Yao-Chi Chang

Title: Yao-Chi Chang: Innovator in Semiconductor Technology

Introduction

Yao-Chi Chang is a prominent inventor based in Tainan, Taiwan. He has made significant contributions to the field of semiconductor technology, particularly in the development of methods for forming and etching shallow trench isolation (STI) structures. With a total of three patents to his name, Chang's work has had a notable impact on the industry.

Latest Patents

Chang's latest patents include a method for forming STI structures with controlled step height. This innovative method involves producing STI structures using a relatively thin nitrogen-containing layer formed over a substrate. The nitrogen-containing layer may consist of silicon nitride (SiN) and silicon oxynitride (SiON) films with a combined thickness of 900 angstroms or less. Trench openings are formed to extend through the nitrogen-containing layer and into the substrate. Chemical vapor deposition is utilized to form a dielectric, such as an oxide, within the trench openings and over the top surface of the nitrogen-containing layer. A polishing operation is then performed to partially polish the CVD dielectric layer, leaving a reduced thickness over the nitrogen-containing layer. Subsequently, a dry etch is used to remove the dielectric from over the nitrogen-containing layer, uniformly receding the top surface of the dielectric within the trench while avoiding dishing effects. The nitrogen-containing layer is ultimately removed to produce STI structures with step heights of less than 500 angstroms.

Another significant patent by Chang is a method for STI etching using endpoint detection. This method involves dry etching a feature to control the etching depth using endpoint detection and a sacrificial hardmask. The process includes providing a substrate for etching a feature opening into the substrate, which is overlaid with at least a first dielectric layer. A second dielectric layer, including a sacrificial hardmask at a predetermined thickness, is then provided over the first dielectric layer. The method employs photolithographic patterning and etching in a first dry etching process to expose the substrate for dry etching the feature opening. In a second dry etching process, the substrate and the sacrificial hardmask layer are etched to endpoint detection of an underlying layer, thereby etching through a predetermined thickness of the substrate.

Career Highlights

Yao-Chi Chang is currently employed at Taiwan Semiconductor Manufacturing Company Limited, a leading player in the semiconductor industry. His work at