Semiconductor device manufacturing: process – Making passive device – Resistor
Reexamination Certificate
1999-02-24
2001-12-11
Fourson, George (Department: 2823)
Semiconductor device manufacturing: process
Making passive device
Resistor
C438S010000, C438S017000
Reexamination Certificate
active
06329262
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor integrated circuit including a tungsten silicide nitride (WSiN) film formed on a semiconductor substrate and a method for producing the same.
2. Description of the Related Art
In order to realize a temperature-compensating function by compensating for temperature characteristics of a semiconductor integrated circuit (hereinafter, also simply referred to as an “integrated circuit”), a thermal resistor is generally used. Hereinafter, a prior art semiconductor integrated circuit using a thermal resistor will be described.
Specifically, a thermal resistor made of a metal oxide, or the like, having a negative temperature coefficient is provided as a thermistor resistor at an external position of an integrated circuit in such a manner as to be thermally connected to the integrated circuit, whereby a temperature-compensating function is realized by utilizing the changes in resistance of the thermistor resistor due to the increase in temperature. Japanese Laid-open publication No. 2-44701 discloses a method in which a thermal resistor made of a tungsten nitride (WN) film is provided in an integrated circuit, and the resistance of the resistor is adjusted by annealing.
However, with the structure in which a thermistor resistor is externally provided to an integrated circuit, the size of the thermistor resistor is generally almost the same as that of the integrated circuit, so that the size of an entire circuit obtained by using the integrated circuit becomes large. Furthermore, according to the conventional technique, it is difficult to produce a thermistor resistor having a desired temperature coefficient with good precision, and the resultant thermistor resistor has temperature coefficient characteristics varied in a wide range. Therefore, it is required that a thermistor resistor having appropriate temperature coefficient characteristics be selected.
According to the above-mentioned method in which a thermal resistor made of a WN film is provided in an integrated circuit, and the resistance of the resistor is adjusted by annealing, the entire semiconductor wafer is heated by annealing. Therefore, there is a possibility that other circuit elements formed on the wafer are subject to damage during annealing. Furthermore, the changes in wafer temperature may be delayed in terms of time at the beginning and ending of heating during annealing, which prevents the resistance from being adjusted with good precision. In addition, it is difficult to complete the adjustment of the resistance within a short period of time.
In addition, although the WN film can be formed so as to have a negative temperature coefficient suitable for a thermistor resistor, the temperature coefficient cannot be set to be large enough. Furthermore, depending upon the production conditions, the temperature coefficient becomes positive, causing problems with using a thermistor resistor which should exhibit a temperature-compensating function.
SUMMARY OF THE INVENTION
The semiconductor integrated circuit of the present invention includes a thermal resistor which is made of tungsten silicide nitride containing at least about 5% by weight of silicon and formed on a semiconductor substrate directly or via an insulating film.
The thermal resistor may be a thermistor resistor for compensating for temperature characteristics of a circuit formed on the semiconductor substrate.
The method for producing a semiconductor integrated circuit of the present invention includes the steps of: forming a semiconductor integrated circuit including a thermal resistor made of tungsten silicide nitride; measuring electric characteristics of the semiconductor integrated circuit; obtaining a difference between the measured electric characteristics and desired electric characteristics to calculate a required adjusting amount of a resistance of the thermal resistor; and adjusting the resistance of the thermal resistor by the adjusting amount through current-carrying heating of the thermal resistor.
Preferably, the current-carrying heating is conducted by using a current source.
The method for producing a semiconductor integrated circuit, which is provided in accordance with another aspect of the present invention, includes the steps of: forming a tungsten silicide nitride film on a semiconductor substrate; patterning the tungsten silicide nitride film in a predetermined pattern to form a thermal resistor; and forming a pair of electrodes to be connected to the thermal resistor.
The method may further include the step of forming another circuit portion on the semiconductor substrate.
In one embodiment, the tungsten silicide nitride film is formed by reactive sputtering in a reduced-pressure atmosphere containing nitride gas with a target made of tungsten silicide containing silicon.
Thus, the invention described herein makes possible the advantage of providing: (1) a semiconductor integrated circuit in which a temperature-compensating thermistor resistor having a large temperature coefficient is internally provided, and the resistance of the thermistor resistor can be adjusted without giving damage to other semiconductor devices; and (2) a method for producing the same.
This and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.
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Fukuda Takeshi
Fukui Takeshi
Furukawa Hidetoshi
Takenaka Hiroshi
Ueda Daisuke
Fourson George
Garcia Joanie A.
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