Ferroelectric memory and method for manufacturing the same
View Patent ↗A capacitor upper electrode and a wiring are electrically connected to each other by using a plug and a conductive layer formed below a capacitive element without using a plug that directly connects the capacitor upper electrode to the wiring provided thereon via an interlayer insulating film therebetween. Alternatively, the capacitor upper electrode is covered by a conductive hydrogen barrier film, and the capacitor upper electrode and the wiring are electrically connected to each other via both a plug connecting the wiring and the conductive hydrogen barrier film to each other and the conductive hydrogen barrier film.
1. A method for manufacturing a ferroelectric memory, comprising the steps of:
forming a transistor in one region on a semiconductor substrate;
forming a conductive layer in another region on the semiconductor substrate;
forming a first interlayer insulating film on the semiconductor substrate including the transistor and the conductive layer;
forming a first plug connected to the transistor and a second plug connected to the conductive layer through the first interlayer insulating film;
forming a capacitor lower electrode on the first interlayer insulating film so as to be connected to the first plug and a connection pad on the first interlayer insulating film so as to be connected to the second plug;
forming a capacitor insulative film made of a ferroelectric film on the capacitor lower electrode so as to extend over and span a space between the capacitor lower electrode and the connection pad;
forming an opening in a portion of the capacitor insulative film that is above the second plug;
forming a capacitor upper electrode on the capacitor insulative film including the opening so as to be electrically connected to the connection pad via the opening; and
forming a wiring so as to be electrically connected to the capacitor upper electrode via the conductive layer and the second plug,
wherein the step of forming the opening is performed before patterning an insulating film to be the capacitor insulative film; and
the step of forming the capacitor upper electrode includes the step of simultaneously patterning the insulative film to be the capacitor insulative film and a conductive film to be capacitor upper electrode.
2. A method for manufacturing a ferroelectric memory, comprising the steps of:
forming a transistor in one region on a semiconductor substrate;
forming a conductive layer in another region on the semiconductor substrate;
forming a first interlayer insulating film on the semiconductor substrate including the transistor and conductive layer;
forming a first plug connected to the transistor and a second plug connected to the conductive layer through the first interlayer including film;
forming a capacitor lower electrode on the first interlayer insulating film so as to be connected to the first plug;
forming a capacitor insulative film made of a ferroelectric film on the capacitor lower electrode so as to extend at least over an area above the second plug;
forming an opening in a portion of the capacitor insulative film that is above the second plug;
forming a capacitor upper electrode on the capacitor insulative film including the opening so as to be electrically connected to the second plug via the opening;
forming a second interlayer insulating film on the first interlayer insulating film including the capacitor upper electrode;
forming a third plug connected to the conductive layer through the first interlayer insulating film and the second interlayer insulating film; and
forming a wiring on the second interlayer insulating film so as to be connected to the third plug,
wherein the step of forming the opening is performed before patterning an insulative film to be the capacitor insulative film, and
the step of forming the capacitor upper electrode includes the step of simultaneously patterning the insulative film to be the capacitor insulative film and a conductive film to be the capacitor upper electrode.
3. The method for manufacturing a ferroelectric memory of claim 1 , wherein the step of forming the capacitor lower electrode includes the step of forming a connection pad on the first interlayer insulating film so as to be connected to the second plug; and
the step of forming the capacitor upper electrode includes the step of forming the capacitor upper electrode so as to be connected to the connection pad.
4. The method for manufacturing a ferroelectric memory of claim 1 , wherein the conductive layer is an impurity diffusion layer formed in a surface portion of the semiconductor substrate, or a suicide layer formed in a surface portion of the impurity diffusion layer.
5. The method for manufacturing a ferroelectric memory of claim 1 , wherein:
the first interlayer insulating film includes a lower layer film and an upper layer film formed on the lower layer film; and
the conductive layer is formed between the lower layer film and the upper layer film.
6. The method for manufacturing a ferroelectric memory of claim 1 , wherein at least a portion the capacitor upper electrode is made of a Pt film or a Pt-containing alloy film.