Method and apparatus for endpointing mechanical and chemical-mechanical planarization of microelectronic substrates

In a planarizing processes of a microelectronic substrate on a polishing pad, a method of endpointing the planarizing process, comprising:

• pressing the substrate against the polishing pad in the presence of a planarizing fluid on the polishing pad, the planarizing fluid including a liquid solution and a plurality of viscosity altering elements that are separate from a plurality of abrasive particles in one of the planarizing fluid or the polishing pad, the viscosity altering elements being colloidal with the liquid solution;
• changing the viscosity of the planarizing fluid between the substrate and the polishing pad as the substrate becomes at least substantially planar, the viscosity altering elements causing a change in the viscosity of the planarizing fluid that changes a drag force between the substrate and planarizing medium defined by the planarizing fluid and the polishing pad;
• and
• stopping removal of material from the substrate when the drag force between the substrate and the planarizing medium changes.

A method of planarizing a microelectronic substrate, comprising:

• depositing a planarizing fluid onto a polishing pad, the planarizing fluid having a plurality of friction elements that cause a change in drag force between the substrate and the polishing pad as the substrate becomes at least substantially planar, and at least one of the planarizing fluid and the polishing pad having a plurality of abrasive particles;
• moving at least one of the substrate and the polishing pad with respect to the other to impart relative motion between the substrate and the polishing pad, the relative motion removing material from a front surface of the substrate, and the relative motion causing a first rate of change of drag force between the substrate and the polishing pad when the front surface of the substrate is not at least substantially planar;
• and
• stopping removal of material from the front surface of the substrate when the rate of change of the drag force between the substrate and the polishing increases to a second rate greater than the first rate.

A method of planarizing a microelectronic substrate comprising:

• moving at least one of the substrate and a polishing pad with respect to the other to impart relative motion between the substrate and the polishing pad in the presence of a planarizing fluid, the polishing pad and the planarizing fluid removing material from a front surface of the substrate;
• increasing the viscosity of the planarizing fluid between the substrate and the polishing pad, the planarizing fluid having a first viscosity when the front face of the substrate is not substantially planar and a second viscosity greater than the first viscosity as the substrate becomes at least substantially planar;
• and
• stopping removal of material from the front surface of the substrate when the drag force between the substrate and a planarizing medium defined by the planarizing fluid and the polishing pad increases corresponding to a change in viscosity of the planarizing fluid from the first viscosity to the second viscosity.

A planarizing fluid for planarizing a microelectronic substrate, comprising:

• a liquid solution;
• and
• a plurality of friction element elements in the solution, the friction elements being composed of a material that causes a rapid increase in friction between the substrate and a planarizing medium as the substrate becomes substantially planar;
• and
• a plurality of abrasive particles in the liquid solution, the abrasive particles being composed of material that abrades material from a surface of the substrate during planarizing of the substrate.

A planarizing machine for removing material from a microelectronic substrate, comprising:

• a table;
• a polishing pad attached to the table;
• a planarizing fluid deposited onto the polishing pad, at least one of the polishing pad and the planarizing fluid having a plurality of abrasive particles, and the planarizing fluid also having a plurality of resistance elements, the resistance elements causing an increase in the viscosity of the planarizing fluid from a first viscosity when the substrate is not substantially to a second viscosity as the substrate becomes at least substantially planar;
• a carrier assembly including a substrate holder to hold the substrate, the carrier assembly moves the substrate holder to press the substrate against the planarizing fluid and the polishing pad, and at least one of the substrate holder and the table being moveable in a plane to translate the polishing pad with respect to the substrate;
• and
• a friction sensor to measure an increase in friction between the substrate and polishing pad.