Efficient metal-insulator-metal capacitor fabrication
Methods of forming capacitors include forming a self-assembled pattern of periodic first and second domains using first and second block copolymer materials over a substrate. The second block copolymer material is etched away. Material from the substrate is etched based on a pattern defined by the first block copolymer material to form cavities in the substrate. A capacitor stack is conformally deposited over the substrate, such that the capacitor stack is formed on horizontal surfaces of the substrate and vertical surfaces of the cavities.
1. A method for forming a capacitor, comprising:
forming a self-assembled pattern of periodic first and second domains using first and second block copolymer materials over a substrate that includes an embedded bottom contact;
etching away the second block copolymer material;
etching material from the substrate based on a pattern defined by the first block copolymer material to form a cavity in the substrate to a depth below a top surface of the embedded bottom contact; and
conformally depositing a capacitor stack over the substrate, such that the capacitor stack is formed in contact with the embedded bottom contact and vertical surfaces of the cavity.
2. The method of claim 1 , further comprising forming a mask over the capacitor stack to define a capacitor area and etching away the capacitor stack from areas that are not covered by the mask.
3. The method of claim 2 , further comprising forming a mask over the substrate before etching material from the substrate to limit an etched area.
4. The method of claim 3 , wherein forming the mask over the capacitor stack and forming the mask over the substrate comprise lithographically defining the respective masks using a same lithographic pattern and developers of opposite polarity.
5. The method of claim 1 , further comprising depositing a layer of dielectric material over the capacitor stack.
6. The method of claim 5 , forming a top conductive contact through the layer of dielectric material to contact the capacitor stack.
7. The method of claim 1 , wherein the first block copolymer material is polystyrene and the second block copolymer material is poly(methyl methacrylate).
8. A method for forming a capacitor, comprising:
forming a self-assembled pattern of periodic first and second domains using first and second block copolymer materials over a substrate that includes an embedded bottom contact;
etching away the second block copolymer material;
forming a first mask over the substrate;
etching material from the substrate in an area exposed by the first mask and the first block copolymer material to form cavities in the substrate to a depth below a top surface of the embedded bottom contact;
conformally depositing a capacitor stack over the substrate, such that the capacitor stack is formed in contact with the bottom contact and vertical surfaces of the cavities;
forming a second mask over the capacitor stack to define a capacitor area, wherein a same lithographic pattern and a developer of opposite polarity is used to form the second mask as is used to form the first mask; and
etching away the capacitor stack from areas that are not covered by the second mask.
9. The method of claim 8 , further comprising depositing a protective layer over the capacitor stack before forming the second mask.
10. The method of claim 8 , further comprising depositing a layer of dielectric material over the capacitor stack.
11. The method of claim 10 , forming a top conductive contact through the layer of dielectric material to contact the capacitor stack.
12. The method of claim 8 , wherein the first block copolymer material is polystyrene and the second block copolymer material is poly(methyl methacrylate).