Inhomogenous composite doped film for low temperature reflow

US6319848A · kind A · utility

Assignee

• TEXAS INSTRUMENTS INCORPORATED · US

Inventors

• Andrej Litwin · Stockholm, SE
• Shih-Hsin Ying · Taoyuan, TW

Key dates

• Filing date: Mar 16, 1995
• Grant date: Nov 20, 2001
• Expiry date: Mar 16, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/02129
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Lower reflow temperature in dielectrics is obtained by using a composite dielectric film. The composite dielectric film includes a first layer doped in the conventional range. A borophosphosilicate glass (BPSG) thick layer having concentrations of around 4.4 wt. % boron and around 5.6 wt. % phosphorus is exemplary. The composite dielectric film includes a second layer doped excessively. A BPSG thin layer having concentrations between 1-4 wt. % phosphorus and between 7-8 wt. % boron is exemplary. A capping layer of conventional dopant concentration may be additionally added to prevent outdiffusion. A composite dielectric BPSG film can be reflowed around 700.degree. C. as compared to the typical 800-900.degree. C. range. After reflow, etching away the second highly doped layer removes any potential adverse effects.