Quartz Unlimited LLC.

5030 Champion Blvd., Suite G6-247

Boca Raton, FL 33496

Phone: 888 264-3879

Fax: 888-263-1647

enail: ferenc@quartzunlimited.com

 

Supplying the semiconductor manufacturing industry with quartz wafers for over 25 years

MATERIAL SELECTION GUIDE

 

 

There are two different type of quartz material to choose from, Fused Quartz and Fused Silica.

 

 

 

FUSED QUARTZ

Naturally occuring crystalline (sand) is crushed into powder and passes through numerous purifying processes. The resulting pure powder is fused by either of two different processes to manufacture clear fused quartz ingots.


Electrically fused:

High energy electrical heating process melts (fuses) the powder, casting very large ingots which will be cut up during fabrication. The result of this process is a fairly pure material with a very low (~15ppm) Hydroxil (OH) content, however it contains some fine bubbles, inclusions and and minute amount of other contaminants. Currently this is the most widely used material in the semiconductor industry, however it is less desitable for quartz wafers except in partical application where the OH content and the electrial properties and dielectric constant is in consideration.

 

Flame fused:

In this manufacturing process the powder is fused with Oxigen-Hydrogen flame. This clear fused quartz material is extremely pure and virtually bubble free. However the OH content is somewhat higher (~180ppm) than the electric fused quartz. This material is appropriate for allmost all wafers but the most demanding optical and semiconductor grade applications.

 

FUSED SILICA

The manufacturing of this form of Silicon Dioxide does not uses naturally occuring material but its derived synthetically, hence the name Synthetic Quartz. There are two different way this material is produced.

 

Flame fused:

In this process particular chemicals are fused with Oxigen-Hydrogen flame. This material processing method involves various drying processes, thus numerous grades are available with OH content ranging from 180ppm to as high as 1200ppm. The OH content effects the maximum processing temperature for the wafer so this parameter should be carefully evaluated.

 

Dry VAD process:

This process to manufacture synthetic quartz is one of the most advanced and sophisticated method available today. This methos produces the highest grade material todate. The exremely low OH content (<2ppm) allows for very high wafer processing temperatures among other notable benefits. The optical characreristics are the highesr grade but also the most expensive.