Semiconductor device manufacturing method and semiconductor device
View Patent ↗A technique is provided which makes it possible to achieve both of a reduction in contact resistance in a memory device and a reduction in contact resistance in a logic device even when oxidation is performed during formation of dielectric films of capacitors. Conductive barrier layers ( 82 ) are provided in the top ends of contact plugs ( 83 b ) electrically connected to ones of source/drain regions ( 59 ). Lower electrodes ( 70 ) of capacitors ( 73 ) are formed in contact with the conductive barrier layers ( 82 ) of the contact plugs ( 83 b ) and then dielectric films ( 71 ) and upper electrodes ( 72 ) of the capacitors ( 73 ) are sequentially formed. In the logic region, contact plugs ( 25 ) are formed in an upper layer so that they are in contact respectively with contact plugs ( 33 ) electrically connected to source/drain regions ( 9 ).
1. A semiconductor device comprising:
a semiconductor substrate having a memory region where a memory device is formed and a logic region where a logic device is formed;
a first insulating film provided on said semiconductor substrate;
first and second contact plugs provided in said first insulating film with their respective top surfaces exposed from said first insulating film, and electrically connected to said semiconductor substrate in said memory region;
a third contact plug provided in said first insulating film with its top surface exposed from said first insulating film, and electrically connected to said semiconductor substrate in said logic region;
an MIM capacitor having a lower electrode, an upper electrode, and a dielectric film interposed therebetween, said lower electrode being in contact with the top surface of said first contact plug;
a second insulating film provided on said first insulating film and covering said MIM capacitor;
a fourth contact plug provided in said second insulating film and being in contact with said second contact plug; and
a fifth contact plug provided in said second insulating film and being in contact with said third contact plug;
said first contact plug having first conductive film below a top portion;
means for preventing the first conductive film from being oxidized during formation of the dielectric film so as to reduce contact resistance;
said second contact plug having a second conductive barrier layer in its top portion and having, in a remaining portion, a second conductive film having a higher conductivity than said second conductive barrier layer;
means for reducing contact resistance between said fourth contact plug and said semiconductor substrate;
said third contact plug having a third conductive barrier layer in its top portion and having, in a remaining portion, a third conductive film having a higher conductivity than said third conductive barrier layer;
said fifth contact plug extending into said first insulating film and being in contact with said third conductive barrier layer and a side surface of said third conductive film,
wherein a reduction in contact resistance in a logic device is achieved.
2. The semiconductor device according to claim 1 , wherein said fourth and fifth contact plugs are in contact with the entire periphery of said side surface of said second conductive film.
3. The semiconductor device according to claim 1 , further comprising:
first and second source/drain regions formed at a given distance from each other in an upper surface of said semiconductor substrate in said memory region; and
a gate structure provided on the upper surface of said semiconductor substrate between said first and second source/drain regions,
wherein said first insulating film is provided on said semiconductor substrate and covers said gate structure,
said first and second contact plugs are electrically connected respectively with said first and second source/drain regions,
said fourth contact plug has its top surface exposed from said second insulating film and
said semiconductor device further comprises a bit line provided on said second insulating film and being in contact with said fourth contact plug.