Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
225 words
A method for making a dynamic random access memory comprising the steps of: preparing a substrate having a first surface and a second surface opposite the first surface; dividing the first surface of the substrate into a memory cell area and a peripheral area; recessing the memory cell area from the peripheral area by a first depth; forming a trench having a bottom area and a sidewall into the recessed memory area; forming a first insulated layer over the first surface; forming a contact hole through the first insulating layer; depositing and pattering a first conductive layer to form a storage node in electrical contact with the first surface of the substrate thorough the contact hole; forming a dielectric layer over the storage node; forming a second conductive layer over the dielectric layer to form a plate node; planarizing the first surface of the substrate; thinning the second surface of the substrate to expose the first insulating layer filled in the trench such that a portion of the second surface opposite the memory cell area has a thin silicon on insulator layer surrounded by the trench and a portion of the second surface opposite the peripheral area has a thick silicon on insulator layer; and forming switching elements on the second surface of thin silicon on insulator layer and the thick silicon on insulator layer.
Claim 2
Independent Claim
225 words
A method for making a dynamic random access memory comprising the steps of: preparing a substrate having a first surface and a second surface opposite the first surface; dividing the first surface of the substrate into a memory cell area and a peripheral area; recessing the memory cell area from the peripheral area by a first depth; forming a trench having a bottom area and a sidewall into the recessed memory area; forming a first insulated layer over the first surface; forming a contact hole through the first insulating layer; depositing and pattering a first conductive layer to form a storage node in electrical contact with the first surface of the substrate thorough the contact hole; forming a dielectric layer over the storage node; forming a second conductive layer over the dielectric layer to form a plate node; planarizing the first surface of the substrate; thinning the second surface of the substrate to expose the first insulating layer filled in the trench such that a portion of the second surface opposite the memory cell area has a thin silicon on insulator layer surrounded by the trench and a portion of the second surface opposite the peripheral area has a thick silicon on insulator layer; and forming switching elements on the second surface of thin silicon on insulator layer and the thick silicon on insulator layer.
Claim 3
Dependent Claim
50 words
The method of claim 1, wherein the step of depositing and patterning the first conductive layer comprises the substeps of: forming an undoped polysilicon layer over the first surface in contact with the first surface throughout the contact hole; and forming a doped polysilicon layer over the undoped polysilicon layer.
Claim 4
Dependent Claim
32 words
The method of claim 1, wherein the first depth is greater than the combined thickness of the first insulating layer, the first conductive layer, the dielectric layer, and the second conductive layer.
Claim 5
Dependent Claim
17 words
The method of claim 1, wherein the first surface is polished and planarized using chemical-mechanical polishing techniques.
Claim 6
Dependent Claim
25 words
The method of claim 4, further comprising the step of bonding a handling wafer to the planarized first surface prior to thinning the second surface.
Claim 7
Dependent Claim
22 words
The method of claim 1, further comprising the step of forming a planarizing layer before planarizing the first surface of the substrate.
Claim 8
Dependent Claim
50 words
The method of claim 6, wherein the step of depositing and patterning the first conductive layer comprises the substeps of: forming an undoped polysilicon layer over the first surface in contact with the first surface through the contact hole; and forming a doped polysilicon layer over the undoped polysilicon layer.