Inmos Limited

Sgs-Thomson Microelectronics Limited

Howard Charles Nicholls

Michael John Norrington

Michael K Thompson

Graeme Michael Wyborn

Christopher McGee

A method of fabricating a tungsten contact in a semiconductor device comprises providing an oxide layer on a region of a silicon substrate; depositing a sealing dielectric layer over the oxide layer; and depositing an interlevel dielectric layer over the sealing layer. The interlevel dielectric layer, the sealing dielectric layer and the oxide layer are then etched through as far as the substrate thereby to form a contact hole and to expose the said region. A dopant is implanted into the said region whereby the implanted dopant is self-aligned to the contact hole. The substrate is thermally annealed. Tungsten is selectively deposited in the contact hole and an interconnect layer is deposited over the deposited tungsten contact. The invention also provides a semiconductor device which incorporates a tungsten contact and which can be fabricated by the method.

Semiconductor devices and fabrication thereof

Semiconductor device with a tungsten contact

A method of fabricating a tungsten contact in a semiconductor device, the method including the steps of: (a) providing a silicon wafer structure including a dielectric layer and an underlying layer selected from a semiconductor or electrically conductive material, the dielectric layer being patterned to expose a contact portion of the underlying layer; and (b) depositing by chemical vapor deposition a tungsten layer over the dielectric layer and the contact portion, the deposition being carried out by reaction of a tungsten-containing component and a reducing agent which are introduced into the vicinity of the silicon wafer structure, the deposition step having a first phase in which the process conditions are controlled to form a seed layer of tungsten on the dielectric layer and a second phase in which the process conditions are modified from the first phase to form a blanket tungsten layer over the seed layer which acts as an adhesion layer between the dielectric layer and the blanket tungsten layer. The invention also provides a semiconductor device incorporating a tungsten contact which is disposed in a contact hole of a dielectric layer, the tungsten contact including a seed layer of tungsten which extends over the dielectric layer surface and an overlying layer of blanket tungsten.

Manufacture of semiconductor devices

A semiconductor device comprising a silicon substrate, an oxide layer on the silicon substrate, a doped polysilicon region disposed on the oxide layer, a dielectric layer which has been deposited over the doped polysilicon region and the silicon substrate, a contact hole which is formed in the dielectric layer and extends over respective laterally adjacent portions of the doped polysilicon region and the silicon substrate and a contact which has been selectively deposited in the contact hole which electrically connects the said portions together. The invention also provides a method of fabricating a semiconductor device incorporating a refractory metal contact, the method comprising the steps of: a) providing a semiconductor substrate having an oxide layer thereon and a doped polysilicon region disposed on the oxide layer; (b) depositing a dielectric layer over the doped polysilicon region and over the silicon substrate; (c) forming a contact hole in the dielectric layer which exposes a portion of the doped polysilicon region and a laterally adjacent portion of the silicon substrate; and (d) selectively depositing a contact into the contact hole thereby electrically to connect together the doped polysilicon region and the silicon substrate.

Semiconductor device incorporating a contact and manufacture thereof

A semiconductor device comprising a silicon substrate, an oxide layer on the silicon substrate, a doped polysilicon region disposed on the oxide layer, a dielectric layer which has been deposited over the doped polysilicon region and the silicon substrate, a contact hole which is formed in the dielectric layer and extends over respective laterally adjacent portions of the doped polysilicon region and the silicon substrate and a contact which has been selectively deposited in the contact hole which electrically connects the said portions together. The invention also provides a method of fabricating a semiconductor device incorporating a refractory metal contact, the method comprising the steps of:--a) providing a semiconductor substrate having an oxide layer thereon and a doped polysilicon region disposed on the oxide layer; (b) depositing a dielectric layer over the doped polysilicon region and over the silicon substrate; (c) forming a contact hole in the dielectric layer which exposes a portion of the doped polysilicon region and a laterally adjacent portion of the silicon substrate; and (d) selectively depositing a contact into the contact hole thereby electrically to connect together the doped polysilicon region and the silicon substrate.

Method of manufacturing a semiconductor device incorporating a

A method of fabricating a semiconductor device incorporating a via and an interconnect layer of aluminium or aluminium alloy. The invention provides a semiconductor device including a via and an interconnect layer of aluminium or aluminium alloy, a capping layer of electrically conductive material which has been formed over the interconnect layer and an electrically conductive contact which has been selectively deposited on the capping layer thereby to form a via, the materials of the capping layer and of the contact being selected whereby at the interface therebetween there is substantial absence of non-conductive compounds formed from the material of the capping layer.

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Cardiff, United Kingdom

Howard Charles Nicholls