US 6,730,573 B1 · MIM and metal resistor formation at CU beol using only one extra mask

Abstract

An improved process for fabricating simultaneously high capacitance, less than 0.13 micron metal-insulator-metal capacitors, metal resistors and metal interconnects, has been developed using single or dual damascene processing. The key advantage is the use of only one additional mask reticle to form both MIM capacitor and resistor, simultaneously. Several current obstacles that exist in BEOL, back end of line, are overcome, namely: (a) the use of two or more photo-masks to make <0.13 um MIM capacitors, (b) undulated copper surfaces, when dielectrics are deposited directly upon it, (c) particles generation concerns during etching, when attempting an etch stop on the bottom MIM plate layers, and finally, (d) dishing during CMP occurs when large copper MIM plates are required, with subsequent capacitance matching problems. The integrated method overcomes the above obstacles and simultaneously forms MIM capacitors, metal resistors and metal interconnects using damascene processing. In addition, the method of forming the MIM capacitors, described herein, can also be used to form anti-fuse devices, in field-programmable gate arrays, FPGA.

Claims31

Dependent claims

A method for fabricating metal-insulator-metal capacitors, MIM, metal resistors, and copper back end of line interconnect wiring, comprising:

providing a first intermetal dielectric layer overlying a semiconductor substrate;
forming bottom MIM trench openings and other metal line openings in the first intermetal dielectric layer patterning using a first mask, photoresist process one;
forming a first metal MIM electrode and other metal interconnect wiring lines filling said openings;
forming shallow trench openings in a thin second intermetal dielectric layer, over existing first metal MIM electrode and interconnects, patterning using the first mask again, photoresist process two;
forming a bottom plate barrier layer in the shallow trench openings and planarizing back the top surface, leaving the bottom plate barrier layer in the trench;
forming a high dielectric constant insulator layer over the thin second intermetal dielectric layer and bottom plate barrier layer;
forming a second metal MIM electrode, interconnects, and metal resistors over the high dielectric constant insulator layer, patterning using a second mask, photoresist process three, thus completing the MIM capacitors, metal resistors and copper wiring.

4 more elements

A method for fabricating metal-insulator-metal capacitors, MIM, metal resistors, and copper back end of line interconnect wiring, and electrical contacts therein, comprising:

providing a first intermetal dielectric layer overlying a semiconductor substrate;
forming bottom MIM trench openings and other metal line openings in the first intermetal dielectric layer patterning using a first mask, photoresist process one;
forming a first metal MIM electrode and other metal interconnect wiring lines filling said openings;
forming shallow trench openings in a thin second intermetal dielectric layer, over existing first metal MIM electrode and interconnects, patterning using the first mask again, photoresist process two;
forming a bottom plate barrier layer in the shallow trench openings and planarizing back the top surface, leaving the bottom plate barrier layer in the trench;
forming a high dielectric constant insulator layer over the thin second intermetal dielectric layer and bottom plate barrier layer;
forming a second metal MIM electrode, interconnects, and metal resistors over the high dielectric constant insulator layer, patterning using a second mask, photoresist process three, forming MIM capacitors, metal resistors and copper interconnect wiring;
depositing a thick third intermetal dielectric layer over the second metal MIM electrode, interconnects, and metal resistors and over the high dielectric constant insulator layer;
planarizing the third intermetal dielectric layer by chemical mechanical polishing;
forming via openings which connect to both first and second metal, patterning using a third mask, photoresist process four;
forming a metal barrier layer lining the via openings and forming copper metal filling the via openings, forming copper contact vias to both first second metal;
depositing a thick fourth intermetal dielectric layer over copper contact vias and over the third intermetal dielectric layer;
forming large trench openings in the fourth intermetal dielectric layer over the copper contact vias, patterning using a fourth mask, photoresist process five;
forming a metal barrier layer lining the large trench openings and forming copper metal filling the via openings, planarizing the surface by chemical mechanical polish, thus forming electrical contacts through the contact vias below, to the metal-insulator-metal capacitors, MIM, metal resistors, and copper back end of line interconnect wiring.

11 more elements

A method for fabricating metal-insulator-metal capacitors, MIM, metal resistors, and copper back end of line interconnect wiring, using only one extra mask comprising:

providing a first intermetal dielectric layer overlying a semiconductor substrate;
forming a first metal MIM electrode and other metal interconnect wiring lines in a damascene process using a first mask, photoresist process one, in the first intermetal dielectric layer;
forming a bottom plate barrier layer over existing first metal MIM electrode and interconnects patterning in a damascene process using the first mask again, photoresist process two, in a provided second intermetal dielectric layer;
forming a high dielectric constant insulator layer over the second intermetal dielectric layer and bottom plate barrier layer;
forming a second metal MIM electrode, interconnects, and metal resistors over the high dielectric constant insulator layer, patterning using a second mask, photoresist process three;
thus, forming MIM capacitors, metal resistors and copper interconnect wiring with only one extra mask.

3 more elements

Dependencies are inferred from the claim text.

MIM and metal resistor formation at CU beol using only one extra mask

Life of this patent

MIM and metal resistor formation at CU beol using only one extra mask

Life of this patent

Abstract

Claims31