Siemens Aktiengesellschaft

International Business Machines Corporation

Infineon Technologies Ag

Robert Ploessl

Chenting Lin

Jeremy K Stephens

Karl E Boggs

Maria Ronay

Florian Schnabel

Bertrand Flietner

Bertrand Flienter

Monika Gschoederer

Joachim F Nuetzel

A two-step chemical mechanical polishing (CMP) process is provided to minimize (reduce) dishing of metal lines in trenches in an insulation (oxide) layer of each of a plurality of semiconductor wafers during fabrication thereof. For each wafer, the first step involves CMP of a metal layer disposed on the oxide layer and having a lower portion located in the trenches for forming metal lines and an upper portion overlying the lower portion. The first step polishing uses a first polishing pad to remove the bulk of the metal layer upper portion while generating concomitant CMP residue, and leaves a minimized (reduced) remainder of the metal layer upper portion without dishing of the metal layer lower portion in the trenches. The second step continues the CMP with a second polishing pad to remove the remainder of the metal layer upper portion with minimized (reduced) dishing of the metal layer lower portion to an extent providing the metal lines as individual metal lines in the trenches. Each wafer undergoes the first step polishing with the first polishing pad and then the second step polishing with the second polishing pad. The second polishing pad has at most a deficient content of prior accumulated concomitant CMP residue, e.g., is a relatively fresh (clean) polishing pad.

Metal chemical polishing process for minimizing dishing during semiconductor wafer fabrication

An improved hard mask is provided to reduced pad erosion during semiconductor fabrication. The hard mask includes an etch stop layer between first and second hard mask layers.

Reduced pad erosion

A method of forming very small diameter metal lines in a dielectric layer 12 comprising forming an opening in the dielectric layer using photolithographic techniques, filling the opening with an insulating material 16 and planarizing the dielectric layer using chemical metal polishing techniques, which are continued so as to form small trenches 17 in the dielectric material on either side of the insulating material, filling in the trenches with metal and planarizing the metal layer using chemical metal polishing.

Formation of sub-groundrule features

The method of polishing metal layers on wafers comprises the steps of: providing indicator areas on said wafer, said indicator areas having combinations of line widths and pattern factors violating existing ground rules of metal lines thereby said indicator areas being dished out during said polishing using a chemical-mechanical polisher to polish the metal layers to remove material therefrom, inspecting indicator areas on the wafer to determine an amount of material removed from said areas, and adjusting the operation of the chemical-mechanical polisher in response to the inspection of the indicator areas. The indicator areas may include macroblocks comprised of a multitude of individual blocks. The wafer may be inspected by optically identifying the polishing state of to blocks in the macroblock. Additionally, the process may be automated for mass production. A feedback loop to the polisher can be formed where data from optical inspection of macroblocks on a polished wafer can be immediately fed back to the polisher in order to adjust process parameters.

CMP process using indicator areas to determine endpoint

Improved technique of forming trench capacitors without causing excessive erosion at the edges of the array region resulting from polishing. The erosion is reduced by providing a block mask to protect the array region while partially removing a portion of the hard mask used to etch the trenches in the field region. The partial etch equalizes the height of the hard mask in the array and field region after formation of the deep trenches by a reactive ion etch.

Reduction of pad erosion

A polishing pad conditioner and a method for conditioning a polishing pad of a chemical/mechanical polishing system. The polishing pad conditioner includes a body defining an upper surface and a lower surface; at least one conditioning element mounted at the lower surface of the body, the conditioning element including a conditioning surface and an opening adjacent the conditioning surface; and a vacuum source operatively connected to the opening in the conditioning element. The method for conditioning a polishing pad includes the steps of holding a polishing pad conditioner including a conditioning element, a conditioning surface thereon and an opening in the conditioning element adjacent the conditioning surface in contact with a surface of the polishing pad; applying a vacuum source to the pad, the vacuum source being operatively connected to the conditioning element; and conditioning the surface of the polishing pad while simultaneously vacuuming particles therefrom.

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Glen Allen, VA, United States of America

Robert Ploessl