Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having insulated gate
Reexamination Certificate
2001-10-04
2002-06-25
Tsai, Jey (Department: 2812)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having insulated gate
C438S253000, C438S255000
Reexamination Certificate
active
06410380
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the field of semiconductor manufacture and, more particularly, to a semiconductor device, e.g., a dynamic random access memory, incorporating an external electrical contact to a conductive layer, e.g., a cell plate of a capacitive storage cell, formed in the interior of the semiconductor device.
A dynamic random access memory (DRAM) chip is an example of a semiconductor device where reliable electrical contacts to an internal conductive layer must be provided. A DRAM chip is a rectangular array of individual circuits organized to store binary information through storage of different levels of voltage in a capacitive charge storage region of the DRAM chip. A transistor structure, including a plurality of transistors, is provided in the DRAM chip to provide access to the charge stored in each charge storage region. Each transistor functions as an on-off switch to open the communication lines between the charge storage region and a microprocessor in communication with the DRAM chip.
A network of electrically conductive cell plate contacts must be provided within the structure of the DRAM chip to enable storage of non-zero voltage levels in each charge storage region. Reliable storage is directly dependent upon the integrity of the cell plate contact. Accordingly, it is necessary to provide cell or top plate contacts characterized by low contact resistance.
Accordingly, there is a continuing need for semiconductor devices incorporating reliable electrical contacts to internal conductive layers.
SUMMARY OF THE INVENTION
This need is met by the present invention wherein a semiconductor device, e.g., a dynamic random access memory, is provided incorporating a reliable electrical contact to a conductive layer within the semiconductor device, e.g., a cell or top plate of a capacitive storage cell.
In accordance with one embodiment of the present invention, a method of fabricating a storage container structure is provided comprising the steps of: providing a substrate including a semiconductor structure; forming a patterning stop region; forming an insulating overlayer over a first surface of the substrate and over the patterning stop region; patterning a container region within the insulating overlayer such that the container region defines a container cross section having container side walls, a container bottom wall, and a container interior bounded in part by the container side walls and the container bottom wall, and such that the container bottom wall is at least partially defined by a surface of the patterning stop region; layering a first conductive film over an interior surface of the container region; layering an intermediate insulating film over the first conductive film; layering a second conductive film over the intermediate insulating film such that the second conductive film includes a first film portion characterized by a first film thickness and a second film portion characterized by a second film thickness, such that the second film thickness is greater than the first film thickness, and such that the second film portion occupies at least a portion of the container interior; patterning a contact region in the second film portion of the second conductive film; and forming an electrical contact in the contact region such that respective portions of the electrical contact, the second conductive film, the intermediate insulating film, and the first conductive film occupy collectively at least a portion of the container region.
The respective portions of the electrical contact, the second conductive film, the intermediate insulating film, and the first conductive film preferably occupy collectively substantially all of the container region. The patterning stop region may be formed over the first surface of the substrate, within the substrate, or on the substrate. The container region is preferably patterned such that it further defines an upper boundary of the container cross section and the second conductive film is preferably layered such that the second film portion extends from the intermediate insulating film to at least the upper boundary of the container region. The contact region is preferably patterned, and the electrical contact is formed, such that the contact region and the electrical contact extend into the container region beyond the second film portion of the second conductive film.
In accordance with another embodiment of the present invention, a method of fabricating a storage container structure is provided comprising the steps of: providing a substrate including a semiconductor structure; forming a patterning stop region; forming an insulating overlayer over a first surface of the substrate and over the patterning stop region; patterning a container region within the insulating overlayer by removing a portion of an upper overlayer surface, a portion of an intermediate overlayer portion, and a portion of a lower overlayer surface such that (i) the container region defines a container cross section having container side walls, a container bottom wall, an upper container boundary, and a container interior bounded by the upper container boundary, the container side walls, and the container bottom wall, (ii) the upper container boundary is defined by the removed portion of the upper overlayer surface, (iii) the container side walls are defined by the insulating overlayer, and (iv) the container bottom wall is at least partially defined by a surface of the patterning stop region; layering a first conductive film over an interior surface of the container region; layering an intermediate insulating film over the first conductive film; layering a second conductive film over the intermediate insulating film such that the second conductive film includes a first film portion characterized by a first film thickness and a second film portion characterized by a second film thickness, such that the second film thickness is greater than the first film thickness, and such that the second film portion occupies at least a portion of the container interior; patterning a contact region in the second film portion of the second conductive film such that the contact region extends into the container region; and forming an electrical contact in the contact region such that respective portions of the electrical contact, the second conductive film, the intermediate insulating film, and the first conductive film occupy collectively at least a portion of the container region. The respective portions of the electrical contact, the second conductive film, the intermediate insulating film, and the first conductive film preferably occupy collectively substantially all of the container region.
In accordance with yet another embodiment of the present invention, a method of fabricating a storage container structure is provided comprising the steps of: providing a substrate including a semiconductor structure; forming a patterning stop region such that the patterning stop region includes a central stop region, a first lateral stop region, and a second lateral stop region; forming an insulating overlayer over a first surface of the substrate and over the patterning stop region; patterning a container region within the insulating overlayer such that the container region defines a container cross section having a container bottom wall, a first side wall including a first upper side wall portion and a first lower side wall portion, and a second side wall including a second upper side wall portion and a second lower side wall portion, and such that (i) the first upper side wall portion and the second upper side wall portion define an upper container portion therebetween, (ii) the first lower side wall portion and the second lower side wall portion define a lower container portion therebetween, (iii) the upper container portion is wider than the lower container portion, (iv) the container bottom wall is defined by the central stop region, (v) the first lower side wall portion is defined by a lateral surface of the first lateral stop regi
Killworth, Gottman Hagan & Schaeff LLP
Micro)n Technology, Inc.
Tsai Jey
LandOfFree
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