Motorola Corporation

John G Franka

Jonathan C Dahm

Gary A DePinto

Bich-Yen Nguyen

Philip J Tobin

Israel A Lesk

Paul T Lin

Young Limb

Michael R Cherniawski

Joe Steinberg

Gary L Huffman

Ross A Fisher

Harry S Morgan

A multi-directional flow of isopropyl alcohol vapor is used to uniformly dry a semiconductor substrate. In one embodiment of the invention, isopropyl alcohol vapor (19), which is generated by an external vapor source (30), is injected into the vapor drying system at a location near the top portion (28) of the semiconductor substrate (20), while internally generated isopropyl alcohol vapors (18) are directed toward the bottom portion (26) of the semiconductor substrate (20). Therefore, both the top (28) and the bottom (26) portions of the semiconductor substrate (20) are dried at approximately the same time.

Method for vapor drying

Contaminants are removed from a semiconductor material by heating the semiconductor material to temperature within the range of a minimum temperature where a halogen compound will decompose to halogen atoms without the use of ultraviolet irradiation and react with contaminants present on the semiconductor material and a maximum temperature of 800.degree. C., wherein less than or equal to approximately 50 Angstroms of oxide is formed on the semiconductor material. The ambient in which the semiconductor material is heated is an ambient comprised of a nonreactive gas and a halogen compound for at least a time sufficient to remove a substantial amount of contaminants from the semiconductor material.

Method of removing contaminants

A polysilicon layer may need to have electrical characteristics which are relatively uniform from wafer to wafer. The use of polysilicon as a resistor is one such example. In order to obtain the requisite uniformity, the temperature of the wafers which are receiving the polysilicon must all be the same within a tight tolerance. The reaction takes place in a furnace which takes a long time to reach the requisite temperature tolerance. While the furnace is stabilizing the temperature, oxide, which is an insulator, is growing on the contact locations of the various substrates. To minimize the deleterious oxide formation, a thin layer of polysilicon is deposited at a time significantly prior to the time that the furnace stabilizes which ensures a good, low-resistance contact. The remainder of the polysilicon is then deposited on the thin layer of polysilicon after the temperature has stabilized to obtain the requisite wafer-to-wafer resistance uniformity. The result is consistently low-resistance contacts and wafer-to-wafer uniformity for the resistance of the resistors.

Deposition of a conductive layer for contacts

In a process for depositing nitride on semiconductor wafers in a tube, streaks can develop on the wafers. The streaks are eliminated by using a quartz tube which has an inside surface coated with polysilicon for the nitride deposition.

Process for improving nitride deposition on a semiconductor wafer

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Austin, TX, United States of America

John G Franka