jaw fitting includes a pair of tangs each tang including at least one tooth for engaging a corresponding tensioning member.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A vertical semiconductor power MOS device comprising a plurality of semiconductor power cells with each cell comprising a plurality of trench gates surrounded by a plurality of source regions above a plurality of body regions above a drain region disposed on a bottom surface of a substrate, wherein said trench MOSFET further comprising:
a substrate of a first type conductivity;
an epitaxial layer of said first type conductivity over said substrate, having a lower doping concentration than said substrate;
a plurality of trenches extending into said epitaxial layer, surrounded by a plurality of source regions of said type conductivity above said body regions of the second type conductivity;
a first insulating layer lining said trenches as gate dielectric;
a doped polysilicon of the first type conductivity as gate regions overlying said insulating layer;
a second insulating layer disposed over said epitaxial layer to isolate source metal which contacts to said both source and body region, from said doped polysilicon as said gate regions;
a plurality of source-body contact trenches opened with sidewalls substantially perpendicular to a top epitaxial surface within said source regions and with tapered sidewalls respect to said top surface into said body regions;
a front metal disposed on front surface of device as source metal; and
a backside metal disposed on backside of said substrate as drain metal.
2. The trench MOSFET of claim 1, wherein the angle between said source-body contact trench sidewalls and said top surface is 90\xb15 degree within said source regions and is less than 85 degree within said body regions.
3. The trench MOSFET of claim 1, wherein said second insulating layer is SRO (Silicon Rich Oxide).
4. The trench MOSFET of claim 1, wherein said second insulating layer is combination of SRO and PSG or BPSG to further reduce source contact resistance.
5. The trench MOSFET of claim 1, wherein said source-body contact trenches are filled with TiTiNW.
6. The trench MOSFET of claim 1, wherein said source-body contact trenches are filled with CoTiNW.
7. The trench MOSFET of claim 1, wherein said source-body contact trenches are filled with TiTiNAl alloys.
8. The trench MOSFET of claim 1, wherein said source metal is Al alloys, TiAl alloys, TiTiNAl alloys, TiNiAg or Cu.
9. A method for manufacturing a trench MOSFET with improved source contact structure comprising the steps of:
growing an epitaxial layer upon a heavily N doped substrate, wherein said epitaxial layer is doped with a first type dopant, eg., N dopant;
forming a trench mask with open and closed areas on the surface of said epitaxial layer;
removing semiconductor material from exposed areas of said trench mask to form a plurality of gate trenches;
depositing a sacrificial oxide layer onto the surface of said trenches to remove the plasma damage introduced during opening said trenches;
removing said sacrificial oxide and said trench mask;
depositing a first insulating layer on the surface of said epitaxial layer and along the inner surface of said gate trenches as gate oxide;
depositing doped poly or combination of doped poly and undoped poly onto said gate oxide and into said gate trenches;
etching back or CMP said doped poly from the surface of said gate oxide and leaving enough doped poly into said gate trenches to serve as trench gate material;
forming silicide on top poly as alternative for low Rg;
implanting said epitaxial layer with a second type dopant to from P-body regions;
implanting whole device with a first type dopant to form source regions;
forming a second insulating layer onto whole surface;
forming a contact mask on the surface of said second insulating layer and removing insulating material and semiconductor material;
implanting BF2 ion to form P+ area wrapping sidewalls and bottom of source-body contact trench within P-body reigon;
cleaning oxide along the inner surface of source-body contact trench with dilute HF as pre-TiTiN clean;
depositing TiTiNW or CoTiNW consequently into source-body contact trenches and on the front surface;
etching back W and TiTin or CoTiN to form source-body contact metal plug and depositing a layer of Al alloys on the front and rear side of device, respectively.
10. The method of claim 9, wherein forming said gate trenches comprises etching said epitaxial layer according to the open areas of said trench mask by dry silicon etching.
11. The method of claim 9, wherein forming said P-body regions comprises a step of diffusion to achieve a certain depth after P-body implantation step.
12. The method of claim 9, wherein forming said source regions comprises a step of diffusion to achieve a certain depth after n+ Ion Implantation step.
13. The method of claim 9, wherein said second insulating layer is SRO or combination of SRO and PSG or BPSG.
14. The method of claim 9, wherein forming said source-body contact trench comprises etching through said SRO layer and gate oxide layer by dry oxide etching according to the exposed areas of said contact mask.
15. The method of claim 9, wherein forming said source-body contact trench comprises etching through PSG or BPSG layer with a larger width, etching through SRO and gate oxide layer with a smaller width.
16. The method of claim 9, wherein forming said source-body contact trench comprises etching through said n+ source regions and into said P-body regions by dry silicon etching according to the exposed areas of said contact mask.
17. The method of claim 9, wherein implanting BF2 ion to form P+ area comprises implanting BF2 ion above source-body contact trench as well as above the second insulating layer.
18. The method of claim 9, wherein implanting BF2 ion to form P+ area comprises implanting BF2 ion only above source-body contact trench.