Semiconductor device manufacturing: process – Coating of substrate containing semiconductor region or of... – Insulative material deposited upon semiconductive substrate
Reexamination Certificate
2002-11-18
2003-08-05
Elms, Richard (Department: 2824)
Semiconductor device manufacturing: process
Coating of substrate containing semiconductor region or of...
Insulative material deposited upon semiconductive substrate
Reexamination Certificate
active
06602807
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the fabrication of semiconductor devices. More particularly, this invention relates to selective deposition of silicon oxide onto silicon substrates.
BACKGROUND OF THE INVENTION
Optimization of semiconductor fabrication sometimes requires a thicker nonconducting film on some components than on other components. Such films of different thicknesses can be made by traditional mask and etch techniques or by selective deposition of the reaction product of TEOS and ozone.
Traditional mask and etch methods of forming oxide layers and spacers of different thicknesses requires the application of a first mask over select parts of the semiconductor device and then depositing a layer of silicon oxide over the unmasked parts of the semiconductor device. The first mask is then removed and a second mask is applied over the parts that have been coated with the first silicon oxide layer leaving other parts unmasked. Subsequently, a second silicon oxide layer is deposited on the unmasked parts. Finally, an etch is used to remove silicon oxide from select surfaces, leaving behind an oxide layer or spacers where desired. This process adds a number of steps to the manufacturing procedures thereby increasing the complexity of the fabrication. As such, semiconductors are typically manufactured oxide with oxide layers or spacers of an intermediate thickness that will work acceptably, although not optimally, for substrates of different conductivity or composition.
The selective deposition of TEOS/ozone on silicon in preference to silicon nitride has been disclosed in the prior art. Copending U.S. patent application Ser. No. 09/652,188 filed Aug. 31, 2000 discloses selective deposition of TEOS/ozone wherein the selectivity is based on differences in the doping of silicon. In situations where these selective deposition techniques are usable they provide means to form different thickness oxide layers in one step, thereby saving process time. The current invention improves upon the selectivity of these methods.
A hallmark of the current invention is the provision of a process that selectively deposits silicon oxide based on the characteristics of the underlying substrate and pulsed delivery of the reactants.
SUMMARY OF THE INVENTION
The current invention is a method for enhancing selective depositing silicon oxide onto a substrate surface, wherein the selectivity is based on the conductivity and/or the composition of the substrate, by pulsing the delivery of the reactants.
One preferred embodiment is a method for selectively depositing silicon oxide onto a substrate, the method comprising the steps of: providing a substrate having at least one exposed region of silicon and at least one exposed region of silicon nitride and/or comprising at least one exposed silicon region of one type of conductivity and at least one exposed silicon region of a different type conductivity; delivering, via a linear injector, ozone and tetraethylorthosilicate into contact with the substrate and with each other, wherein the delivery of the ozone is pulsed on and off; and reacting the ozone and tetraethylorthosilicate in contact with the substrate to selectively deposit silicon oxide onto the substrate.
Another preferred embodiment is a method for selectively depositing silicon oxide onto a substrate, the method comprising the steps of: providing a substrate having at least one exposed region of silicon and at least one exposed region of silicon nitride and/or comprising at least one exposed silicon region of one type of conductivity and at least one exposed silicon region of a different type conductivity; delivering, via a linear injector, ozone and tetraethylorthosilicate into contact with the substrate and with each other, wherein the delivery of the ozone is pulsed on and off; and reacting the ozone and tetraethylorthosilicate in contact with the substrate to selectively deposit silicon oxide onto the substrate, wherein the reaction occurs at a temperature up to about 500° C. and a pressure of at least about 10 torr.
A further preferred embodiment is a method for selectively depositing silicon oxide onto a substrate, the method comprising the steps of providing a substrate having at least one exposed region of silicon and at least one exposed region of silicon nitride and/or comprising at least one exposed silicon region of one type of conductivity and at least one exposed silicon region of a different type conductivity; delivering, via a linear injector, ozone and tetraethylorthosilicate into contact with the substrate and with each other, wherein the delivery of the ozone and the delivery of the tetraethylorthosilicate are pulsed on and off alternately; and reacting the ozone and tetraethylorthosilicate in contact with the substrate to selectively deposit silicon oxide onto the substrate.
Still another preferred embodiment is a method for selectively depositing silicon oxide onto a substrate, the method comprising the steps of: providing a substrate having at least one exposed region of silicon and at least one exposed region of silicon nitride and/or comprising at least one exposed silicon region of one type of conductivity and at least one exposed silicon region of a different type conductivity; delivering, via a linear injector, ozone and tetraethylorthosilicate into contact with the substrate and with each other, wherein the delivery of the ozone and the delivery of the tetraethylorthosilicate are pulsed on and off alternately; and reacting the ozone and tetraethylorthosilicate in contact with the substrate to selectively deposit silicon oxide onto the substrate, wherein the reaction occurs at a temperature up to about 500° C. and a pressure of at least about 10 torr.
A further preferred embodiment is a semiconductor processing method of forming spacers of variable thickness, the method comprising the steps of: providing a silicon-comprising substrate having a surface comprising at least one first conductive region comprising either P-type silicon or non-doped silicon and at least one second conductive region, provided that: (1) when the first conductive region comprises P-type silicon, then the second conductive region comprises either non-doped silicon or N-type silicon; and, (2) when the first conductive region comprises non-doped silicon, then the second conductive region comprises N-type silicon; decomposing tetraethylorthosilicate with ozone to selectively deposit silicon oxide over the silicon surface and over both the first conductive region and the second conductive region, wherein delivery of the ozone is pulsed on and off whereby a greater thickness of silicon oxide is deposited on the first conductive region than on the second conductive region and delivery of the ozone and the tetraethylorthosilicate is via a linear injector; and, etching the silicon oxide deposited on the substrate to remove silicon oxide from the surface of the substrate, whereby the silicon oxide layers remaining on the first and second conductive regions provides a layer of variable thickness around the first conductive region and the second conductive region.
Another preferred embodiment is a semiconductor processing method of forming spacers of variable thickness, the process comprising the steps of: providing a silicon-comprising substrate having a surface comprising at least one first conductive region comprising either P-type silicon or non-doped silicon and at least one second conductive region, provided that: (1) when the first conductive region comprises P-type silicon, then the second conductive region comprises either non-doped silicon or N-type silicon; and, (2) when the first conductive region comprises non-doped silicon, then the second conductive region comprises N-type silicon; contacting silicon-comprising substrate with ozone and tetraethylorthosilicate wherein delivery of the ozone is pulsed on and off whereby the first conductive region and the second conductive region are in intimate contact with the ozone and the tetraethylorthosilicate and delivery of the ozone a
Budge William
Hill Christopher W.
Sandhu Gurtej S.
Elms Richard
Owens Beth E.
Whyte Hirschboeck Dudek SC
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