Method and System for an Improved Deep Trench Recess-1 Process
Publication Date: 2012-May-07
The IP.com Prior Art Database
A method and system is disclosed for improving recess depth variability by performing a tilted implant of poly stud to create a wet etch selectively.
Page 01 of 4
Method and System for an Improved Deep Trench Recess -1 Process
Disclosed is a method and system for improving recess depth variability by performing a tilted implant of poly stud to create a wet etch selectively. The disclosed method and system may prevent TiN oxidation and water bowing, thus providing a constant recess depth during a deep trench process.
Recess depth variability is usually encountered during a deep trench recess-1 control process. There are a number of factors responsible for recess depth variability, including but not limited to, poly stud height variation. Poly stud height variation is caused due to surface non-uniformity resulting from Chemical Mechanical Planarization (CMP) and/or Deep Trench silicon Reactive Ion Etching (DT Si RIE).
Figure 1 and Figure 2 illustrate the poly stud height variation post CMP and Hard Mask (HM) processing, and a consequent recess depth variability post recess-1 deep trench processing respectively.
Page 02 of 4
The method and system disclosed minimizes the recess depth variability by a tilted implant of poly stud to create a wet etch selectively to poly below surface. For instance, a 30keV 2E15 45-deg tilt and 45-deg rotation quad may be used for implanting the poly stud.
Figure 3 illustrates the process of tilted implant of poly stud, and Figure 4 depicts the poly stud removal with selective wet etching.
Page 03 of 4
Figure 5 illustrates the use of disclosed method and s...