Browse Prior Art Database

SLURRY SUPPLY SYSTEM DESIGN FOR CHEMICAL MECHANICAL POLISHING

IP.com Disclosure Number: IPCOM000008583D
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2002-Jun-25
Document File: 2 page(s) / 116K

Publishing Venue

Motorola

Related People

Daniel A. Koos: AUTHOR [+3]

Abstract

Slurries used for Chemical Mechanical Polishing (CMP) are typically a colloidal suspen- sion of an abrasive and a chemical oxidant. In the ideal case the slurry is a homogenous mixture of suspended particles with a well defined particle size distribution. The slurry is supplied to the polisher from a supply drum via a distribution system con- sisting of a day tank, supply lines and associated hardware. The distribution system typically has a separate controller with associated software and communication links to the polisher.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 50% of the total text.

Page 1 of 2

MOTOROLA Technical Developments

SLURRY SUPPLY SYSTEM DESIGN FOR CHEMICAL MECHANICAL POLISHING

by Daniel A. Koos, Randy McClamrock and Paul Bajnoczy

BACKGROUND

  Slurries used for Chemical Mechanical Polishing (CMP) are typically a colloidal suspen- sion of an abrasive and a chemical oxidant. In the ideal case the slurry is a homogenous mixture of suspended particles with a well defined particle size distribution. The slurry is supplied to the polisher from a supply drum via a distribution system con- sisting of a day tank, supply lines and associated hardware. The distribution system typically has a separate controller with associated software and communication links to the polisher.

PROBLEM

  Although the CMP slurry is designed to be homogenous mixture, agglomeration and settling lead to non-homogeneous mixtures in which the par- ticle size often exceeds tolerable limits. Settling and

agglomeration occur in the slurry drum prior to use and may also take place in the slurry distribution system. This problem is exacerbated by drying and coating of the slurry on surfaces within the drum, the distribution tank, and the slurry lines. Typical CMP slurry distribution systems draw the slurry from the supply drum into a day tank. In order to keep the slung well mixed the slurry is drawn from the bottom of the day tank and recirculated in a loop from which the polisher(s) draw the slurry (see Figure I). As a result of the typical supply system design, particulate and agglomerations are reintroduced into the supply of slurry reaching the polishing tool. Introducing these large slurry particulates into the CMP process results in yield loss due to defects generated as scratches and pits on product wafers. In addition, equipment uptime is reduced due to clogging of valves and lines caused by sedimentation and collection of these large particulates in critical areas of the distribution system.

Prior Art :

___________ mLLw ____________,

I

--) To Polisher

supply drum

Fig. 1 Slurry Supply System, Existing Technology

'S' Momrola. 1°C. 19%

96 March 1998

[This page contains 14 pictures or other non-text objects]

Page 2 of 2

MOTOROLA Technicul Developments

SOLUTION

  The problems associated with handling and di...