Chemical-mechanical polishing techniques and methods of end point detection in chemical-mechanical polishing processes

• US 5,439,551 A
• Filed: 03/02/1994
• Issued: 08/08/1995
• Est. Priority Date: 03/02/1994
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Doan, Trung T., Meikle, Scott
• Primary Examiner(s): Fourson, George
• Assistant Examiner(s): BILODEAU, THOMA
• Application Number:
  US08/205,312
• Time in Patent Office: 524 Days
• Field of Search: 437/7, 156/626, 156/636
• US Class Current: 438/5
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 49/003 involving acoustic means

Abstract

A semiconductor processing method of detecting polishing end point in a chemical-mechanical polishing planarization process includes the following steps: a) chemical-mechanical polishing an outer surface of a semiconductor substrate using a chemical-mechanical polishing pad; b) during such chemical-mechanical polishing, measuring sound waves emanating from the chemical-mechanical polishing action of the substrate against the pad; c) detecting a change in the sound waves as the surface being chemical-mechanical polished becomes substantially planar; and d) ceasing chemical-mechanical polishing upon detection of the change. Alternately instead of ceasing chemical-mechanical polishing, a mechanical polishing process operational parameter could be changed upon detection of the change and then continuing mechanical polishing with the changed operational parameter. In another aspect of the invention, first and second layers to be polished are provided on a semiconductor wafer. The second layer is in situ measured during polishing to determine its substantial complete removal from the substrate by chemical-mechanical polishing. Such in situ measuring of the second layer during polishing might be conducted by a number of different manners, such as by acoustically, chemically, optically or others. Also claimed is a polishing apparatus for acoustically monitoring polishing action.

Claims

1. A semiconductor processing method of detecting polishing end point in a chemical-mechanical polishing planarization process comprising the following steps:

chemical-mechanical polishing an outer surface of a semiconductor substrate using a chemical-mechanical polishing pad;

during such chemical-mechanical polishing, measuring sound waves emanating from the chemical-mechanical polishing action of the substrate against the pad;

detecting a change in the sound waves as the surface being chemical-mechanical polished becomes substantially planar; and

ceasing chemical-mechanical polishing upon detection of the change.

2. A semiconductor processing chemical-mechanical polishing method comprising the following steps:

chemical-mechanical polishing an outer surface of a semiconductor substrate using a chemical-mechanical polishing pad;

during such chemical-mechanical polishing, measuring sound waves emanating from the chemical-mechanical polishing action of the substrate against the pad;

detecting a change in the sound waves as the chemical-mechanical polishing action continues; and

changing a chemical-mechanical polishing process operational parameter upon detection of the change and then continuing chemical-mechanical polishing with the changed operational parameter.

3. The semiconductor processing chemical-mechanical polishing method of claim 2 comprising changing multiple chemical-mechanical polishing process operational parameters upon detection of the change and then continuing chemical-mechanical polishing with the changed operational parameters.

4. A semiconductor processing method of chemical-mechanical polishing comprising the following sequential steps:

providing a first layer of varying topography to be chemical-mechanical polished onto a semiconductor substrate, the first layer comprising a first material;

providing a second layer to be chemical-mechanical polished over the first layer, the second layer comprising a second material which chemical-mechanical polishes at a rate slower than the first layer for a range of chemical-mechanical polishing process operational parameters;

chemical-mechanical polishing the second layer to a point where a portion of the first layer is outwardly exposed to chemical-mechanical polishing action, thus defining polishing surface having outwardly exposed portions of each of the first and second layers;

chemical-mechanical polishing exposed portions of each of the first and second layers within the range of parameters; and

detecting a change in sound waves emanating from the wafer during polishing upon substantially complete removal of the second layer material from the substrate.

5. A semiconductor processing method of detecting polishing end point in a mechanical polishing planarization process comprising the following steps:

mechanically polishing an outer surface of a semiconductor substrate using a mechanical polishing pad;

during such mechanical polishing, measuring sound waves emanating from the mechanical polishing action of the substrate against the pad;

detecting a change in the sound waves as the surface being mechanically polished becomes substantially planar; and

ceasing mechanical polishing upon detection of the change.

6. A semiconductor processing mechanical polishing method comprising the following steps:

mechanical polishing an outer surface of a semiconductor substrate using a mechanical polishing pad;

during such mechanical polishing, measuring sound waves emanating from the mechanical polishing action of the substrate against the pad;

detecting a change in the sound waves as the mechanical polishing action continues; and

changing a mechanical polishing process operational parameter upon detection of the change and then continuing mechanical polishing with the changed operational parameter.